Conversations on the Plurality of Worlds

This is an AI modernization of Conversations on the Plurality of Worlds into contemporary English. The original is available from Wikisource. Also available as an epub.

Editor's Introduction

Bernard le Bovier de Fontenelle (1657–1757) was a nephew of the playwright Pierre Corneille and a young man of letters in Paris when he wrote this book. He lived to be nearly a hundred, and for more than forty years he was the permanent secretary of the Paris Academy of Sciences, the man whose job was to explain its work to the public. This book is where he learned how.

It appeared in 1686, when most educated people still pictured the Earth at the center of the universe. A narrator spends a summer at the country house of a Marquise, and over five evenings in her park (a sixth was added the next year) he teaches her the new astronomy: that the Earth turns, that the sun is a star, that the moon is a world like ours, and that the other planets, and perhaps the planets of other stars, are inhabited. She is quick, teasing and hard to fool, and the lessons are also a flirtation. It was the first great book of popular science, one of the first written for a woman reader, and it was read all over Europe for a century.

A few things will seem strange. The science is the science of 1686. Newton's Principia was published the following year, so there is no gravity here. The planets are carried around the sun by "vortices," the great whirlpools of invisible matter that René Descartes had proposed, and Fontenelle treats them as settled. His inhabited planets are a guess he admits is a guess; he enjoys it as much as he argues it. Some of his numbers were already out of date, and the moon has no air. The courtly banter was the manner of the Paris salons, and the jokes about the nations of the world as they turn beneath the Marquise are the joking of his age.

This edition is translated from the French of the 1800 Lyon printing of his final text, from Wikisource. It gives the Preface, his letter to a friend introducing the conversations, and all six evenings. In one sentence of the Fourth Evening, a remark that most Africans have no memory has been left out; the Mercurians he is describing still have none.

Contents

Preface

The First Evening: The Earth Is a Planet That Turns on Itself and Around the Sun

The Second Evening: The Moon Is an Inhabited Earth

The Third Evening: The World of the Moon, and the Other Planets Inhabited Too

The Fourth Evening: The Worlds of Venus, Mercury, Mars, Jupiter and Saturn

The Fifth Evening: The Fixed Stars Are Suns, Each Lighting a World

The Sixth Evening: New Thoughts, and the Latest Discoveries in the Sky

Preface

I'm in much the same position Cicero was in when he set out to put philosophy into his own language, when until then it had been treated only in Greek. He tells us that people said his books would be quite useless. Those who loved philosophy, having gone to the trouble of seeking it out in Greek books, would hardly bother afterward to read it in Latin ones that weren't the originals. And those who had no taste for philosophy didn't care to see it in either Latin or Greek.

To this he answered that just the opposite would happen: people who weren't philosophers would be tempted to become philosophers by how easy the Latin books were to read, and those who already were philosophers from reading the Greek would be glad to see how these subjects had been handled in Latin.

Cicero was right to say so. The excellence of his genius and the great reputation he had already earned guaranteed the success of this new kind of work he was offering the public. But I am far from having the same grounds for confidence in an undertaking so close to his. I wanted to treat philosophy in a way that wasn't philosophical at all. I tried to bring it to a point where it would be neither too dry for people of the world nor too frivolous for scholars. But I'm told, much as Cicero was, that a work like this suits neither the scholars, who can learn nothing from it, nor the people of the world, who won't have any wish to learn anything from it. I'm in no position to give the answer he gave. It may well be that in looking for a middle ground where philosophy would suit everyone, I've found one where it suits no one. Middle grounds are too hard to hold, and I don't think I'll ever feel like putting myself through the same trouble a second time.

I should warn readers of this book who already know something about physics that I never meant to teach them anything. I only meant to entertain them, by presenting in a slightly more pleasant and playful way what they already know on firmer footing. I warn those to whom these subjects are new that I believed I could teach them and entertain them at the same time. The first group will be going against my intention if they look here for anything useful, and the second, if they look only for amusement.

I won't waste time saying that out of all of philosophy I chose the subject best suited to stir curiosity. It seems that nothing should interest us more than knowing how this world we live in is built, whether there are other worlds like it, and whether they are inhabited too. But after all, anyone is free to worry about all this or not. Those who have thoughts to waste can waste them on subjects like these, but not everyone can afford so useless an expense.

In these conversations I've put a woman who is being taught, and who has never heard of any of these things. I thought this fiction would make the work more enjoyable, and would encourage women readers by the example of a woman who, without ever stepping outside the limits of a person with no tincture of science, still understands what she is told and arranges the Vortices and the Worlds in her head without confusion. Why should any woman yield to this imaginary Marquise, who grasps only what she can't help grasping?

To be fair, she does apply herself a little. But what does applying oneself mean here? It doesn't mean digging by sheer meditation into something obscure in itself, or obscurely explained. It only means not reading without picturing clearly what you read. For this whole system of philosophy I ask of women readers only the same attention that The Princess of Cleves demands, if you want to follow its plot properly and appreciate all its beauty. It's true that the ideas in this book are less familiar to most women than those in The Princess of Cleves, but they are no more obscure, and I'm sure that by a second reading at the very most, nothing in it will have escaped them.

Since I didn't mean to build a system in the air, with nothing underneath it, I've used real reasoning from physics, and as much of it as was needed. But fortunately, in this subject, the ideas of physics are cheerful in themselves. At the same moment that they satisfy reason, they give the imagination a spectacle that pleases it as much as if it had been made especially for it.

Where I found a few pieces that weren't quite of that kind, I gave them borrowed ornaments. Virgil did the same in his Georgics, where he rescues the substance of his subject, which is thoroughly dry, with frequent and often very pleasant digressions. Even Ovid did as much in The Art of Love, though the substance of his subject was infinitely more pleasant than anything he could mix into it. Apparently he thought it tiresome to talk about one thing all the time, even if that thing was lessons in gallantry. I needed the help of digressions more than he did, yet I've used them with a fair amount of restraint. I've justified them by the natural freedom of conversation. I've put them only in places where I thought readers would be glad to find them. I've put most of them near the beginning of the work, because that's when the mind isn't yet used to the main ideas I'm offering it. And finally, I've drawn them from my subject itself, or from something quite close to it.

I didn't want to imagine anything about the inhabitants of the worlds that was completely impossible or fantastic. I've tried to say everything that can reasonably be thought about them, and even the fancies I've added to that have some real foundation. The true and the false are mixed together here, but they are always easy to tell apart. I won't try to justify a mixture so odd. That is the most important point of this work, and it's exactly the one I can't give a reason for.

All that's left for me to do in this preface is to speak to one kind of person. They may be the hardest to satisfy, not because there aren't very good reasons to give them, but because they have the privilege of not being paid in all the good reasons, if they don't want to be. These are the scrupulous people, who may imagine there's some danger to religion in putting inhabitants anywhere but on Earth. I respect even the excessive delicacies people have created in matters of religion, and I would have respected this one so far as not to offend it in this work, if it were contrary to my view. But here's what may surprise you: it doesn't apply only to this system, in which I fill an infinity of Worlds with inhabitants. It takes only a small error of imagination to untangle. When someone tells you the Moon is inhabited, you immediately picture men built like us, and then, if you're a bit of a theologian, you're full of difficulties. The descendants of Adam couldn't have spread as far as the Moon, or sent colonies to that country. So the men on the Moon are not sons of Adam. But in theology it would be awkward for there to be men who weren't descended from him. There's no need to say more. Every imaginable difficulty comes down to this, and the words one would have to use in a longer explanation are too worthy of respect to be put in a book as unserious as this one. So the objection rests entirely on the men of the Moon. But it is the objectors who like to put men on the Moon. I don't put any there. I put inhabitants there who are not men at all. What are they, then? I haven't seen them, and it's not from having seen them that I speak of them. And don't suspect that saying there are no men on the Moon is a dodge I'm using to slip past your objection. You'll see that it's impossible for there to be any, given my idea of the infinite diversity that nature must have put into its works. That idea runs through the whole book, and no philosopher can dispute it. So I think I'll hear this objection only from people who talk about these conversations without having read them. But is that any reason to feel reassured? No. On the contrary, I have every reason to fear that the objection will be made to me from a good many quarters.

To Monsieur L***

You want me, Monsieur, to give you an exact account of how I spent my time in the country, at the home of Madame la Marquise de G***. Do you realize that this exact account will be a book, and what's worse, a book of philosophy? You're expecting parties, card games, and hunting, and you'll get planets, worlds, and vortices. Those were almost the only things anyone talked about. Luckily you're a philosopher, and you won't laugh at them as much as someone else would. You may even be glad that I've drawn Madame la Marquise over to the side of philosophy. We couldn't have made a more important conquest, because I count beauty and youth as things of great value, always. Don't you think that if Wisdom herself wanted to present herself to men with success, she'd do well to appear in a form that came a little close to the Marquise's? Especially if she could have the same charm in conversation, I'm convinced everyone would run after wisdom. Still, don't expect to hear marvels when I give you an account of the conversations I had with this lady. You'd almost need as much wit as she has to repeat what she says the way she said it. You'll see in her only that quickness of mind you already know. As for me, I consider her learned, because of the extreme ease with which she could become so. What does she lack? Having opened her eyes on books. That's nothing, and plenty of people have done it their whole lives, and I'd deny them the name of scholar, if I dared. For the rest, Monsieur, you'll owe me something. I know that before going into the details of the conversations I had with the Marquise, I'd be entitled to describe for you the château where she'd gone to spend the autumn. People have often described châteaux on lesser occasions, but I'll spare you that. It's enough for you to know that when I arrived at her house, I found no company there, and I was very glad of it. The first two days were nothing remarkable. They went to exhausting the news of Paris, where I'd come from. But then came the conversations I want to share with you. I'll divide them up by evening, because in fact we only had these conversations in the evenings.

The First Evening: The Earth Is a Planet That Turns on Itself and Around the Sun

So one evening after supper we went out for a walk in the park. The air was deliciously cool, a reward for the very hot day we had just sweated through. The moon had risen maybe an hour before, and its rays, reaching us only through the branches of the trees, made a lovely mix of brilliant white with all that green that looked black. Not a single cloud hid or dimmed even the faintest star. They were all pure, shining gold, made even richer by the blue background they are pinned to. The sight put me in a dreamy mood, and without the Marquise I might have stayed dreaming quite a while. But the presence of so charming a lady wouldn't let me give myself up to the moon and the stars.

"Don't you think," I said to her, "that even the day isn't as beautiful as a beautiful night?"

"Yes," she answered. "The beauty of the day is like a blonde's beauty, which is more dazzling. But the beauty of the night is a brunette's, which is more moving."

"You're very generous," I said, "to give the brunettes that advantage, when you're not one yourself. It's true, though, that the day is the loveliest thing in nature, and the heroines of romances, who are the loveliest things in the imagination, are almost always blonde."

"Beauty is nothing," she replied, "if it doesn't move you. Admit it: the day would never have thrown you into a daydream as sweet as the one I saw you about to fall into just now, looking at this beautiful night."

"I admit it," I said. "But in return, a blonde like you would make me dream better still than the finest night in the world, with all its brunette beauty."

"Even if that were true," she said, "I wouldn't be satisfied with it. Since blondes are supposed to be on the day's side, I'd want the day to have the same effect. Why is it that lovers, who are good judges of what moves us, never address anyone but the night in every song and every elegy I know?"

"The night has to get their thanks," I said.

"Yes," she went on, "but it also gets all their complaints. The day never earns their confidences. Why is that?"

"Apparently," I answered, "because the day doesn't inspire that touch of sadness and passion. At night everything seems to be at rest. You imagine that the stars move more quietly than the sun. The things the sky shows you are gentler, and your eyes settle on them more easily. In short, you dream better, because you flatter yourself that you're the only person in all of nature who's busy dreaming. Maybe, too, the show of the day is too uniform, just one sun and a blue vault. But the sight of all those stars, scattered in confusion and arranged at random into a thousand different shapes, may encourage daydreaming, and a certain disorder of thoughts that we never fall into without pleasure."

"I've always felt what you're describing," she said. "I love the stars, and I'd happily complain about the sun for rubbing them out for us."

"Ah!" I cried. "I can't forgive it for making me lose sight of all those worlds."

"What do you mean, all those worlds?" she asked, looking at me and turning toward me.

"I beg your pardon," I said. "You've set me off on my folly, and my imagination bolted right away."

"What is this folly, then?" she said.

"Alas," I replied, "I'm sorry I have to confess it to you. I've gotten it into my head that every star might well be a world. I wouldn't swear it's true, but I hold it to be true because it gives me pleasure to believe it. It's an idea that delights me, and it has settled into my mind in a cheerful way. To my mind, even truths need charm."

"Well," she said, "since your folly is so agreeable, give it to me. I'll believe anything you like about the stars, as long as I find pleasure in it."

"Ah, Madame," I answered quickly, "it's not a pleasure like the one you'd have at a comedy by Molière. It's a pleasure that lives somewhere in reason, and it only makes the mind laugh."

"What?" she said. "Do you think a person can't enjoy pleasures that live only in reason? I'm going to show you the opposite this very minute. Teach me about your stars."

"No," I said. "It will never be held against me that in a wood, at ten o'clock at night, I talked philosophy to the most charming person I know. Look elsewhere for your philosophers."

I held out in this vein for a while longer, but it was no use, and I had to give in. I did at least make her promise, for the sake of my honor, to keep it a secret. Once I was past any chance of backing out and tried to speak, I found I didn't know where to begin. With someone like her, who knew nothing about physics, I had to start from a long way back, to prove that the Earth could be a planet, the planets so many earths, and all the stars so many suns lighting up worlds. I kept coming back to saying that we'd do better to chat about trifles, as any sensible people would have done in our place. In the end, though, to give her a general idea of philosophy, here is where I began.

"All philosophy," I told her, "rests on just two things: curious minds and bad eyesight. If your eyes were better than they are, you would see for yourself whether the stars are suns lighting up as many worlds, or not. And if, on the other hand, you were less curious, you wouldn't care to know, which would come to the same thing. But we want to know more than we can see, and that's the difficulty. Even so, if we saw well what we do see, that would at least be that much known. But we see it quite differently from how it is. So true philosophers spend their lives not believing what they see, and trying to guess what they don't see, and that isn't a lot to envy, it seems to me.

"On this subject I always picture nature as a great show, like the opera. From where you sit at the opera, you don't see the stage quite as it really is. The sets and the machines have been arranged to look good from a distance, and the wheels and counterweights that make everything move are hidden from your view. So you hardly bother to guess how it all works. There's probably not a hidden stagehand in the pit, though, who wouldn't worry over a flight that struck him as extraordinary and who wouldn't insist on working out how it was done. You can see that this stagehand is a lot like the philosophers.

"But what makes it harder for the philosophers is that in the machines nature puts before our eyes, the ropes are perfectly well hidden. They're hidden so well that people spent a long time guessing what caused the motions of the universe. Picture all the sages at the opera, those Pythagorases, Platos and Aristotles, all those men whose names make such a noise in our ears today. Suppose they were watching Phaethon's flight, where the winds carry him up, that they couldn't see the ropes, and that they had no idea how the backstage was set up. One of them would say, 'A certain secret power lifts Phaethon.' Another, 'Phaethon is made of certain numbers, and they make him rise.' Another, 'Phaethon has a certain fondness for the top of the theater, and he's not comfortable when he's not there.' Another, 'Phaethon isn't made for flying, but he'd rather fly than leave the top of the theater empty.' And a hundred other fancies that amaze me didn't ruin the reputation of all antiquity.

"At last Descartes and some other moderns came along and said, 'Phaethon rises because he's pulled by ropes, and a weight heavier than he is comes down.' So now we no longer believe that a body moves unless it's pulled, or rather pushed, by another body. We no longer believe that it rises or falls, except through a counterweight or a spring. And whoever saw nature as it really is would see only the backstage of an opera house."

"By that account," said the Marquise, "philosophy has become very mechanical."

"So mechanical," I answered, "that I fear people will soon be ashamed of it. They want the universe to be on a large scale only what a watch is on a small one, with everything run by regular movements that depend on how the parts are arranged. Tell the truth. Haven't you sometimes had a grander idea of the universe, and paid it more honor than it deserved? I've known people who thought less of it once they understood it."

"And I," she replied, "think far more of it since I learned that it's like a watch. It's amazing that the order of nature, admirable as it is, turns on such simple things."

"I don't know who gave you such sound ideas," I answered, "but truly, it isn't very common to have them. Plenty of people always carry around in their heads a false sense of wonder wrapped in a darkness they respect. They admire nature only because they think it's a kind of magic where you can't understand anything, and it's certain that in their eyes a thing is dishonored the moment it can be understood. But, Madame," I went on, "you're so well disposed to take in everything I want to tell you that I think all I have to do is draw back the curtain and show you the world.

"From the earth where we stand, the farthest thing we can see is this blue sky, this great vault where the stars seem to be attached like nails. We call them fixed because they seem to have no motion except that of their sky, which carries them along with it from east to west. Between the Earth and this last vault of the heavens, at different heights, hang the Sun, the Moon, and the five other bodies we call the planets: Mercury, Venus, Mars, Jupiter and Saturn. These planets aren't attached to one sky. They move at unequal speeds, so they look at each other from changing angles and form changing patterns together. The fixed stars, by contrast, always keep the same positions relative to one another. The Wagon, for example, that you can see there, made up of those seven stars, has always had the shape it has now and will keep it for a long time. But the Moon is sometimes near the Sun and sometimes far from it, and the other planets do the same.

"That's how things looked to those ancient shepherds of Chaldea, whose great leisure produced the first observations, the foundation of astronomy. Astronomy was born in Chaldea, just as geometry, they say, was born in Egypt, where the flooding of the Nile wiped out the boundaries of the fields, so that everyone wanted to invent exact ways of measuring to tell his field from his neighbor's. So astronomy is the daughter of idleness, and geometry the daughter of self-interest. And if we were talking about poetry, we'd apparently find it the daughter of love."

"I'm glad," said the Marquise, "to have learned this family tree of the sciences, and I can see that I'd better stick to astronomy. Geometry, from what you tell me, would need a more self-interested soul than mine, and poetry would need a more tender one. But I have as much leisure as astronomy could ask for. And luckily we're in the country too, where we lead an almost pastoral life. All of that suits astronomy."

"Don't be fooled, Madame," I said. "Talking about planets and fixed stars isn't the true pastoral life. See if that's how the people in L'Astrée spend their time."

"Oh," she answered, "that kind of shepherding is too dangerous. I prefer the kind those Chaldeans practiced, the ones you were telling me about. Start over, please, and speak a little Chaldean to me. Once they'd recognized this arrangement of the heavens that you described, what came next?"

"What came next," I said, "was guessing how all the parts of the universe must be arranged. That's what the learned call making a system. But before I explain the first of the systems, you need to notice, please, that we're all made by nature like a certain Athenian madman you've heard of, who took it into his head that all the ships entering the harbor of Piraeus belonged to him. Our folly is likewise to believe that all of nature, without exception, is meant for our use. And when you ask our philosophers what use this prodigious number of fixed stars serves, when a part of them would be enough to do what they all do, they tell you coolly that the stars are there to delight their eyes.

"On this principle, people naturally began by imagining that the earth must be at rest in the center of the universe, while all the heavenly bodies, which were made for it, took the trouble to circle around it to give it light. So the Moon was placed above the Earth, and above the Moon they placed Mercury, then Venus, the Sun, Mars, Jupiter, Saturn. Above all that was the sky of the fixed stars. The Earth sat exactly in the middle of the circles these planets trace, and the circles were larger the farther they were from the Earth. As a result, the farther planets took more time to complete their course, which is in fact true."

"But I don't see," the Marquise interrupted, "why you seem not to approve of this arrangement of the universe. It looks quite neat and understandable to me, and for my part I tell you I'm content with it."

"I can boast," I replied, "that I'm making this whole system much gentler for you. If I gave it to you as Ptolemy conceived it, he who invented it, or as those who worked on it after him did, it would throw you into a horrible fright. The motions of the planets aren't so regular that they don't go faster at times and slower at others, one way at one moment and another way at the next, and sometimes farther from the Earth and sometimes closer. So the ancients imagined I don't know how many different circles, interlocked with one another, by which they saved all these oddities. The tangle of all these circles was so great that, at a time when no one yet knew anything better, a king of Castile, a great mathematician but apparently not very devout, said that if God had called him to His council when He made the world, he would have given Him some good advice. The thought is too irreverent. But it's rather amusing that this system should have been an occasion of sin, just because it was so confused.

"The good advice this king wanted to give no doubt concerned getting rid of all those circles that had cluttered up the heavenly motions. Apparently it also concerned getting rid of two or three superfluous skies that had been put beyond the fixed stars. To explain one kind of motion in the heavenly bodies, those philosophers built, beyond the last sky we can see, a crystal sky, which passed that motion on to the skies below. Did they hear of another motion? Right away, another crystal sky. In short, crystal skies cost them nothing."

"And why were they made only of crystal?" asked the Marquise. "Wouldn't some other material have done?"

"No," I said, "the light had to pass through them, and besides, they had to be solid. They absolutely had to be, because Aristotle had found that solidity was bound up with the nobility of their nature, and since he had said it, no one dared doubt it. But then we saw comets that were higher up than people used to think, and they would smash all the crystal of the skies they pass through and shatter the whole universe. So people had to resolve to make the skies of a fluid matter, like air.

"Finally, beyond any doubt, the observations of recent centuries show that Venus and Mercury turn around the Sun and not around the Earth, and on that point the old system is absolutely untenable. So I'm going to propose one to you that accounts for everything, and that would spare the king of Castile from giving any advice. It has a charming simplicity, which alone would make it the one to prefer."

"It sounds," the Marquise interrupted, "as if your philosophy is a kind of auction, where the ones who offer to do the job for less win out over the others."

"That's true," I said, "and it's only that way that we can catch the plan by which nature built her work. She is extraordinarily thrifty. Whatever she can do in a way that costs her a little less, even if that less is almost nothing, you can be sure she'll do it only that way. Yet this thrift is joined with a surprising magnificence that shines in everything she has made. That's because the magnificence lies in the design, and the thrift in the execution. There is nothing finer than a grand design carried out at little expense. We, though, are prone to turn all this upside down in our ideas. We put the thrift in nature's design and the magnificence in the execution. We give her a small design, which she carries out at ten times the expense she needed. That's completely ridiculous."

"I'll be glad," she said, "if the system you're about to tell me about follows nature closely. All that housekeeping will be to the profit of my imagination, which won't have as much trouble understanding what you tell me."

"There's no more useless clutter here," I said. "Picture a German named Copernicus, who makes a clean sweep of all those different circles and all those solid skies that antiquity had imagined. He destroys some, smashes others to pieces. Seized by a noble astronomer's fury, he takes the Earth and sends it far away from the center of the universe, where it had put itself, and in that center he puts the Sun, to whom the honor was much better due. The planets no longer turn around the Earth, and no longer enclose it in the middle of the circles they trace. If they give us light, it's somewhat by chance, because they happen to meet us along their way. Everything now turns around the Sun. The Earth itself turns around it, and to punish it for the long rest it had claimed for itself, Copernicus loads onto it as much as he can of all the motions it used to give the planets and the skies. Finally, of all that heavenly retinue that this little Earth had gathered around itself, nothing is left to it but the Moon, which still turns around it."

"Wait a moment," said the Marquise. "You were seized by such enthusiasm that you explained things so grandly I don't think I understood them. The Sun is at the center of the universe, and there it stays motionless. After it, what comes next?"

"Mercury," I answered. "It turns around the Sun, so that the Sun is more or less the center of the circle Mercury traces. Beyond Mercury is Venus, which likewise turns around the Sun. Then comes the Earth, which, being farther out than Mercury and Venus, traces a bigger circle around the Sun than those planets. Finally come Mars, Jupiter and Saturn, in the order I name them. And you can see that Saturn must trace the biggest circle of all around the Sun, and so it takes more time than any other planet to complete its revolution."

"And the Moon, you're forgetting it," she interrupted.

"I'll find it again," I said. "The Moon turns around the Earth and never leaves it. But since the Earth keeps moving along the circle it traces around the Sun, the Moon follows, always turning around it. And if it goes around the Sun, it's only so as not to leave the Earth."

"I understand you," she answered, "and I love the Moon for staying with us when all the other planets are abandoning us. Admit it: if your German could have made us lose the Moon too, he would gladly have done it. I can see from his whole way of going about it that he was very ill-disposed toward the Earth."

"I'm grateful to him," I replied, "for taking human vanity down a peg. Men had put themselves in the best seat in the universe, and I enjoy seeing the Earth now in the crowd of planets."

"Oh, come!" she said. "Do you think human vanity extends as far as astronomy? Do you think you've humbled me by teaching me that the Earth goes around the Sun? I swear I don't think any less of myself."

"Heavens, Madame," I said, "I know people are less jealous of the rank they hold in the universe than of the one they think they deserve in a drawing room, and the precedence of two planets will never be as big a matter as that of two ambassadors. Still, the same inclination that makes a person want the most honorable place at a ceremony makes a philosopher put himself at the center of the world in a system, if he can. He's delighted that everything is made for him. Perhaps, without noticing, he assumes this flattering principle, and his heart takes an interest in what is a matter of pure speculation."

"Frankly," she replied, "that's a slander you've invented against the human race. By that logic Copernicus's system should never have been accepted, since it's so humbling."

"And in fact," I said, "Copernicus himself was very doubtful about how his opinion would fare. For a very long time he refused to publish it. Finally he made up his mind, at the request of very distinguished people. But on the very day they brought him the first printed copy of his book, do you know what he did? He died. He didn't want to endure all the objections he foresaw, and he neatly got himself out of the business."

"Listen," said the Marquise, "we should do justice to everyone. It's certain that it's hard to imagine that we're going around the Sun. After all, we don't change place, and every morning we find ourselves where we lay down the night before. I can see from your look, I think, that you're going to tell me that, since the whole Earth is moving..."

"Exactly," I interrupted. "It's the same as if you fell asleep in a boat going down the river. When you woke up, you'd find yourself in the same spot, in the same position relative to every part of the boat."

"Yes, but," she answered, "here's a difference. When I woke up I'd find the shore changed, and that would show me quite clearly that my boat had moved. But it's not the same with the Earth. I find everything just as I left it."

"No, Madame, no," I answered. "The shore has changed too. You know that beyond all the circles of the planets are the fixed stars. That's our shore. I'm on the earth, and the earth traces a great circle around the sun. I look toward the center of that circle, and I see the sun. If it didn't wipe out the stars, then looking in a straight line beyond the sun I would necessarily see it lined up with some fixed stars. But I can easily see at night which stars it was lined up with during the day, and it's exactly the same thing. If the earth didn't change its place on the circle where it is, I'd always see the sun lined up with the same fixed stars. But as soon as the earth changes place, I have to see it lined up with other stars. That's the shore that changes every day. And since the earth makes its circle around the sun in a year, over the course of a year I see the sun lined up in succession with different fixed stars that make up a circle. That circle is called the zodiac. Would you like me to draw a figure here in the sand?"

"No," she answered, "I can do without it. Besides, it would give my park a scholarly air, which I don't want it to have. Haven't I heard that a philosopher who was shipwrecked on an island he didn't know cried out to his companions, seeing certain figures, lines and circles drawn on the seashore, 'Courage, friends, the island is inhabited! Here are the footprints of men!' You can see that it's not for me to make footprints like those, and that none should be seen here."

"It's better, indeed," I answered, "that only lovers' footprints be seen here, that is, your name and your monogram, carved on the bark of the trees by the hands of your admirers."

"Let's leave the admirers out of it, please," she said, "and talk about the sun. I understand well enough how we come to imagine that it traces the circle that we trace ourselves. But that circuit takes a year to finish, and the one the sun makes every day over our heads, how does that happen?"

"Have you noticed," I answered, "that a ball rolling along this path would have two motions? It would go toward the end of the path, and at the same time it would spin around itself several times, so that the part of the ball on top would go down and the part on the bottom would come up. The earth does the same thing. In the time it advances along the circle it traces in a year around the sun, it turns on itself in twenty-four hours. So in twenty-four hours every part of the earth loses the sun and finds it again. As we turn toward the side where the sun is, it seems to rise, and when we begin to move away from it, as the turning continues, it seems to sink."

"That's rather funny," she said. "The earth takes everything on itself, and the sun does nothing. And when the moon and the other planets and the fixed stars seem to make a circuit over our heads in twenty-four hours, that's also imagination?"

"Pure imagination," I said, "with the same cause. The planets simply make their circles around the sun in unequal times, according to their unequal distances. The one we see today lined up with a certain point of the zodiac, that circle of fixed stars, we see tomorrow at the same hour lined up with another point, both because it has moved along its circle and because we have moved along ours. We're moving, and the other planets are moving too, but faster or slower than we are. That puts us at different points of view with respect to them and makes their courses look strange to us, in ways I needn't go into. It's enough for you to know that whatever is irregular in the planets comes only from the different way our own motion brings us across them, and that at bottom they are all perfectly regular."

"I'm willing to grant that they are," said the Marquise, "but I wish their regularity cost the Earth less. It hasn't been treated gently, and for so heavy a mass, they're asking a lot of agility."

"But," I answered, "would you rather have the Sun and all the other stars, which are very large bodies, make an immense circuit around the Earth in twenty-four hours, and have the fixed stars, which would be on the biggest circle, cover in one day more than twenty-seven thousand six hundred and sixty times two hundred million leagues? All that has to happen if the Earth doesn't turn on itself in twenty-four hours. Truly, it's far more reasonable for it to make this turn, which is at most nine thousand leagues. You can see that nine thousand leagues, compared with the horrible number I just gave you, is a trifle."

"Oh!" replied the Marquise. "The Sun and the stars are all fire, and motion costs them nothing. But the Earth doesn't look very portable."

"And if you didn't know from experience," I said, "would you believe it was very portable, a big ship armed with a hundred and fifty cannons, carrying more than three thousand men and a huge amount of cargo? Yet it takes only a little breath of wind to make it go across the water, because water is liquid, and since it lets itself be divided easily, it offers little resistance to the ship's motion. Or if the ship is in the middle of a river, it will follow the current without trouble, because nothing holds it back. In the same way the Earth, massive as it is, is easily carried along in the middle of the heavenly matter, which is infinitely more fluid than water and fills all the great space where the planets swim. And where would the Earth have to be clamped down to resist the motion of that heavenly matter and not let itself be swept along? It would be like a little wooden ball managing not to follow the current of a river."

"But," she said again, "how does the earth, with all its weight, hold itself up on your heavenly matter, which must be very light, since it's so fluid?"

"It doesn't follow," I answered, "that what is fluid is lighter. What do you say about our big ship, which with all its weight is lighter than water, since it floats on it?"

"I won't say another word to you," she said, as if angry, "as long as you keep that big ship. But can you really assure me that there's nothing to fear on a top as light as you make the Earth?"

"Well then," I answered, "let's have the earth carried by four elephants, the way the Indians do."

"Now here's a different system!" she cried. "At least I like those people for providing for their safety and laying good foundations, while we Copernicans are reckless enough to be willing to swim at random in this heavenly matter. I bet that if the Indians knew the Earth was in the slightest danger of moving, they'd double the elephants."

"It would certainly deserve it," I said, laughing at her idea. "You shouldn't spare the elephants if you want to sleep soundly. If you need them for tonight, we'll put as many in our system as you like, and then we'll take them away one by one as you feel more reassured."

"Seriously," she said, "I don't think I need them very much already, and I feel brave enough to dare to turn."

"You'll go even further," I said. "You'll turn with pleasure, and you'll form cheerful ideas about this system. Sometimes, for example, I picture myself hanging in the air and staying there without moving while the Earth turns beneath me in twenty-four hours. I watch all those different faces pass under my eyes, some white, some black, some tan, some olive. First it's hats, and then turbans, and then heads of long hair, and then shaved heads. Now cities with church steeples, now cities with long spires topped with crescents, now cities with porcelain towers, now great countries with nothing but huts. Here vast seas, there dreadful deserts. In short, all the infinite variety that is on the surface of the Earth."

"Truly," she said, "all that would be well worth giving twenty-four hours of your time to see. So in the very place where we are right now, I don't mean in this park, but in this very place, taken up in the air, other peoples are constantly passing by and taking our place, and at the end of twenty-four hours we come back to it."

"Copernicus," I answered, "wouldn't understand it any better. First there will pass by here some Englishmen, who will perhaps be reasoning about some political scheme with less cheerfulness than we bring to our philosophy. Then will come a great sea, and there may be some ship in that spot that won't be as comfortable as we are. After that will appear some Iroquois, eating some prisoner of war alive, who will pretend not to care. Then women of the land of Yezo, who will spend all their time preparing their husbands' meals and painting their lips and eyebrows blue to please the ugliest men in the world. Then Tartars who will go very devoutly on pilgrimage to that High Priest who never leaves a dark place where he's lit only by lamps, by whose light he is worshipped. Beautiful Circassian women will make no fuss about granting everything to the first comer, except what they believe belongs essentially to their husbands. Then little Tartars going off to steal women for the Turks and the Persians. And finally us, who will perhaps be spouting still more nonsense."

"It's rather amusing," said the Marquise, "to imagine what you've just described. But if I were looking at all that from above, I'd want the freedom to speed up or stop the Earth's motion, depending on how much the sights pleased me. And I assure you I'd make those who bother with politics, or who eat their enemies, go by very fast. But there are others I'd be curious about. I'd be curious about those beautiful Circassians, for example, with such a peculiar custom. But a serious difficulty occurs to me. If the Earth turns, we change air every moment, and we're always breathing the air of some other country."

"Not at all, Madame," I answered. "The air surrounding the Earth extends only to a certain height, perhaps twenty leagues at most. It follows us and turns with us. You've sometimes seen the work of a silkworm, those cocoons that these little animals spin with such art to imprison themselves. They're made of very tight silk, but they're covered with a certain very light, very loose down. In the same way the Earth, which is fairly solid, is covered from its surface up to a certain height with a kind of down, which is the air, and the whole silkworm cocoon turns at once. Beyond the air is the heavenly matter, incomparably purer, subtler, and even more agitated than the air."

"You present the Earth to me under some very contemptible images," said the Marquise. "Yet it's on this silkworm cocoon that such great labors are carried out, such great wars are fought, and such agitation reigns on every side."

"Yes," I answered, "and all the while nature, which takes no notice of all these little individual motions, carries us all along together in one general motion and plays with the little ball."

"It seems to me," she said, "that it's ridiculous to be on something that turns and to worry so much. But the trouble is that we aren't sure that we're turning. To tell you the truth, all the precautions you take to keep us from noticing the Earth's motion make me suspicious. Is it possible that it won't leave some little perceptible sign by which we could recognize it?"

"The most natural motions," I answered, "and the most ordinary are the ones we feel the least. That's true even in morals. The motion of self-love is so natural to us that most of the time we don't feel it, and we think we're acting from other principles."

"Ah! You're moralizing," she said, "when the subject is physics. That's what I call yawning. Let's go in. Besides, that's enough for the first time. Tomorrow we'll come back here, you with your systems and I with my ignorance."

On the way back to the château, to exhaust the subject of systems, I told her that there was a third, invented by Tycho Brahe, who, determined that the Earth be motionless, placed it at the center of the world and made the sun turn around it, while all the other planets turned around the sun, because after the new discoveries there was no way to make the planets turn around the Earth. But the Marquise, who has a quick and sharp mind, judged that it was too obvious an affectation to exempt the Earth from turning around the Sun when so many other great bodies couldn't be exempted. She judged that the sun was no longer so suited to turning around the Earth, now that all the planets turned around it, and that this system could at most serve to defend the Earth's immobility when one badly wanted to defend it, and not at all to persuade anyone of it. And so it was settled that we would stick with Copernicus's system, which is more uniform and more cheerful, with no mixture of prejudice. Indeed, the simplicity for which it is persuasive, and its boldness, are a pleasure.

The Second Evening: The Moon Is an Inhabited Earth

The next morning, as soon as anyone could go into the Marquise's apartment, I sent to ask how she was and whether she'd been able to sleep while spinning. She sent back word that she was already quite used to the earth's ways, and that she'd spent the night as peacefully as Copernicus himself could have done. A little later some company arrived and stayed until evening, following the tedious custom of the country. We were even grateful to them, because in the country they had every right to stretch their visit into the next day, if they'd wanted to, and they had the decency not to. So the Marquise and I found ourselves free again that evening. We went out to the park once more, and the conversation naturally turned straight back to our systems. She had understood them so well that she thought it beneath her to go over them a second time, and she wanted me to alarm her with something new.

"Very well, then," I said. "The sun, which is now standing still, has stopped being a planet, and the earth, which moves around it, has become one. So you won't be too surprised to hear that the moon is an earth like this one, and that it's very likely inhabited."

"But I've never heard people talk about the moon being inhabited except as a piece of madness and fantasy," she said.

"Maybe it is one," I answered. "I take sides in these matters the way people take sides in civil wars, where nobody knows what's going to happen, so you keep your contacts in the opposing camp and stay on good terms even with your enemies. Personally, though I believe the moon is inhabited, I still live on civil terms with those who don't, and I always keep myself in a position to join their opinion with honor if it gets the upper hand. But until they gain some serious advantage over us, here is what has made me lean toward the people of the moon."

Suppose there had never been any traffic between Paris and Saint-Denis, and a Parisian who had never left his city stood on the towers of Notre-Dame and saw Saint-Denis in the distance. Someone asks him whether he thinks Saint-Denis is inhabited the way Paris is. He'll answer boldly that it isn't. "I can see the people of Paris," he'll say, "but I can't see the people of Saint-Denis. Nobody has ever heard of them." Someone will point out to him that, true enough, when you stand on the towers of Notre-Dame you can't see the people of Saint-Denis, but distance is the reason; that everything you can see of Saint-Denis looks very much like Paris; that Saint-Denis has bell towers, houses, walls; and that it might well resemble Paris in being inhabited, too. None of this will make any impression on my Parisian. He'll stubbornly insist that Saint-Denis isn't inhabited, since he doesn't see anybody there. Our Saint-Denis is the moon, and each of us is that Parisian who has never left his city.

"Oh!" the Marquise interrupted. "You do us wrong. We're not as foolish as your Parisian. Since he can see that Saint-Denis looks just like Paris, he'd have to have lost his mind not to believe it's inhabited. But the moon doesn't look anything like the earth."

"Careful, Madame," I said, "because if the moon has to resemble the earth in every respect, you're obliged to believe it's inhabited."

"I admit there'll be no way out of it," she answered, "and I can see a look of confidence on your face that already frightens me. The two motions of the earth, which I'd never have suspected, have made me timid about everything else. But is it really possible that the earth is luminous, like the moon? Because that's needed for them to resemble each other."

"Alas, Madame," I replied, "being luminous isn't as big a deal as you think. Only the sun has that quality in any real sense. The sun is luminous by itself, by virtue of a special nature it has. The planets only shine because the sun shines on them. The sun sends its light to the moon, and the moon sends it back to us. So the earth must also send the sun's light back to the moon; it's no farther from the earth to the moon than from the moon to the earth."

"But," said the Marquise, "is the earth as good as the moon at sending sunlight back?"

"You still have a leftover esteem for the moon," I said, "that you can't seem to shake. Light is made up of tiny balls that bounce off whatever is solid and fly off in another direction, whereas they pass right through anything that offers them openings in a straight line, like air or glass. So the reason the moon lights us up is that it's a hard, solid body, and it sends these little balls back to us. Now, I don't think you'll deny the earth that same hardness and solidity. So consider what it means to be well placed! Because the moon is far away, we see it only as a luminous body, and we don't know that it's a big mass like the earth. The earth, on the other hand, has the misfortune of being seen from too close, so it looks to us only like a big mass, good for nothing but providing feed for animals, and we don't notice that it shines, because we can't get some distance away from it."

"So it's the same," said the Marquise, "as when we're dazzled by the splendor of people in stations above our own, and we don't see that at bottom they're all extremely alike."

"It's exactly the same thing," I answered. "We want to judge everything, and we're always standing at a bad vantage point. When we want to judge ourselves, we're too close; when we want to judge others, we're too far. The right place to see everyone properly would be somewhere between the moon and the earth. You'd have to be simply a spectator of the world, not an inhabitant."

"I'll never get over the injustice we do the earth," she said, "or our overly favorable prejudice toward the moon, unless you can assure me that the people of the moon don't know their advantages any better than we know ours, and that they take our earth for a star without knowing that where they live is one too."

"On that point," I said, "I can guarantee it. We appear to them to perform our duties as a star quite regularly. It's true they don't see us travel in a circle around them, but that doesn't matter, and here's why. The half of the moon that was turned toward us at the beginning of the world has been turned toward us ever since. It only ever shows us those eyes, that mouth, and the rest of the face that our imagination assembles for it out of the spots it shows us. If the opposite half were turned toward us, other spots, arranged differently, would no doubt make us imagine some other face. That's not to say the moon doesn't turn on itself. It does, in exactly as much time as it takes to go around the earth, that is, in one month. But whenever it makes some part of that turn on itself, and one cheek, say, of this so-called face ought to hide from us and something else appear, it makes exactly the same part of its circle around the earth, and moving to a new vantage point, it shows us that same cheek again. So the moon, which turns on itself with respect to the sun and the other stars, doesn't turn at all with respect to us. All the others seem to it to rise and set in the space of a fortnight, but our earth it always sees hanging in the same spot in the sky. That apparent immobility hardly suits a body that's supposed to pass for a star, but it isn't perfect. The moon has a certain rocking motion that makes a little corner of the face sometimes hide and a little corner of the opposite half show. And on my word, the moon never fails to blame this trembling on us, imagining that we have some pendulum-like motion in the sky, swinging back and forth."

"These planets are just like us," said the Marquise, "always blaming others for what is in ourselves. The earth says, 'It's not me that's turning, it's the sun.' The moon says, 'It's not me that's trembling, it's the earth.' There's a lot of error everywhere."

"I don't advise you to undertake reforming any of it," I answered. "You'd do better to finish convincing yourself that the earth and the moon are perfectly alike. Picture these two great balls hanging in the heavens. You know that the sun always lights half of any round body, while the other half is in shadow. So there's always one half of the earth, and one half of the moon, that is lit by the sun, that is, that has daytime, and another half that's in night. Notice also that just as a ball has less force and speed after it hits a wall and is sent off in another direction, so light is weakened when it has been reflected by a body. That whitish light that comes to us from the moon is the sun's own light, but it can only get from the moon to us by reflection. So it has lost a great deal of the force and vividness it had when it first struck the moon directly, and that brilliant light we receive from the sun, which the earth reflects onto the moon, must be only a whitish light by the time it gets there. So what looks luminous to us on the moon, and lights our nights, is the parts of the moon that have daytime; and the parts of the earth that have daytime, when they're turned toward the parts of the moon that have night, light those up too. It all depends on how the moon and the earth are facing each other.

"In the first days of the month, when we can't see the moon, it's because the moon is between the sun and us, traveling by day along with the sun. Its whole half that has daytime has to be turned toward the sun, and its whole half that has night has to be turned toward us. Of course we can't see that half, since it has no light to show itself with. But that half of the moon, which is in night, is turned toward the half of the earth that has daytime, and it sees us without being seen, and it sees us in the same shape in which we see the full moon. So for the people of the moon it's the full earth, if I may put it that way. Then the moon, moving along on its monthly circle, slips out from under the sun and begins to turn a small corner of its lit half toward us, and there's the crescent. At that point the parts of the moon that have night begin to no longer see the whole half of the earth that has daytime, and for them we're on the wane."

"That's enough," the Marquise said briskly. "I can work out the rest whenever I like. I only need to think for a moment and carry the moon around its monthly circle. I can already see that on the moon they have a month running backward from ours, and I'll bet that when we have a full moon, it's because the moon's whole lit half is turned toward the whole dark half of the earth; that then they don't see us at all, and they count it as new earth. I wouldn't want it held against me that I had you explain something so easy at such length. But the eclipses: how do those work?"

"It's up to you to guess," I said. "When the moon is new, it's between the sun and us, and its whole dark half is turned toward us, who have daytime. You can see that the shadow of that dark half is thrown toward us. If the moon is exactly under the sun, that shadow hides the sun from us, and at the same time it darkens part of the luminous half of the earth that was being looked at by the dark half of the moon. So that's an eclipse of the sun for us during our day, and an eclipse of the earth for the moon during its night. When the moon is full, the earth is between it and the sun, and the whole dark half of the earth is turned toward the whole lit half of the moon. So the earth's shadow is thrown toward the moon. If it falls on the body of the moon, it darkens the luminous half that we see, and it steals the sun from that half, which was having daytime. So that's an eclipse of the moon during our night, and an eclipse of the sun for the moon during the day it was enjoying. The reason there isn't an eclipse every time the moon is between the sun and the earth, or the earth between the sun and the moon, is that those three bodies are often not lined up in an exactly straight line, so the one that ought to cause the eclipse casts its shadow a little to one side of the one that ought to be covered by it."

"I'm amazed," said the Marquise, "that there's so little mystery to eclipses and that everyone doesn't guess the cause."

"Ah, indeed!" I answered. "There are plenty of peoples who, going about it the way they do, won't be guessing it for a long time yet. All through the East Indies they believe that when the sun and moon are eclipsed, it's because a certain dragon with very black claws is stretching them out over those bodies to seize them. And you see the rivers, during that time, covered with the heads of Indians who have gotten into the water up to their necks, because in their view that is a very devout posture and just the thing to persuade the sun and moon to defend themselves well against the dragon. In America they used to be convinced that the sun and moon were angry when they were eclipsed, and heaven knows what people didn't do to make peace with them. And the Greeks, who were so sophisticated, didn't they believe for a long time that the moon was bewitched, and that sorceresses drew it down from the sky to sprinkle a certain harmful foam on the herbs? And we, didn't we get a fine fright only thirty-two years ago, at a certain eclipse of the sun, which, to be fair, was total? Didn't countless people shut themselves up in cellars, and didn't the philosophers who wrote to reassure us write in vain, or nearly so? Did those who had taken refuge in the cellars ever come out?"

"Really," she replied, "all this is too shameful for mankind. There ought to be a decree from the human race forbidding anyone ever to speak of eclipses again, so that the memory of the foolish things that have been done or said on the subject isn't kept alive."

"Then that same decree would have to wipe out the memory of everything," I replied, "and forbid anyone to speak of anything at all, because I don't know of a single thing in the world that isn't a monument to some human folly."

"Tell me one thing, please," said the Marquise. "Are they as afraid of eclipses on the moon as we are here? It would strike me as perfectly ridiculous if the Indians of that country jumped into the water like ours, if the Americans thought our earth was angry with them, if the Greeks imagined that we were bewitched and were going to spoil their herbs, and if, in short, we gave them the same panic that they cause down here."

"I don't doubt it in the least," I answered. "I'd like to know why the gentlemen of the moon would be any stronger-minded than we are. By what right would they frighten us without our frightening them? I'd even think," I added with a laugh, "that since a prodigious number of men have been foolish enough, and still are, to worship the moon, there are people in the moon who worship the earth too, and that we're down on our knees before each other."

"After that," she said, "we might well claim to send influences to the moon and to bring on crises in its sick. But since it takes only a little wit and skill in the people of that country to demolish all these honors we flatter ourselves with, I confess I still fear we may be at some disadvantage."

"Fear nothing," I answered. "It doesn't seem likely that we're the only foolish species in the universe. Ignorance is just the kind of thing to be found everywhere, and though I'm only guessing at the ignorance of the people of the moon, I'm as sure of it as of the most reliable news that comes to us from there."

"And what is this reliable news?" she interrupted.

"It's what is reported to us," I said, "by those scholars who travel there every day with their telescopes. They'll tell you they've discovered lands there, seas, lakes, very high mountains, very deep chasms."

"You surprise me," she said. "I can see how you might discover mountains and chasms on the moon; you'd recognize those, I suppose, by notable unevenness. But how do you tell lands from seas?"

"You tell them apart," I answered, "because water lets part of the light pass through it and sends back less, so from a distance it looks like dark patches, while land, which because of its solidity sends all the light back, shows up as brighter places. The illustrious Monsieur Cassini, the man to whom the heavens are best known in all the world, has discovered on the moon something that splits in two, joins together again, and goes off to lose itself in a sort of well. We can flatter ourselves, with a good deal of likelihood, that it's a river. In short, all these different parts are known well enough that they've been given names, and often the names of scholars. One place is called Copernicus, another Archimedes, another Galileo. There's a Promontory of Dreams, a Sea of Rains, a Sea of Nectar, a Sea of Crises. In fact the description of the moon is so exact that a scholar who found himself there right now would no more get lost than I would in Paris."

"But," she went on, "I'd be very glad to know in more detail what the interior of the country is like."

"It isn't possible," I replied, "for the gentlemen of the observatory to tell you that. You have to ask Astolfo, who was taken to the moon by Saint John. I'm speaking of one of the most delightful follies of Ariosto, and I'm sure you'll be glad to hear it. I admit he'd have done better not to mix Saint John into it, since his name deserves such respect, but still, it's a poetic license that can only be called a bit too playful. Besides, the whole poem is dedicated to a cardinal, and a great pope honored it with a splendid approval that you can see at the front of some editions.

"Here's what happens. Roland, the nephew of Charlemagne, had gone mad because the beautiful Angelica had preferred Medoro to him. One day Astolfo, a brave paladin, found himself in the Earthly Paradise, which was on the summit of a very high mountain, where his hippogriff had carried him. There he meets Saint John, who tells him that to cure Roland's madness, the two of them needed to make a journey to the moon together. Astolfo, who asked nothing better than to see the world, doesn't need to be asked twice, and right away a chariot of fire sweeps the Apostle and the paladin up through the air. Since Astolfo was no great philosopher, he was very surprised to see the moon much bigger than it had looked from the earth. He was more surprised still to see other rivers, other lakes, other mountains, other cities, other forests, and, what would have surprised me too, nymphs hunting in those forests. But the rarest thing he saw on the moon was a valley where you could find everything of every kind that gets lost on earth: crowns and riches and fame, and countless hopes, and the time people give to gambling, and the alms people have distributed after their death, and the verses people present to princes, and the sighs of lovers."

"As for the sighs of lovers," the Marquise interrupted, "I don't know whether they were lost in Ariosto's day, but in our time I don't know any that go to the moon."

"If there were only you, Madame," I said, "you've sent quite a good number there. The moon is so thorough at collecting what's lost down here that everything is there. Ariosto only whispers this to you, but everything is there, right down to the Donation of Constantine. That's the document by which the popes claimed to be masters of Rome and Italy, on the strength of a gift the Emperor Constantine had made them, and the truth is that nobody can say what became of it. But guess what kind of thing you don't find on the moon? Folly. All the folly there ever was on earth is still there, perfectly preserved. On the other hand, it's unbelievable how many lost wits there are on the moon. They're so many vials full of a very subtle liquid that evaporates easily unless it's kept sealed, and on each of these vials is written the name of the person the wits belong to. I believe Ariosto puts them all in a heap, but I prefer to picture them neatly arranged in long galleries. Astolfo was astonished to see that the vials of many people he'd taken for very wise were quite full all the same. As for me, I'm convinced that mine has filled up considerably since I started entertaining you with visions, some philosophical, some poetic. But what consoles me is that it can't be that everything I say to you won't soon get you a little vial on the moon too.

"The good paladin didn't fail to find his own among so many others. He took it, with Saint John's permission, and got all his wits back through his nose, like smelling salts. But Ariosto says he didn't carry them very far, and that he let them go back to the moon through some folly he committed a little later. He didn't forget Roland's vial, which was the object of the trip. He had quite a job carrying it, because that hero's wits were naturally rather heavy, and not a single drop was missing. Then Ariosto, following his praiseworthy habit of saying whatever he pleases, addresses his mistress and says, in very beautiful verse: 'Who will climb to the heavens, my lovely one, to bring back the wits your charms made me lose? I wouldn't complain about that loss, provided it went no further. But if things go on as they've begun, I can only expect to become what I described Roland to be. Still, I don't think I need to go through the air, all the way to the moon, to get my wits back. My wits don't lodge so high. They wander over your eyes and your mouth, and if you'll let me take them back, allow me to gather them up with my lips.'

"Isn't that pretty? For my part, reasoning as Ariosto does, I'd say a person should never lose his wits except through love. You can see they don't go far, and all it takes is lips that know how to recover them. But when you lose them by other roads, as we lose ours, for example, by philosophizing right now, they go straight to the moon, and you can't get them back whenever you like."

"To make up for it," the Marquise replied, "our vials will at least be honorably placed in the philosophical section, whereas our wits might otherwise have gone wandering over someone who didn't deserve them. But to finish taking mine away, tell me, and tell me quite seriously, whether you believe there are men in the moon. Because up to now you haven't spoken to me about it in a very definite way."

"I?" I answered. "I don't believe at all that there are men in the moon. Look how much the face of nature changes between here and China: other faces, other shapes, other customs, and almost other principles of reasoning. Between here and the moon the change must be far greater. When you travel toward certain newly discovered lands, the inhabitants you find there are hardly men. They're animals with human shape, sometimes rather imperfect at that, and almost without any human reason. If someone could make it as far as the moon, it certainly wouldn't be men he'd find there."

"What sort of people would they be, then?" the Marquise asked impatiently.

"Honestly, Madame," I replied, "I have no idea. Suppose it were possible for us to have reason without being men, and suppose we lived on the moon. Would we ever imagine there was down here that strange kind of creature called the human race? Could we picture anything with such foolish passions and such wise thoughts; a life so short and views so long; so much knowledge of things that hardly matter and so much ignorance of the most important; such ardor for freedom and such a leaning toward servitude; such a strong desire to be happy and such a great inability to be? The people of the moon would have to be very clever indeed to guess all that. We see ourselves constantly, and we still haven't guessed how we're put together. People have been reduced to saying that the gods were drunk on nectar when they made men, and that when they came to look at their work soberly, they couldn't help laughing at it."

"So we're quite safe as far as the people of the moon are concerned," said the Marquise. "They won't figure us out. But I wish we could figure them out, because it truly is unsettling to know they're up there, in that moon we can see, and not be able to picture what they're like."

"And why," I answered, "aren't you uneasy about the inhabitants of that great southern land that's still entirely unknown to us? They and we are carried on the same ship, of which they occupy the bow and we the stern. You can see that from stern to bow there's no communication, and that at one end of the ship nobody knows what sort of people are at the other, or what they're doing there. And you'd like to know what goes on in the moon, in that other ship floating far from us through the heavens!"

"Oh!" she replied. "I count the inhabitants of the southern land as known, because they surely must be a lot like us, and in the end we'll get to know them whenever we take the trouble to go and see them. They'll always be there and won't escape us. But those people of the moon, we'll never know them. It's hopeless."

"If I answered you seriously," I said, "that you can't tell what will happen, you'd laugh at me, and no doubt I'd deserve it. Still, I could defend myself fairly well if I wanted to. I have a perfectly ridiculous thought that has an air of plausibility that surprises me; I don't know where it got it from, being as impertinent as it is. I bet I can bring you to admit, against all reason, that there may someday be traffic between the earth and the moon.

"Call to mind the state America was in before it was discovered by Christopher Columbus. Its inhabitants lived in extreme ignorance. Far from knowing the sciences, they didn't even know the simplest and most necessary arts. They went naked, they had no weapons but the bow, they had never conceived that men could be carried by animals. They regarded the sea as a great space forbidden to men, which joined the sky, and beyond which there was nothing. It's true that after spending whole years hollowing out the trunk of a big tree with sharp stones, they would set out on the sea in that trunk and go along the coast, carried by wind and waves. But since this vessel was liable to capsize often, they had to swim at once to catch hold of it again, and, properly speaking, they were always swimming, except for the times when they rested in it. If someone had told them that there was an incomparably more perfect kind of navigation, that you could cross that infinite stretch of water in whatever direction and on whatever course you wanted, that you could stop there without moving in the midst of the stirring waves, that you were master of the speed at which you went, that in short this sea, however vast it was, was no obstacle to communication between peoples, provided only that there were peoples on the other side, you can be sure they'd never have believed it.

"And yet one fine day the strangest and least expected spectacle in the world presents itself to them. Great enormous bodies that seem to have white wings, that fly over the sea, that spew fire on every side, and that come to throw upon the shore unknown men, all covered in iron scales, commanding as they like monsters that run beneath them, and holding in their hands thunderbolts with which they strike down whatever resists them. Where did they come from? Who could have brought them over the seas? Who put fire at their disposal? Are they children of the sun? Because surely they're not men. I don't know, Madame, whether you share the Americans' astonishment as I do, but there can never have been a surprise like it anywhere in the world. After that I won't swear anymore that there can't be traffic some day between the moon and the earth. Would the Americans have believed that there ought to be any between America and Europe, which they didn't even know existed? It's true we'd have to cross that great space of air and sky between the earth and the moon. But did those great seas seem to the Americans any more suited to being crossed?"

"Really," said the Marquise, looking at me, "you're mad."

"Who says otherwise?" I answered.

"But I want to prove it to you," she went on. "I'm not content with your admission. The Americans were so ignorant that they couldn't possibly suspect that roads could be made across seas that vast. But we, who have so much knowledge, we would certainly imagine it if it were actually possible to travel through the air."

"We do more than imagine it possible," I replied. "We're already beginning to fly a little. Several different people have found the secret of fitting themselves with wings that hold them up in the air, of giving them motion, and of getting across rivers. To be sure, it wasn't the flight of an eagle, and these new birds have sometimes paid for it with an arm or a leg, but all the same that represents only the first planks put on the water, which were the beginning of navigation. From those planks it was a long way to big ships that could sail around the world. And yet, little by little, the big ships came. The art of flying is only just being born. It will be perfected, and someday people will go as far as the moon. Do we claim to have discovered everything, or to have brought things to a point where nothing can be added? Come now, let's agree that there's still something left to do for the centuries to come."

"I won't agree," she said, "that people will ever fly, except in a way that breaks their necks right away."

"Well, then," I answered, "if you insist that people will always fly so badly here, they'll fly better on the moon. The inhabitants will be better suited to the trade than we are. It makes no difference whether we go there or they come here. And we'd be like the Americans, who couldn't imagine that anyone could sail, though at the other end of the world people sailed very well."

"So the people of the moon would already have come?" she said, almost angrily.

"The Europeans didn't get to America until after six thousand years," I replied, bursting out laughing. "That's how long it took them to perfect navigation to the point of being able to cross the ocean. The people of the moon perhaps already know how to make short trips in the air. Right now they're practicing. When they're more skilled and experienced, we'll see them, and heaven knows what a surprise that will be."

"You're insufferable," she said, "pushing me to the limit with an argument as hollow as that."

"If you make me angry," I said, "I know what else I'll add to strengthen it. Notice that the world unfolds little by little. The ancients were quite sure that the torrid zone and the frozen zones couldn't be inhabited, because of the excess of heat or cold. And in the time of the Romans, the general map of the earth was hardly larger than the map of their empire, which had a certain grandeur in one sense and showed a great deal of ignorance in another. Yet people were found, both in very hot countries and in very cold ones. There, the world was already enlarged. Then people decided that the ocean covered all the earth except what was known at the time, and that there were no antipodes, because nobody had ever heard of any, and besides, would they have their feet up and their heads down? After that fine piece of reasoning, they discovered the antipodes. A new revision of the map, a new half of the earth. You take my meaning, Madame. Those antipodes, found against all expectation, should teach us to be cautious in our judgments. The world may finish unfolding for us, and one day we'll know even the moon. We're not there yet, because the whole earth isn't discovered, and apparently all this has to happen in order. When we've come to know our own home well, we'll be allowed to get to know that of our neighbors, the people of the moon."

"Truly," said the Marquise, looking at me closely, "you're so deep on this subject that it can't be that you don't believe in earnest what you're saying."

"I'd be very sorry if I did," I answered. "I only want to show you that a chimerical opinion can be defended well enough to embarrass a person of wit, but not well enough to persuade her. Only the truth persuades, even without needing to appear with all its proofs. It enters the mind so naturally that when you learn it for the first time, it seems you're only remembering it."

"Ah, you relieve me!" said the Marquise. "Your false reasoning was troubling me, and I feel more fit to go to bed peacefully, if you'll agree that we retire."

The Third Evening: The World of the Moon, and the Other Planets Inhabited Too

During the day the Marquise tried to talk me into continuing our conversations, but I told her that we shouldn't entrust daydreams like these to anyone but the moon and the stars, since they were, after all, what the daydreams were about. Naturally, we went to the Park that evening. It was becoming a place set apart for our learned conversations.

"I have some news for you," I told her. "The moon I described yesterday, the one that by all appearances was inhabited, may well not be. I've thought of something that puts its people in danger."

"I won't stand for that," she answered. "Yesterday you had me all prepared to see these people arrive here any day now, and today they wouldn't even exist? You won't make a fool of me like that. You made me believe in the people of the moon. I got over my reluctance, and I'm going to believe in them."

"You're moving fast," I said. "With beliefs of this kind, you should give only half your mind to them and keep the other half free, so the opposite can be admitted if need be."

"Proverbs don't satisfy me," she replied. "Let's get to the point. Shouldn't we reason about the moon the way we would about St. Denis?"

"No," I said, "the moon doesn't resemble the earth as closely as St. Denis resembles Paris. Here is the problem. The sun lifts vapors and exhalations from the earth and the waters. They rise into the air to a certain height, gather there, and form clouds. These clouds hang there and drift irregularly around our globe, shading one country and then another. Anyone looking at the Earth from far away would often notice changes on its surface, because a large country covered by clouds would be a dark spot, and would grow brighter as soon as the clouds cleared off. You would see spots that changed place, or merged in different ways, or disappeared altogether. So you would see the same changes on the surface of the moon, if it had clouds around it. But quite the opposite: all its spots are fixed, its bright places are always bright, and that's the trouble. By that reckoning, the sun raises no vapors or exhalations from the moon. So the moon is a body infinitely harder and more solid than our earth. The earth's finest particles break away easily from the rest and rise as soon as heat sets them moving. The moon must be some heap of rocks and marble where nothing evaporates. And evaporation happens so naturally and so necessarily wherever there is water that there can be no water where it doesn't happen. So who are the inhabitants of these rocks that can produce nothing, in a country with no water?"

"What?" she cried. "Don't you remember assuring me that there were seas on the moon that you could make out from here?"

"That's only a guess," I answered, "and I'm sorry to say so. Those dark places we take for seas may just be big hollows. From this distance, we're allowed to miss the mark a little."

"But will that be enough to make us give up the people of the moon?" she said.

"Not entirely, Madame," I replied. "We won't decide either for them or against them."

"I'll admit my weakness," she said. "I'm not capable of such perfect indecision. I need to believe. Settle me quickly on an opinion about the people of the moon. Either we keep them or we wipe them out for good, and we never speak of it again. But let's keep them, if we possibly can. I've grown fond of them, and I'd have trouble losing them."

"Then I won't leave the moon empty," I said. "We'll repopulate it to please you. True, since the pattern of the moon's spots never changes, we can't believe it has clouds around it, shading first one part and then another. But that doesn't mean it gives off no vapors or exhalations. The clouds we see floating in the air are nothing but exhalations and vapors. When they left the earth they were in pieces too small to see, and then a little higher up they ran into a cold that squeezed them together and made them visible by joining their parts. After that they are big clouds floating in the air, foreign bodies there, until they fall back as rain. But those same vapors and exhalations sometimes stay scattered enough to be imperceptible, and they gather only into very fine dews that we never see falling from any cloud. So I suppose that vapors do come out of the moon. In fact they must. It isn't believable that the moon is a mass whose parts are all equally solid, all equally at rest beside one another, all incapable of being changed by the action of the sun. We don't know any body like that. Even marble isn't. Everything, however solid, changes and wears, either through the secret, invisible motion inside it or through the motion it receives from outside. But the moon's vapors won't gather around it in clouds and fall back on it as rain. They'll form only dew. All that takes is for the air around the moon (and presumably the moon has its own air, as our earth has its own) to be a little different from our air, and the moon's vapors a little different from the earth's, which is more than merely likely. On that footing, since matter is arranged differently on the moon than on the earth, the effects have to be different. But that doesn't matter. The moment we've found an inner motion in the moon's parts, whether produced by outside causes or not, its inhabitants are alive again, and we have the basic supply they need to live on. That will give us fruits, grain, water, and whatever else we want. I mean fruits, grain, and water in the moon's style, which I openly admit I don't know, all of it suited to the needs of its inhabitants, whom I don't know either."

"In other words," said the Marquise, "all you know is that everything is fine, without knowing how it is. That's a lot of ignorance on very little knowledge. But we'll have to console ourselves. I'm lucky enough that you've given the moon its inhabitants back. I'm even quite pleased that you give it an air of its own around it. From now on, without that, a planet would seem too bare to me."

"These two different airs," I went on, "help keep the two planets from communicating. If it were only a matter of flying, who knows, as I said yesterday, whether people won't fly quite well someday? I admit there isn't much sign of it. The great distance from the moon to the earth would still be a difficulty to overcome, and a considerable one. But even if that weren't there, it wouldn't be possible to pass from the air of one into the air of the other. Water is the air of fish. They never pass into the air of birds, nor birds into the air of fish. It isn't distance that stops them. Each of them is imprisoned by the air it breathes. Our own air, we find, is mixed with vapors thicker and coarser than the moon's. By that reckoning, an inhabitant of the moon who reached the edge of our world would drown the moment he entered our air, and we would see him fall dead to the earth."

"Oh, how I'd love it," cried the Marquise, "if there were some great shipwreck that scattered a good number of those people down here, so we could go and examine their extraordinary shapes at our leisure!"

"But suppose," I replied, "they were clever enough to sail on the outer surface of our air, and from there, out of curiosity to see us, they fished for us like fish. Would you like that?"

"Why not?" she answered, laughing. "For my part, I'd climb into their nets of my own accord, just for the pleasure of seeing the people who had caught me."

"Bear in mind," I said, "that you'd arrive at the top of our air quite sick. It isn't breathable for us throughout its whole extent, far from it. They say it's already almost unbreathable at the top of certain mountains. And I'm surprised that the people who are foolish enough to believe that bodily spirits live in the purest air don't also say why those spirits visit us so rarely and so briefly. It's that few of them know how to dive, and even those can only make very short plunges down to the bottom of this thick air where we live. So there are plenty of natural barriers to keep us from leaving our world and entering the moon's. For our consolation, let's at least try to guess what we can about that world. I believe, for example, that the sky, the sun, and the other heavenly bodies must look a different color there than they do to us. All those objects reach us only through a kind of natural spyglass that changes them for us. That spyglass is our air, mixed as it is with vapors and exhalations, and it doesn't reach very high. Some modern thinkers claim that air is blue in itself, just like sea water, and that in both cases the color shows only at great depth. The heavens, they say, where the fixed stars are set, have no light of their own, and so they should look black. But we see them through the air, which is blue, and so they look blue. If that's true, the rays of the sun and stars can't pass through the air without taking on a little of its color and giving up that much of their own. But even if the air weren't colored in itself, it's certain that through a thick fog the light of a torch seen from a little way off looks all reddish, though that isn't its true color. Our air is nothing but a thick fog, and it must alter the true color of the sky, the sun, and the stars. Only the celestial matter could bring us light and colors in all their purity, just as they are. So, since the air of the moon is of a different nature from ours, either it is tinted some other color in itself, or at the very least it is a different fog that alters the colors of the heavenly bodies in a different way. In short, for the people of the Moon, the spyglass through which they see everything has been changed."

"That makes me prefer our home to the moon," said the Marquise. "I can't believe the arrangement of heavenly colors is as beautiful there as it is here. Suppose, if you like, a red sky and green stars. The effect isn't as pleasant as gold stars on blue."

"To hear you," I said, "one would think you were matching a dress or a piece of furniture. But believe me, nature has a great deal of wit. Leave it to her to invent a color scheme for the moon, and I guarantee it will be well thought out. She won't have failed to vary the spectacle of the universe for each different point of view, and to vary it in a way that is always pleasing."

"I recognize her cleverness," the Marquise broke in. "She saved herself the trouble of changing the objects for each point of view. She changed only the spyglasses, and she gets the credit for all this variety without having paid for it. With a blue air she gives us a blue sky, and perhaps with a red air she gives a red sky to the people of the Moon, yet it's always the same sky. It seems to me that she has also put certain spyglasses into our imaginations, through which we see everything, and which change objects a great deal from one person to the next. Alexander saw the Earth as a fine piece of ground, just right for founding a great empire. Céladon saw it only as the home of Astrée. A philosopher sees it as a big planet traveling through the heavens, all covered with madmen. I don't think the view changes more from the earth to the moon than it does here from one imagination to another."

"The change of view is more surprising among our imaginations," I replied, "because it's only the same objects that are seen so differently. On the moon, at least, you can see other objects, or fail to see some that we see here. Perhaps in that country they know neither dawn nor twilight. The air that surrounds us and rises above us receives rays that couldn't otherwise reach the earth. And because it is quite coarse, it holds back a portion of them and sends them down to us, though they weren't naturally meant for us. So dawn and twilight are a favor nature does us. It's a light we regularly shouldn't have, and she gives it to us over and above what we're owed. But on the moon, where the air is presumably purer, it may well not be so good at sending down the rays it receives before the sun rises or after it sets. So the poor inhabitants don't have this light of favor, which by growing stronger little by little would ease them pleasantly into the sun's arrival, or by fading away shade by shade would get them used to its loss. They're in deep darkness, and then all at once it's as if someone drew a curtain, and their eyes are struck by the full blaze of the sun. They're in a bright, dazzling light, and then all at once they've dropped into deep darkness. Day and night aren't joined by any middle ground that shares in both. The rainbow is another thing the people of the moon lack. If dawn is an effect of the coarseness of the air and its vapors, the rainbow forms in rain that falls under certain conditions, and we owe the most beautiful things in the world to those that are the least beautiful themselves. Since around the moon there are neither vapors coarse enough nor rain clouds, farewell to the rainbow along with the dawn. And what will the beauties of that country be compared to? What a source of comparisons lost!"

"I wouldn't miss those comparisons much," said the Marquise, "and I think the moon's people are rewarded well enough for having neither dawn nor rainbow. For the same reason they can't have lightning or thunder either, since those also form in clouds. They have fine days, always clear, when they never lose sight of the sun. They have no nights when all the stars don't show. They know nothing of storms or tempests, or of anything that seems an effect of the anger of heaven. Do you think they're so much to be pitied?"

"You make the moon sound like an enchanted place," I answered. "Still, I don't know whether it's so delightful to have an ardent sun over your head all the time, for days worth fifteen of ours, with no cloud to temper its heat. Maybe that's why nature has dug a kind of well into the moon, big enough for our telescopes to spot. They aren't valleys between mountains. They're hollows seen in the middle of certain flat places, and there are a great many of them. Who knows whether the people of the Moon, made uncomfortable by the sun's perpetual heat, don't take refuge in these great wells? Perhaps they don't live anywhere else, and that's where they build their cities. We see here that underground Rome is bigger than the Rome above ground. You'd only have to take the second away, and what was left would be a city in the moon's style. A whole people lives in a well, and from one well to the next there are underground roads so the peoples can communicate. You laugh at this vision. I agree with all my heart. Yet, to speak to you quite seriously, you could be wrong sooner than I. You think the people of the moon must live on the surface of their planet because we live on the surface of ours. It's exactly the opposite. Since we live on the surface of our planet, they may well not live on the surface of theirs. Between here and there, everything must be very different."

"It doesn't matter," said the Marquise. "I can't bring myself to let the people of the moon live in perpetual darkness."

"You'd have even more trouble," I said, "if you knew that a great philosopher of antiquity made the moon the home of the souls who have earned a blessed afterlife here. All their happiness consists in hearing the harmony the heavenly bodies make with their motions. But he claims that when the moon falls into the earth's shadow, they can no longer hear this harmony. Then, he says, these souls cry out like people in despair, and the moon hurries as fast as it can to pull them out of so unpleasant a spot."

"Then we should see the blessed of the moon arriving here," she replied, "since presumably ours are sent up there. And on both planets they think they've done enough for the happiness of souls by moving them to another world."

"Seriously," I said, "it wouldn't be a small pleasure to see several different worlds. This voyage delights me a great deal even when I make it only in imagination. What would it be if we made it in fact? It would be far better than going from here to Japan, which means crawling with great effort from one point on the earth to another, only to see more human beings."

"Well, then," she said, "let's take the voyage of the planets as best we can. Who's stopping us? Let's go and station ourselves at all those different points of view, and from there look at the universe. Is there nothing left for us to see on the moon?"

"That world isn't used up yet," I answered. "You remember that the two motions by which the moon turns on itself and goes around us are equal, so that one always gives back to our eyes what the other would otherwise take away, and so it always shows us the same face. So only that half of the moon can see us. And since the moon can be considered as not turning on its center in relation to us, the half that sees us sees us always fixed at the same place in the sky. When it's in night, and those nights are worth fifteen of our days, it first sees a small corner of the earth lit up, then a larger one, and almost hour by hour the light seems to spread across the face of the earth until at last it covers all of it. Whereas for us, the same changes seem to happen on the moon only from one night to the next, because we lose sight of it for a long time. I'd love to be able to guess the bad reasoning that the philosophers of that world come up with about our earth looking motionless to them, when all the other heavenly bodies rise and set over their heads in fifteen days. They probably put this stillness down to its size, for it's sixty times bigger than the moon, and when poets want to praise idle princes, I have no doubt they use the example of this majestic repose. Yet it isn't perfect repose. From inside the moon you can see our earth turning on its center quite clearly. Picture our Europe, our Asia, our America coming into view one after another, small and shaped differently, much as we see them on maps. How new that sight must seem to travelers who cross from the half of the moon that never sees us to the half that always does! And how careful people must have been not to believe the reports of the first travelers who spoke of it when they got back to that great country where we're unknown!"

"It occurs to me," said the Marquise, "that people make sort of pilgrimages from that country to the other to come and look at us, and that there are honors and privileges for those who have seen the big planet once in their lives."

"At least," I said, "those who see it have the privilege of being better lit during their nights. Living on the other half of the Moon must be far less comfortable in that respect. But, Madame, let's continue the voyage we set out to make from planet to planet. We've visited the Moon carefully enough. Leaving the moon and heading toward the sun, we come to Venus. On Venus I take up St. Denis again. Venus turns on itself and around the sun like the moon. With telescopes we can see that Venus, like the moon, is sometimes a crescent, sometimes waning, sometimes full, depending on its different positions in relation to the earth. The moon, by all appearances, is inhabited. Why wouldn't Venus be too?"

"But," the Marquise interrupted, "by always saying 'why not?' you're going to put inhabitants on every planet!"

"No doubt about it," I replied. "That 'why not' has a power that will populate everything. We see that all the planets are of the same nature. They're all opaque bodies that receive light only from the sun, that bounce it back and forth to one another, and that have the same motions. So far everything is equal. Yet we would have to imagine that these great bodies were made to be uninhabited, that this was their natural condition, and that there was an exception in favor of the earth alone. Whoever wants to believe it can. As for me, I can't bring myself to."

"You seem quite firm in your opinion these last few moments," she said. "A minute ago I saw the moon about to be deserted, and you didn't seem to care much. Now, if anyone dared tell you that not all the planets are as inhabited as the earth, I can see you'd lose your temper."

"It's true," I answered, "that at the moment when you caught me off guard, if you had contradicted me about the inhabitants of the planets, not only would I have defended them, I think I would have told you what they looked like. There are moments for believing, and I never believed so well as in that one. Even now, when I'm a little cooler, I still find it would be very strange if the earth were as inhabited as it is and the other planets not at all. Don't imagine that we see everything that lives on the earth. There are as many species of invisible animals as visible ones. We see everything from the elephant down to the cheese mite, and there our sight ends. But from the cheese mite on, there begins an infinite multitude of animals to which the mite is an elephant, and which our eyes can't make out without help. With lenses, people have seen very small drops of rain water, or vinegar, or other liquids full of little fish or little snakes that no one would ever have suspected lived there. And some philosophers believe that the taste these liquids give us is the stinging of these little animals on the tongue. Mix certain things into some of these liquids, or set them in the sun, or let them go bad, and right away there are new species of little animals.

"Many bodies that look solid are hardly more than heaps of these imperceptible animals, which find as much freedom as they need to move about in them. A tree leaf is a little world inhabited by invisible worms. To them it seems immensely large. They know mountains and abysses there, and from one side of the leaf to the other they have no more communication with the other worms living on it than we have with our antipodes. All the more, it seems to me, will a big planet be an inhabited world. People have found, even inside certain very hard kinds of stone, countless little worms lodged everywhere in tiny empty spaces too small to feel, living only on the substance of the stone they gnawed. Imagine how many of these little worms there were, and for how many years they lasted on a piece the size of a grain of sand. On that example, even if the moon were only a heap of rocks, I would have its inhabitants gnaw it away rather than put none there. In short, everything is alive, everything is animated. Put together all these newly discovered species of animals, and even all those that we can easily imagine are still to be discovered, along with those that have always been seen, and you'll surely find that the earth is well populated, and that nature has scattered animals here so generously that she didn't trouble herself about whether we saw even half of them. Will you believe that after she pushed her fertility here to excess, she was so barren toward all the other planets that she produced nothing alive on them?"

"My reason is quite well convinced," said the Marquise, "but my imagination is overwhelmed by the endless multitude of inhabitants on all these planets, and embarrassed by the variety we have to establish among them. I can see that nature, being an enemy of repetition, must have made them all different. But how can we picture all that?"

"It isn't for the imagination to claim it can picture it," I answered. "It can't go any farther than the eyes. All you can do is grasp, in a kind of general view, the variety that nature must have put among all these worlds. All faces follow one model in general. But the faces of two great nations, say Europeans and Africans or Tartars, seem to be made on two particular models, and you would still have to find the model for the faces of each family. What a secret nature must have had, to vary in so many ways a thing as simple as a face! In the universe we're only like a small family, all of whose faces look alike. On another planet there's another family, whose faces have a different look.

"Presumably the differences grow as you move farther away. Anyone who saw an inhabitant of the Moon and an inhabitant of the earth side by side would notice that they came from two worlds closer to each other than an inhabitant of the earth and an inhabitant of Saturn. Here, for example, we have the use of speech. Elsewhere they talk only by signs. Farther on they don't talk at all. Here, reasoning is formed entirely by experience. Elsewhere experience adds very little to it. Farther on, the old know no more than the children. Here we torment ourselves more about the future than the past. Elsewhere they torment themselves more about the past than the future. Farther on they torment themselves about neither, and those people are perhaps not the unhappiest. It's said that we may be missing a sixth natural sense, which would teach us many things we don't know. This sixth sense is presumably in some other world, where one of the five we have is missing. Maybe there really are a great many natural senses, but in the division we made with the inhabitants of the other planets, only five fell to us, and we're content with them because we know of no others. Our sciences have certain limits that the human mind has never been able to pass. There is a point where they suddenly fail us, and the rest is left for other worlds, where something we know is unknown. This planet enjoys the pleasures of love, but it is always devastated in several of its parts by the furies of war. On another planet they enjoy eternal peace, but in the midst of that peace they know no love, and they're bored. In short, what nature does on a small scale among men in handing out happiness and talents, she has surely done on a large scale among worlds. And she will certainly have remembered to use that marvelous secret she has, of making everything different and, at the same time, evening things out with compensations.

"Are you satisfied, Madame?" I added. "Have I opened a big enough field for your imagination to work in? Can you already see some inhabitants of the planets?"

"Alas, no," she answered. "All this you tell me is marvelously empty and vague. I see only a great something-or-other where I see nothing. I need something more definite, more marked."

"Well, then," I said, "I'm going to resolve to hide nothing of the most particular things I know. It's something I have from a very good source, and you'll agree once I've named my authorities. Listen, please, with a little patience. It will take a while.

"There is a planet, which I won't name yet, with inhabitants who are very lively, very hard-working, very skillful. They live only by plunder, like some of our Arabs, and that is their one vice. Otherwise, they're in perfect agreement among themselves, working tirelessly and zealously together for the good of the state, and above all their chastity is beyond compare. True, there isn't much merit in it for them, since they're all sterile. There is no sex among them."

"But," the Marquise interrupted, "didn't you suspect that someone was making fun of you by giving you this fine report? How would the nation continue?"

"No one was making fun of me," I said, with great coolness. "Everything I tell you is certain, and the nation does continue. They have a queen who doesn't lead them to war, who hardly seems to meddle in the affairs of state, and whose whole royalty consists in being fertile, but with an astonishing fertility. She has thousands of children, and indeed she does nothing else. She has a great palace divided into an endless number of rooms, each with a cradle prepared for a little prince, and she goes to give birth in each of these rooms one after another, always accompanied by a large court that applauds her for this noble privilege, which she enjoys to the exclusion of all her people.

"I understand you, Madame, without your saying a word. You're asking where she found lovers or, to put it more politely, husbands. There are queens in the East and in Africa who openly keep harems of men. This one apparently has one, but she makes a great mystery of it, and if that shows more modesty, it also shows less dignity. Among these Arabs, who are always busy, whether at home or abroad, you can pick out a very few foreigners who look very much like the natives of the country in shape, but who in other respects are very lazy, never go out, do nothing, and by all appearances wouldn't be tolerated among an extremely active people if they weren't set aside for the queen's pleasure and the important ministry of propagation. Indeed, if in spite of their small number they are the fathers of the ten thousand children, more or less, that the queen brings into the world, they deserve to be excused from every other job. And what makes it plain that this has been their only function is that as soon as it is fully carried out, as soon as the queen has had her ten thousand births, the Arabs kill these wretched foreigners, who have become useless to the state, without mercy."

"Is that all?" said the Marquise. "Thank God. Let's get back to common sense a little, if we can. Honestly, where did you get all that romance? What poet supplied it to you?"

"I tell you again," I answered, "that it isn't a romance. All this happens right here on our earth, before our eyes. You look astonished. Yes, before our eyes. My Arabs are only bees, since I have to tell you."

Then I taught her the natural history of bees, of which she knew hardly more than the name. After that I went on: "You see, then, that by merely transferring to other planets things that happen on ours, we would imagine oddities that would seem extravagant and would nevertheless be very real. And we would imagine them without end, because, I'll have you know, Madame, the history of insects is full of them."

"I believe it easily," she answered. "Even silkworms alone, which I know better than I knew bees, would give us some quite surprising peoples. They would change form so completely that they would no longer be the same at all, crawl during one part of their lives and fly during the other, and what else? A hundred thousand other marvels that will make up the different characters and different customs of all these unknown inhabitants. My imagination is working on the plan you've given me, and I'm even going so far as to compose faces for them. I couldn't describe them to you, but I do see something."

"As for those faces," I replied, "I advise you to leave them to the dreams you'll have tonight. We'll see tomorrow whether they served you well, and whether they taught you what the inhabitants of some planet look like."

The Fourth Evening: The Worlds of Venus, Mercury, Mars, Jupiter and Saturn

The dreams weren't any help. They kept showing us something that looked just like what you see around here. I had reason to scold the Marquise the way certain peoples scold us when they look at our paintings, since they only ever paint bizarre, grotesque things. "Well, well!" they say. "That's just like people. There's no imagination in it." So we had to resign ourselves to not knowing what the inhabitants of all those planets look like, and be content to guess what we could as we continued the tour of the worlds that we had begun. We had reached Venus.

"We're quite sure," I told the Marquise, "that Venus turns on its own axis, but we don't know exactly how long that takes, and so we don't know how long its days last. Its years are only about eight months long, since that's how long it takes to go around the Sun. It's about the size of the Earth, so the Earth looks to Venus just as big as Venus looks to us."

"I'm delighted to hear it," said the Marquise. "The Earth can be the shepherd's star for Venus, and the mother of loves, just as Venus is for us. Those names only suit a small planet that's pretty, clear, bright, and has a gallant air about it."

"I agree," I said. "But do you know what makes Venus so pretty from far away? It's that it's quite hideous up close. Telescopes have shown that it's nothing but a heap of mountains, much taller than ours, very pointed, and apparently very dry. That kind of surface is the best possible one for a planet to throw light back with plenty of brilliance and sparkle. Our Earth, whose surface is very smooth compared with Venus's, and partly covered with seas, may well not look so lovely from a distance."

"That's too bad," said the Marquise, "because it would surely be an honor and a pleasure for the Earth to preside over the love affairs of the people of Venus. Those people must understand gallantry."

"Oh, without a doubt," I answered. "The common folk of Venus are nothing but Céladons and Silvandres, the lovesick shepherds of the old romances, and their everyday conversations are as good as the finest in Clélie. The climate is very favorable to love. Venus is closer to the Sun than we are, and gets brighter light and more warmth from it. It sits at about two thirds of the distance from the Sun to the Earth."

"Now I see," the Marquise broke in, "what the people of Venus are like. They're like the Moors of Granada: a small dark people, sunburned, full of wit and fire, always in love, writing verses, loving music, inventing festivals, dances and tournaments every day."

"Allow me to tell you, Madame," I replied, "that you hardly know the people of Venus. Next to them, your Moors of Granada would have been Laplanders and Greenlanders for coldness and dullness."

"But what about the people of Mercury?" I went on. "They're more than twice as close to the Sun as we are. They must be mad with liveliness. I imagine they have no memory; that they never reflect on anything, that they act at random and on sudden impulses, and that Mercury is, in short, the universe's madhouse. They see the Sun nine times bigger than we see it. It sends them such strong light that if they were here, they'd take our finest days for the faintest twilight, and maybe couldn't even make out objects. The heat they're used to is so extreme that the heat we get here in the depths of Africa would make them shiver. Presumably our iron, our silver and our gold would melt at their place, and they'd only ever see them as liquids, just as we usually see water only as a liquid, even though at certain times of year it's a very solid body. The people of Mercury wouldn't suspect that in another world those liquids, which perhaps make up their rivers, are among the hardest bodies we know of.

"Their year is only three months long. We don't know how long their day lasts. Mercury is so small and so close to the Sun, lost almost all the time in its rays, that it slips past all the skill of the astronomers, and no one has yet gotten a good enough hold on it to observe how it turns on its center. But its inhabitants need it to finish that turn quickly, because, scorched as they are by a great blazing stove hanging over their heads, they must long for night. During that time they're lit by Venus and by the Earth, which must look fairly large to them. As for the other planets, since they lie beyond the Earth toward the firmament, Mercury sees them smaller than we do and gets very little light from them."

"I'm not so much moved," said the Marquise, "by what the people of Mercury lose there, as by the discomfort they suffer from all that heat. I'd like us to give them some relief. Let's give Mercury long, heavy rains to cool it off, like the ones they say fall here in hot countries for four months at a stretch, right in the hottest seasons."

"That could be," I said, "and we can cool Mercury down another way, too. There are regions of China that ought to be very hot given where they lie, and yet they have bitter cold in July and August, so cold that the rivers freeze. That's because those lands are rich in saltpeter. Its vapors are very cold, and the force of the heat draws them out of the ground in great quantities. If you like, Mercury can be a little planet made entirely of saltpeter, and the Sun will draw the cure for the harm it might do from Mercury itself. What's certain is that nature can only make people live where they can live, and then habit, joined with not knowing anything better, comes along and makes them live there happily. So Mercury could even do without the saltpeter and the rains."

"After Mercury, as you know, comes the Sun. There's no way to put inhabitants there. We lack the 'why not' that we had for the others. From the fact that the Earth is inhabited, we judge that other bodies of its kind must be too. But the Sun isn't a body of the same kind as the Earth, or as the other planets. It's the source of all the light that the planets merely throw back and forth to each other after receiving it from him. They can trade it among themselves, so to speak, but they can't produce it. He alone draws this precious substance out of himself. He pushes it out with force in every direction, and from there it comes back whenever it meets anything solid. From one planet to another, long broad streams of light are spread out, crossing, passing through and interlacing in a thousand different ways, and forming wonderful fabrics of the richest material in the world. That's why the Sun is placed at the center, which is the most convenient spot from which to share it out evenly and bring everything to life with his warmth.

"So the Sun is a body of its own kind. But what kind? It's hard to say. People had always believed it was a very pure fire, but they were set straight at the beginning of this century, when spots were noticed on its surface. Shortly before, new planets had been discovered, which I'll tell you about, and the whole world of philosophers had its mind full of nothing else. New planets had, in short, become fashionable. So people immediately decided that the spots were planets too, that they moved around the Sun, and that they necessarily hid part of it from us as they turned their dark half toward us. Already the learned were paying court to the princes of Europe with these so-called planets. Some named them after one prince, some after another, and there might well have been a quarrel among them over who would keep the spots, so as to name them as he pleased."

"I don't like that at all," the Marquise interrupted. "The other day you told me that the different parts of the Moon had been given the names of scholars and astronomers, and I was very pleased. Since princes take the Earth for themselves, it's only fair that scholars reserve the heavens and rule there, but they shouldn't let anyone else in."

"Allow them, at least," I answered, "to pledge some star or some part of the Moon to princes if the need arises. As for the spots on the Sun, they could make no use of them. It turned out that they weren't planets at all but clouds, smoke and scum rising on the Sun. Sometimes there are a great many, sometimes only a few, sometimes they all vanish. Sometimes several come together, sometimes they split apart, sometimes they're brighter, sometimes darker. There are times when you see plenty of them, and other times, quite long ones, when none appear. You'd think the Sun was a liquid substance, molten gold according to some, boiling ceaselessly and producing impurities that the force of its motion throws up onto its surface. There they burn away, and then others form.

"Imagine what foreign bodies these are. One of them is seventeen hundred times bigger than the Earth, because you should know that the Earth is more than a million times smaller than the globe of the Sun. Judge from that how much of this molten gold there is, or how vast this great sea of light and fire is. Others say, and with some plausibility, that the spots, at least most of them, aren't new productions that dissolve after a while, but big solid masses of very irregular shape, always present, which sometimes float on the liquid body of the Sun and sometimes sink into it, wholly or partly, and show us different points or humps depending on how deep they sink and which side they turn toward us. Perhaps they're part of some great pile of solid matter that feeds the Sun's fire.

"In any case, whatever the Sun may be, it doesn't look at all suited to being lived on. That's a pity, though. It would be a fine place to live. You'd be at the center of everything, and you'd see all the planets circling regularly around you. We, by contrast, see all sorts of oddities in their courses, and they only appear because we aren't in the right place to judge them properly, which is to say at the center of their motion. Isn't that a shame? There's only one place in the world from which the study of the heavens could be extremely easy, and in that very place there's nobody."

"You're not thinking," said the Marquise. "Anyone in the Sun would see nothing, neither planets nor fixed stars. Doesn't the Sun wipe everything out? Its inhabitants would be the ones with good reason to think they were alone in all of nature."

"I admit I was mistaken," I replied. "I was only thinking of where the Sun sits, not of the effect of its light. But since you correct me so promptly, you'll let me tell you that you're mistaken too. The inhabitants of the Sun wouldn't even see it. Either they couldn't stand the force of its light, or they couldn't take it in, for lack of being at some distance from it. All things considered, the Sun would be a home for the blind. Once again, it's not made to be lived on.

"But shall we go on with our tour of the worlds? We've arrived at the center, which is always the lowest place in anything round. I'll tell you in passing that to get here we've traveled thirty-three million leagues. Now we have to turn back and climb up again. We'll pass Mercury, Venus, the Earth and the Moon again, all planets we've already visited. Then Mars comes up. There's nothing remarkable about Mars that I know of. Its days are a little over half an hour longer than ours, and its year is two of our years, minus a month and a half. It's five times smaller than the Earth, and it sees the Sun a bit smaller and duller than we do. All in all, Mars isn't really worth stopping for.

"But what a pretty thing Jupiter is, with its four moons, or satellites! They're four small planets which circle Jupiter as our Moon circles us, while Jupiter goes around the Sun in twelve years."

"But," the Marquise interrupted, "why are there planets that go around other planets that are no better than they are? Seriously, it seems to me it would be more regular and uniform if all the planets, big and small, had just the one motion around the Sun."

"Ah, Madame," I replied, "if you knew what Descartes's vortices are, those vortices whose name is so terrible and whose idea is so pleasant, you wouldn't talk like this."

"Even if my head should spin," she said, laughing, "it's a fine thing to know what vortices are. Go ahead and finish driving me mad. I'm holding nothing back anymore, I have no restraint left where philosophy is concerned. Let the world talk, and let's give ourselves to the vortices."

"I never knew you capable of such transports," I said. "It's a pity they have only vortices for their object. What we call a vortex is a mass of matter whose parts are detached from one another and all move in the same direction. They're allowed some small motions of their own meanwhile, as long as they always follow the general motion. So a whirlwind is an endless number of tiny particles of air, all turning in a circle together and wrapping up whatever they meet. You know that the planets are carried along in the celestial matter, which is of prodigious subtlety and agitation. All this great mass of celestial matter, from the Sun out to the fixed stars, turns in a circle. It carries the planets along with it and makes them all turn in the same direction around the Sun, which sits at the center, but in longer or shorter times depending on how far they are from it. Even the Sun turns on its own axis, because it sits right in the middle of all this celestial matter. You'll notice, in passing, that even if the Earth were in the Sun's place, it still couldn't help turning on itself.

"That's the great vortex, of which the Sun is the master, so to speak. But at the same time, the planets form small vortices of their own, in imitation of the Sun's. Each of them, while turning around the Sun, also turns around itself, and makes a certain amount of this celestial matter turn around it in the same direction. That matter is always ready to follow whatever motions you want to give it, as long as they don't pull it away from its general motion. That's the planet's own vortex, and the planet pushes it as far as the force of its motion can reach. If some planet smaller than the one that rules there falls into this little vortex, it's swept up by the larger one and inevitably forced to circle around it, and the whole assembly, the big planet, the small one and the vortex that holds them both, goes right on turning around the Sun.

"That's how, at the beginning of the world, we came to be followed by the Moon: it happened to lie within our vortex, and very conveniently for us. Jupiter, whom I was beginning to tell you about, was luckier, or more powerful, than we were. There were four small planets in his neighborhood, and he made all four his subjects. And we, who are a principal planet, do you think we'd have been one if we'd landed near him? He's a thousand times bigger than we are. He'd have swallowed us up in his vortex without any trouble, and we'd be just a Moon in his service, instead of having one in ours. So true it is that the mere chance of where you're placed often decides the whole fortune you'll have."

"And who guarantees," said the Marquise, "that we'll always stay where we are? I'm starting to fear that we'll do something foolish and get close to a planet as enterprising as Jupiter, or that he'll come toward us to swallow us up. It seems to me that with all this great motion you say the celestial matter has, it ought to stir the planets about irregularly, sometimes bringing them together, sometimes moving them apart."

"We could as easily gain as lose by it," I answered. "Perhaps we'd go and bring Mercury or Mars under our rule, since they're smaller planets and couldn't resist us. But we have nothing to hope for or fear. The planets stay where they are. New conquests are forbidden to them, as they once were to the kings of China. You know that when you pour oil onto water, the oil floats on top. If you put an extremely light object on those two liquids, the oil will hold it up, and it won't reach the water. If you put in another, heavier object, one of just a certain weight, it will pass through the oil, which is too weak to stop it, and it will sink until it meets the water, which has the strength to hold it up. So in a liquid made of two liquids that don't mix, two bodies of unequal weight naturally settle in two different places, and the one will never rise or the other sink. Add other liquids that stay separate, and dip other bodies into them, and the same thing will happen.

"Picture the celestial matter that fills this great vortex as having different layers, wrapped around one another, with different weights, like oil and water and other liquids. The planets also have different weights. So each of them stops in the layer that has just the strength needed to hold it up, the layer that balances it, and you can see that it can never get out of it."

"I understand," said the Marquise, "that those weights sort out the ranks very well. If only there were something like that to sort them out among us, and keep people in the places that naturally suit them! Now I'm quite at ease about Jupiter. I'm glad he'll leave us in our little vortex with our single Moon. I'm easily satisfied, and I don't envy him the four he has."

"You'd be wrong to envy them," I said. "He has no more than he needs. He's five times farther from the Sun than we are, which means he's a hundred and sixty-five million leagues away, and so his moons receive, and send back to him, only fairly weak light. Their numbers make up for how little each one does. Otherwise, since Jupiter turns on itself in ten hours and its nights, which last only five, are very short, four moons wouldn't seem so necessary. The one nearest Jupiter makes its circle around him in forty-two hours, the second in three and a half days, the third in seven, the fourth in seventeen. And precisely because their courses are unequal, they combine to give him the prettiest spectacles in the world. Sometimes all four rise together and then almost instantly separate. Sometimes they're all at their noon, lined up one above another. Sometimes you see all four in the sky at equal distances. Sometimes, when two rise, two others set. Above all, I'd love to watch the endless game of eclipses they play, because no day goes by without their eclipsing one another or eclipsing the Sun. And since eclipses have become so familiar in that world, surely they're a source of entertainment there, not of terror as they are in this one."

"And of course you won't fail to have people living on these four moons," said the Marquise, "even though they're only small, subordinate planets, meant just to light another one during its nights?"

"Don't doubt it for a moment," I answered. "These planets are no less worthy of being inhabited for having the misfortune of being bound to circle a more important one."

"Then I'd like the inhabitants of Jupiter's four moons," she went on, "to be like colonies of Jupiter. If possible, they'd have received their laws and customs from him, and so they'd pay him some sort of homage and look on the great planet only with respect."

"Shouldn't the other moons also send deputies to Jupiter from time to time," I asked her, "to swear an oath of loyalty? For my part, I confess that the little superiority we have over the people of our own Moon makes me doubt that Jupiter has much over the inhabitants of his. I think the advantage he can most reasonably claim is that of frightening them. For example, in the moon nearest him, they see him sixteen hundred times bigger than our Moon looks to us. What a monstrous planet hanging over their heads! Truly, if the ancient Gauls were afraid the sky would fall on them and crush them, the inhabitants of that moon would have far more reason to fear a fall of Jupiter."

"Maybe that's the fear they have," she said, "in place of the fear of eclipses, which you assured me they're free of, and which they must replace with some other silliness."

"They absolutely must," I answered. "The inventor of the third system I told you about the other day, the famous Tycho Brahe, one of the greatest astronomers who ever lived, was in no danger of fearing eclipses the way the common people fear them. He spent his life with them. But would you believe what he feared in their place? If on leaving his house the first person he met was an old woman, or if a hare crossed his path, Tycho Brahe believed the day would be unlucky, and he hurried back to shut himself up at home, not daring to start the slightest thing."

"It wouldn't be fair," she replied, "since that man couldn't get free of the fear of eclipses without paying for it, for the people of that moon of Jupiter we were talking about to get off any cheaper. We won't give them any quarter. They'll obey the common law, and if they're free of one error they'll fall into another. But since I don't pride myself on being able to guess which, clear up another difficulty for me, please, one that's been on my mind for a few moments. If the Earth is so small compared with Jupiter, does Jupiter see us? I'm afraid we're unknown to him."

"In good faith, I think that's how it is," I said. "He'd have to see the Earth a hundred times smaller than we see him. That's too little. He doesn't see it at all. Here's the best that we can believe on our behalf. There will be astronomers on Jupiter who, after taking great pains to make excellent telescopes, and choosing the finest nights for observing, will finally have discovered in the heavens a very small planet they'd never seen before. At first the Journal des Savants of that country reports it. The people of Jupiter either never hear of it or just laugh at it. The philosophers, whose opinions it overturns, resolve not to believe a word of it. Only very reasonable people are willing even to doubt. They observe again, they see the little planet again, they make sure it isn't an illusion, they even begin to suspect it moves around the Sun, and after a thousand observations they find that this movement takes a year. And finally, thanks to all the pains the scholars have taken, it's known on Jupiter that our Earth exists in the world. The curious go and look at it at the end of a telescope, and even then the eye can barely catch it."

"If it weren't that it's not very pleasant to know we can only be found from Jupiter with telescopes," said the Marquise, "I'd enjoy picturing those Jovian telescopes aimed at us, as ours are aimed at him, and this mutual curiosity with which the planets look each other over and ask one another: 'What world is that? What people live there?'"

"It doesn't go as fast as you think," I answered. "Even if our Earth were seen from Jupiter, even if it were known there, our Earth isn't us. No one has the slightest suspicion that it could be inhabited. If someone happens to imagine it, God knows how all of Jupiter laughs at him. Maybe we're even the reason philosophers were put on trial there for trying to maintain that we exist.

"Still, I'd more readily believe that the people of Jupiter are busy enough making discoveries on their own planet that they don't think about us at all. It's so huge that if they sail, their Christopher Columbuses surely have plenty to do. The peoples of that world must not know even by reputation a hundredth of the other peoples, whereas on Mercury, which is very small, they're all neighbors, they live together familiarly, and going around their whole world counts as just a stroll.

"If we aren't seen from Jupiter, you can imagine that Venus is seen there even less, since it's farther from him, and Mercury least of all, being both smaller and farther. In compensation, Jupiter's inhabitants see their four moons, and Saturn with its moons, and Mars. That's enough planets to keep their astronomers busy. Nature was kind enough to hide from them the rest of what's in the universe."

"What?" said the Marquise. "You count that as a kindness?"

"Of course," I answered. "In this whole great vortex there are sixteen planets. Nature, wanting to spare us the trouble of studying all their motions, shows us only seven. Isn't that a big enough favor? But we, who don't feel its value, work so hard that we catch the other nine that had been hidden. And we're punished for it by the great labors astronomy now demands."

"I see," she said, "from that number of sixteen planets, that Saturn must have five moons."

"He does," I replied, "and with all the more reason because, since he goes around the Sun in thirty years, he has regions where the night lasts fifteen years, for the same reason that on the Earth, which turns in a year, there are nights of six months under the poles. But Saturn is twice as far from the Sun as Jupiter, and therefore ten times as far as we are. Would his five moons, so faintly lit, give him enough light during his nights? No. He has another resource, one that's singular and unique in the whole known universe. It's a great circle, a broad ring that surrounds him. It's raised high enough to be almost entirely out of the shadow of the planet's body, and so it reflects the Sun's light onto places that can't see the Sun. It reflects it from closer, and more strongly, than all five moons, because it's lower than the lowest of them."

"Truly," said the Marquise, with the look of a person coming back to herself in amazement, "all this is very well ordered. It's clear that nature had the needs of certain living beings in view, and that the distribution of moons wasn't left to chance. They've fallen only to the planets far from the Sun: the Earth, Jupiter, Saturn. It wouldn't have been worth giving any to Venus and Mercury, which receive only too much light, whose nights are very short, and which no doubt count them as greater gifts of nature than their very days. But wait. It seems to me that Mars, which is even farther from the Sun than the Earth, has no Moon."

"I can't hide it from you," I said. "It has none, and it must have resources for its nights that we don't know about. You've seen phosphors, those liquid or dry materials which soak up the Sun's light and are filled with it, and then give off quite a bright glow in the dark. Perhaps Mars has great, very tall rocks that are natural phosphors, and take in a supply of light during the day that they give back at night. You can't deny it would be a pleasant sight to see all those rocks light up on every side as soon as the Sun had set, making magnificent illuminations without any artifice, and with no heat to trouble anyone. You also know that in America there are birds so luminous in the dark that people can read by them. For all we know, Mars has great numbers of such birds, which, as soon as night falls, scatter in every direction and spread a new daylight."

"I'm satisfied with neither your rocks nor your birds," she said. "It would be pretty, all the same. But since nature gave so many moons to Saturn and Jupiter, that's a sign moons are needed. I'd have been glad if all the worlds far from the Sun had them, if Mars hadn't come along and made an unpleasant exception."

"Ah, truly," I replied, "if you dabbled in philosophy more than you do, you'd have to get used to seeing exceptions in the best systems. There's always something that fits exactly right, and then something else that's made to fit as best it can, or that's left aside if you despair of managing it. Let's do the same with Mars, since it doesn't favor us, and not speak of it.

"We'd be quite astonished, if we were on Saturn, to see over our heads at night that great ring, stretching like a semicircle from one end of the horizon to the other, and sending the Sun's light back down to us, acting like a moon that never leaves."

"And won't we put inhabitants on that great ring?" she interrupted, laughing.

"Though I'm inclined," I answered, "to send people just about everywhere, quite boldly, I admit I wouldn't dare put any there. That ring strikes me as too irregular a home. As for the five little moons, we can't get out of populating them. If, however, the ring were only, as some suspect, a circle of moons that follow each other very closely and move at an equal speed, and the five little moons were five that had escaped from that great circle, what a number of worlds there would be in the vortex of Saturn! However that may be, the people of Saturn are pretty miserable, even with the ring's help. It gives them light, but what light, at that distance from the Sun! The Sun itself, which they see a hundred times smaller than we see it, is for them just a small, white, pale star, with only a feeble brightness and warmth. And if you put them in our coldest countries, in Greenland or Lapland, you'd see them sweat in big drops and die of the heat. If they had water, it wouldn't be water for them but polished stone, marble. And spirits of wine, which never freezes here, would be hard as our diamonds."

"You give me an idea of Saturn that freezes me," said the Marquise, "whereas a little while ago you were heating me up by talking about Mercury."

"Naturally," I answered, "the two worlds at the ends of this great vortex are opposites in everything."

"So people must be very wise on Saturn," she went on, "since you told me everyone was mad on Mercury."

"If they aren't very wise on Saturn," I replied, "they're at least, by all appearances, very phlegmatic. They're people who don't know what laughing is, who always take a day to answer the smallest question they're asked, and who would have found Cato of Utica too playful and frivolous."

"A thought occurs to me," she said. "All the inhabitants of Mercury are lively, all those of Saturn are slow. Among us some are lively and others slow. Could that be because our Earth sits right in the middle of the other worlds, so we share in the extremes? For human beings there's no fixed, settled character. Some are made like the people of Mercury, others like those of Saturn, and we're a mixture of all the kinds found on the other planets."

"I rather like that idea," I said. "We make up such a strange assembly that you could believe we'd been collected from several different worlds. By that reckoning it's quite convenient to be here: you see all the other worlds in miniature."

"At least," said the Marquise, "one very real convenience that our world has from its situation is that it's neither as hot as Mercury or Venus nor as cold as Jupiter or Saturn. What's more, we happen to be in a part of the Earth where we feel neither too much heat nor too much cold. Truly, if a certain philosopher thanked nature for making him a man and not a beast, a Greek and not a barbarian, I want to thank it for putting me on the most temperate planet in the universe, and in one of the most temperate places on that planet."

"If you take my advice, Madame," I answered, "you'll thank it for making you young and not old; young and beautiful, and not young and plain; a young and beautiful Frenchwoman, and not a young and beautiful Italian. Those are far more reasons for gratitude than the ones you draw from the position of your vortex, or the climate of your country."

"Good heavens!" she replied. "Let me be grateful for everything, even for the vortex I'm placed in. The measure of happiness we've been given is small enough. None of it should be wasted, and it's good to have a taste for the most common and least considerable things, one that puts them to use. If we wanted only sharp pleasures, we'd have few of them, we'd wait a long time for them, and we'd pay dearly."

"So you promise me," I said, "that if such sharp pleasures were offered to you, you'd remember the vortices, and me, and wouldn't neglect us altogether?"

"Yes," she answered, "but see that philosophy keeps supplying me with new pleasures."

"For tomorrow, at least," I said, "I hope they won't fail you. I have fixed stars, which surpass everything you've seen so far."

The Fifth Evening: The Fixed Stars Are Suns, Each Lighting a World

The Marquise was truly impatient to learn what would become of the fixed stars. "Will they be inhabited like the planets?" she asked me. "Won't they? What are we going to do with them?"

"You might guess it yourself, if you really wanted to," I said. "The fixed stars can't be any closer to the Earth than 27,660 times the distance from here to the Sun, which is thirty-three million leagues, and if you annoyed an astronomer, he would put them even farther. The distance from the Sun to Saturn, the farthest planet, is only three hundred thirty million leagues. That's nothing next to the distance from the Sun, or the Earth, to the fixed stars. Nobody bothers to count it. Their light, as you can see, is quite bright and brilliant. If they received it from the Sun, it would have to be very faint by the end of such a dreadful journey. And then, by a reflection that would weaken it even more, they would have to send it back to us across that same distance. It would be impossible for light that had gone through a reflection and made the same journey twice to have the strength and brilliance of the light of the fixed stars. So they shine by their own light. In a word, every one of them is a Sun."

"Am I wrong," cried the Marquise, "or do I see where you're leading me? Are you going to say: the fixed stars are so many Suns; our Sun is the center of a vortex that turns around it; so why shouldn't each fixed star also be the center of a vortex that turns around it? Our Sun has planets that it lights, so why shouldn't each fixed star have planets that it lights too?"

"All I can answer," I said, "is what Phaedra answered Oenone: 'You are the one who named him.'"

"But," she went on, "the universe has become so big that I'm lost in it. I don't know where I am anymore. I'm nothing. What, everything is divided into vortices, tossed in a jumble among one another? Every star is the center of a vortex, perhaps as large as the one we live in? All this immense space, which holds our Sun and our planets, is only a tiny scrap of the universe? As many spaces like it as there are fixed stars? It bewilders me, it upsets me, it terrifies me."

"And it puts me at ease," I answered. "When the sky was just that blue dome with the stars nailed to it, the universe seemed small and cramped to me, and I felt almost squeezed. Now that we've given that dome infinitely more breadth and depth by dividing it into thousands upon thousands of vortices, I feel as if I can breathe more freely, as if I'm standing in bigger air, and the universe certainly has a whole different grandeur. Nature spared nothing in making it. She lavished riches on it, in a way entirely worthy of her. Nothing is so beautiful to picture as this staggering number of vortices, each with a Sun at its middle, making planets turn around it. The inhabitants of a planet in one of these endless vortices see the Suns of the surrounding vortices on every side. But they can't possibly see those worlds' planets, which have only a weak light borrowed from their Sun and don't send it beyond their own world."

"You're offering me," she said, "a kind of view so long that the eye can't reach the end of it. I see the people of the Earth clearly. Then you show me those of the Moon and the other planets of our vortex, quite clearly, really, though less clearly than those of the Earth. After them come the inhabitants of the planets of the other vortices. I admit they're far back in the distance, and however hard I try to see them, I can hardly make them out at all. In fact, aren't they almost wiped out by the very phrase you have to use when you talk about them? You have to call them the inhabitants of one of the planets of one of those vortices, of which there are infinitely many. And the same phrase fits us! Admit it, you can hardly pick us out anymore among so many worlds. As for me, I'm beginning to see the Earth as so frightfully small that I don't think I'll be eager about anything from now on. Surely, when people are so hungry to get ahead, when they make plan after plan and take such trouble, it's because they don't know about the vortices. I fully intend to let my laziness profit from my new lights, and when people reproach me for being idle, I'll say: 'Ah, if you only knew what the fixed stars are!'"

"Alexander must not have known," I replied. "A certain author who holds that the Moon is inhabited says, in all seriousness, that Aristotle couldn't possibly have failed to hold such a reasonable opinion (how could a truth have escaped Aristotle?), but that he never wanted to say anything about it, for fear of upsetting Alexander, who would have been in despair at seeing a world he couldn't conquer. All the more reason they would have kept the vortices of the fixed stars a secret from him, if anyone had known about them back then. Mentioning them would have been a terrible way to court his favor. As for me, I do know about them, and I'm very sorry I can't get any use out of what I know. By your reasoning, at most they cure ambition and restlessness, and I don't suffer from those diseases. A little weakness for whatever is beautiful, that's my affliction, and I don't think the vortices can do anything about it. Other worlds make this one seem small to you, but they don't spoil beautiful eyes or a beautiful mouth. Those are still worth what they're worth, in spite of every possible world."

"Love is a strange thing," she answered, laughing. "It gets out of everything, and no system can do it any harm. But now tell me frankly, is your system really true? Don't hide anything from me, I'll keep it secret. It seems to me it rests on nothing but a small, very flimsy point of fitness. A fixed star shines by its own light like the Sun, so it must be, like the Sun, the center and soul of a world, with planets turning around it. Is that really absolutely necessary?"

"Listen, Madame," I said, "since we're in the mood to keep mixing foolish gallantry into our most serious talk, mathematical reasoning works just like love. You can't grant a lover the smallest favor without soon having to grant him a bigger one, and in the end it goes a long way. In the same way, grant a mathematician the slightest principle, and he'll draw a consequence out of it that you'll have to grant him too, and from that consequence another. In spite of yourself, he leads you so far that you can hardly believe it. Both kinds of people always take more than they're given. You agree that when two things are alike in everything I can see, I can believe them alike in what I can't see, as long as nothing else stands in the way. From that I concluded that the Moon is inhabited, because it resembles the Earth, and the other planets are, because they resemble the Moon. I find that the fixed stars resemble our Sun, so I give them everything it has. You're in too deep to turn back. You have to take the step gracefully."

"But," she said, "on the strength of this resemblance you set up between the fixed stars and our Sun, the people of another great vortex must see our Sun as just a small fixed star, one that shows itself to them only during their nights."

"There's no doubt of it," I replied. "Our Sun is so close to us, compared with the Suns of the other vortices, that its light must have infinitely more force on our eyes than theirs does. So when we see it, we see only it, and it wipes out everything else. But in another great vortex, a different Sun rules, and it in turn wipes out ours, which shows up there only at night, along with the rest of the foreign Suns, that is, the fixed stars. They fasten it to that great dome of the sky along with the others, and it makes up part of some Bear or some Bull. As for the planets that turn around it, our Earth for example, since no one can see them from so far away, no one even thinks of them. So every Sun is a daytime Sun for the vortex where it stands, and a nighttime Sun for all the other vortices. In its own world it's one of a kind. Everywhere else it just helps make up the numbers."

"But surely," she went on, "in spite of this equality, the worlds must differ in a thousand ways. A common ground of resemblance still leaves room for endless differences."

"Certainly," I said, "but the trouble is guessing them. What do I know? One vortex has more planets turning around its Sun, another has fewer. In one there are lesser planets that turn around bigger ones; in another there are none. Here they're all bunched up around their Sun in a little ball, beyond which a great empty space stretches out to the neighboring vortices. Elsewhere they run their course out near the edges of the vortex and leave the middle empty. I don't doubt that there might even be some deserted vortices with no planets at all. Others might have a Sun that isn't at the center, so it really moves and carries its planets along with it. Others might have planets that rise or sink relative to their Sun as the balance that holds them suspended shifts. Well, what more do you want? That's plenty for a man who has never left his own vortex."

"It's hardly plenty," she answered, "for the number of worlds. What you're describing would only do for five or six, and from here I can see thousands."

"What would you say, then," I went on, "if I told you that there are many more fixed stars than the ones you see, that with telescopes you discover an infinite number that don't show themselves to the eye, and that in a single constellation where people counted perhaps twelve or fifteen, there are as many as were once seen in the whole sky?"

"Mercy!" she cried. "I give up. You're overwhelming me with worlds and vortices."

"I know what I'm saving for you," I added. "You see that whiteness called the Milky Way. Can you imagine what it is? An infinity of little stars, invisible to the eye because they're so small and scattered so close together that they seem to form one continuous glow. I wish you could see through a telescope this anthill of stars, this seedbed of worlds. In a way they're like the Maldive Islands, those twelve thousand little islands or sandbanks, separated only by channels of sea that you could almost jump across like ditches. In the same way, the little vortices of the Milky Way are so tightly packed that it seems to me people in one world could talk to those in the next, or even shake hands. At least I believe the birds of one world pass easily into another, and that pigeons could be trained there to carry letters, the way they carry them here in the Levant from one city to another. These little worlds evidently escape the general rule by which a Sun in its own vortex wipes out all the foreign Suns the moment it appears. If you're in one of the little vortices of the Milky Way, your Sun is hardly any closer to you, and has no noticeably greater force on your eyes, than a hundred thousand other Suns of the neighboring little vortices. So you see your sky sparkling with an infinite number of fires that are very close to one another and not far from you. When you lose sight of your own particular Sun, you still have plenty left, and your night is no less bright than your day. At least the difference can't be noticeable. To put it more precisely, you never have night at all. The people of those worlds, used to a constant brightness as they are, would be very astonished if you told them there are unfortunate creatures who have real nights, who fall into deep darkness, and who, when they do have light, see only a single Sun. They'd look on us as beings nature had treated shabbily, and our condition would make them shudder with horror."

"I won't ask you," said the Marquise, "whether there are Moons in the worlds of the Milky Way. I can see they'd be no use to the main planets there, which have no night, and which besides move in spaces too narrow to bother with that baggage of lesser planets. But do you know that by multiplying worlds so generously for me, you've raised a real difficulty? The vortices whose Suns we see touch the vortex we're in. Vortices are round, aren't they? And how can so many balls touch a single one? I try to picture it, and I feel I can't."

"It shows a great deal of wit," I answered, "to have that difficulty, and even to be unable to solve it. It's a very good difficulty in itself, and the way you conceive it, it has no answer, and it takes very little wit to find answers to what has none. If our vortex were shaped like a die, it would have six flat faces and be far from round, but on each of those faces you could set a vortex of the same shape.

"If instead of six flat faces it had twenty, fifty, a thousand, then as many as a thousand vortices could rest on it, one on each face. And you understand that the more flat faces a body has bounding it on the outside, the closer it comes to being round. So a diamond cut with facets on every side, if the facets were very small, would be nearly as round as a pearl of the same size. Vortices are round only in that way. They have an infinity of faces on the outside, each of which carries another vortex. These faces are very unequal. Here they're bigger, there smaller. The smallest ones of our vortex, for example, correspond to the Milky Way and support all those little worlds. Suppose two vortices resting on two neighboring faces leave some gap between them underneath, as must happen very often. Immediately nature, who is careful with her ground, fills the gap with a small vortex or two, or perhaps a thousand, which don't get in the others' way and still amount to one, or two, or a thousand worlds more. So we can see many more worlds than our vortex has faces to carry them. I'd bet that although these little worlds were made only to be thrown into corners of the universe that would otherwise have gone to waste, and although they're unknown to the worlds that touch them, they're still very pleased with themselves. These are surely the ones whose little suns can be discovered only with telescopes, and they exist in a truly staggering quantity. In the end, all these vortices fit together with one another as well as they can. Since each one has to turn around its Sun without changing place, each takes on whatever way of turning is most convenient and easy in its situation. They mesh with one another, in a way, like the wheels of a watch, and help one another's motion. It's true, though, that they also work against one another. Each world, they say, is like a balloon that would expand if it were left alone, but it's immediately pushed back by the neighboring worlds and shrinks into itself, after which it starts to swell again, and so on. And some philosophers claim that the fixed stars send us that trembling light, and seem to shine in fits and starts, only because their vortices are constantly pushing on ours and constantly being pushed back."

"I like all these ideas very much," said the Marquise. "I like these balloons that swell and shrink every moment, and these worlds that are always fighting, and above all I like seeing how this fight creates a traffic in light between them, which is apparently the only traffic they can have."

"No, no," I said, "it's not the only one. The neighboring worlds sometimes send us visitors, and quite magnificently too. We get comets from them, which are adorned with a dazzling head of hair, or a venerable beard, or a majestic tail."

"Ah, what deputies!" she said, laughing. "We could easily do without their visit. All it does is frighten people."

"They frighten only children," I replied, "because of their extraordinary outfits. But children are many. Comets are just planets that belong to a neighboring vortex. They were moving near its edges. But that vortex, perhaps pressed differently by the ones around it, is rounder on top and flatter underneath, and it's the underside that faces us. These planets, which began to move in a circle up near the top, didn't foresee that down below the vortex would fail them, because it's as if squashed there. To keep up their circular motion, they have to enter another vortex, which I suppose is ours, and cut across its outer edges. That's why they always stay very high above us. We can suppose they travel beyond Saturn. Given the prodigious distance of the fixed stars, there has to be a great empty space without planets between Saturn and the edges of our vortex. Our enemies reproach us for the uselessness of this great space. They can stop worrying. We've found its use. It's the guest quarters for the foreign planets that enter our world."

"I see," she said. "We don't allow them to come into the heart of our vortex and mix with our planets. We receive them the way the Grand Sultan receives the ambassadors sent to him. He doesn't do them the honor of lodging them in Constantinople, only in a suburb of the city."

"We have another thing in common with the Ottomans," I went on. "They receive ambassadors without sending any back, and we don't send any of our planets to the neighboring worlds."

"Judging by all this," she replied, "we're quite proud. Still, I'm not sure yet what to make of it. These foreign planets look very threatening with their tails and beards, and perhaps they're sent to insult us. Ours, which aren't built the same way, wouldn't be so good at making themselves feared if they went to the other worlds."

"The tails and beards," I answered, "are pure appearance. The foreign planets don't differ at all from ours. But when they enter our vortex they take on the tail or the beard through a certain kind of illumination they receive from the Sun, which hasn't yet been very well explained among us. Still, we're sure it's only a kind of illumination. We'll figure it out when we can."

"Then I'd like our Saturn," she said, "to go pick up a tail or a beard in some other vortex and spread terror there, and afterward, having taken off that terrible getup, come back and settle in here with the other planets to its ordinary duties."

"It's better for Saturn," I answered, "not to leave our vortex. I told you about the shock that happens where two vortices push and push back against each other. I believe a poor planet is tossed around quite roughly as it crosses, and its inhabitants are none the better for it. We think we're very unlucky when a comet appears to us. It's the comet itself that's unlucky."

"I don't believe it," said the Marquise. "It brings us all its inhabitants in good health. Nothing is so entertaining as changing vortices like that. We who never leave our own lead a rather boring life. If the inhabitants of a comet have wit enough to foresee when they'll pass into our world, the ones who have already made the trip tell the others in advance what they'll see. 'You'll soon discover a planet with a great ring around it,' they may say, speaking of Saturn. 'You'll see another with four little ones following it.' Maybe there are even people whose job is to watch for the moment they enter our world, and who cry out at once, 'New Sun! New Sun!' like those sailors who cry, 'Land! Land!'"

"So there's no use trying to make you pity the inhabitants of a comet," I said. "But I hope at least you'll feel sorry for those who live in a vortex whose Sun goes out and who remain in eternal night."

"What?" she cried. "Suns go out?"

"Yes, of course," I answered. "The Ancients saw fixed stars in the sky that we don't see there anymore. Those Suns lost their light. Great desolation, surely, throughout the whole vortex, a general dying-off on all the planets. For what can you do without a Sun?"

"That's too gloomy an idea," she said. "Isn't there some way to spare me it?"

"I can tell you, if you like," I answered, "what some very capable people say: that the fixed stars that have disappeared are not extinguished for that reason, that they are Suns that are only half so, that is, with one dark half and one bright half. As they rotate on themselves, they show us now the bright half and now the dark half, and then we no longer see them. By all appearances, the fifth Moon of Saturn is made that way. For during part of its revolution, it's lost from sight completely, and that isn't because it's farther from the Earth then. On the contrary, it's sometimes closer than at other times, when it lets itself be seen. And although that Moon is a planet, which naturally doesn't prove anything for a Sun, we can easily imagine a Sun partly covered with permanent spots, whereas ours has only passing ones. I'd gladly adopt that opinion to oblige you, since it's gentler than the other. But I can adopt it only for certain stars that have regular times for appearing and disappearing, as people have begun to notice. Otherwise half-Suns can't exist. But what shall we say of the stars that disappear and don't show themselves again after the time in which they should surely have finished turning on themselves? You're too fair-minded to want me to make you believe those are half-Suns. Still, I'll make one more effort in your favor. These Suns haven't gone out. They've only sunk into the immense depth of the heavens, and we can no longer see them. In that case the vortex has followed its Sun, and everything there is going well. It's true that most of the fixed stars don't have this motion that takes them away from us. At other times they'd have to come closer again, and we'd see them now bigger and now smaller, which doesn't happen. But we'll suppose that only a few small vortices, lighter and more agile, slip between the others and make certain loops at the end of which they come back, while the bulk of the vortices stays motionless. But here comes a strange misfortune. There are fixed stars that show themselves to us, spend a long time doing nothing but appearing and disappearing, and finally vanish altogether. Half-Suns would reappear at regular times. Suns that sank into the sky would vanish only once, not to reappear for a long time. Make up your mind, Madame, and be brave. These stars must be Suns that darken enough to stop being visible to our eyes, then light up again, and in the end go out altogether."

"How can a Sun darken and go out," said the Marquise, "when it's in itself a source of light?"

"Very easily, according to Descartes," I answered. "He supposes that the spots on our Sun are scum or mist, which can thicken, several of them gathering together and hooking onto one another. Then they'll go on to form a crust around the Sun that keeps growing, and farewell, Sun. And if the Sun is a fire attached to a solid matter that feeds it, we're no better off, because the solid matter will be used up. They say we've already had a narrow escape. The Sun was very pale for whole years, for example the year that followed the death of Caesar. That was the crust starting to form. The Sun's strength broke it up and dispersed it, but if it had kept on, we'd have been lost."

"You make me tremble," said the Marquise. "Now that I know what the consequences of the Sun's paleness are, I think that instead of going to my mirror every morning to see whether I'm pale, I'll go look at the sky to see whether the Sun is."

"Ah, Madame," I replied, "be reassured. It takes time to ruin a world."

"But in the end," she said, "it takes only time?"

"I admit it," I replied. "This whole immense mass of matter that makes up the universe is in perpetual motion, and no part of it is entirely exempt. As soon as there's motion anywhere, don't trust it. Changes have to come, slow or sudden, but always in times proportioned to the effect. The Ancients were amusing to imagine that the heavenly bodies were of a nature never to change, just because they hadn't yet seen them change. Had they had the time to make sure by experience? The Ancients were young next to us. If roses, which last only a day, wrote histories and left memoirs to one another, the first roses would have painted a certain portrait of their gardener, and over more than fifteen thousand ages of roses, the ones who passed it on to those who were to follow would have changed nothing in it. On that basis they'd say: 'We've always seen the same gardener. As far back as any rose remembers, no one has seen anyone but him. He has always looked just as he does. Surely he doesn't die like us. He doesn't even change.' Would the roses' reasoning be sound? Yet it would have more foundation than what the Ancients reasoned about the heavenly bodies. And even if no change had happened in the heavens up to today, even if they seemed to show that they were made to last forever without any alteration, I still wouldn't believe it. I'd wait for a longer experience. Should we set our own lifespan, which lasts only an instant, as the measure of anyone else's? Does it follow that what has lasted a hundred thousand times longer than we have must last forever? It isn't so easy to be eternal. A thing would have to have lived through many human lifetimes laid end to end before it began to give any sign of immortality."

"Truly," said the Marquise, "I see the worlds are far from being able to claim it. I wouldn't even do them the honor of comparing them to that gardener who lasts so long next to the roses. They're only like the roses themselves, which are born and die in a garden one after another. For I expect that if old stars disappear, new ones appear. The species has to renew itself."

"There's no fear that it will perish," I answered. "Some will tell you these are only Suns that are drawing closer to us after being lost to us for a long time in the depths of the sky. Others will tell you they're Suns that have broken free of the dark crust that was beginning to surround them. I readily believe all that may be so. But I also believe the universe may have been made so that new Suns form from time to time. Why couldn't the matter suited to making a Sun, after being scattered in many different places, gather together in the long run in one particular spot and lay the foundations of a new world there? I'm all the more inclined to believe in these new productions because they fit better with the high idea I have of nature's works. Would she have the power only to bring plants or animals to birth and death in a continual round? I'm convinced, and you already are too, that she uses this same power on worlds, and that it costs her no more. But we have more than mere conjecture on this. The fact is that for nearly a hundred years now, since we've been seeing with telescopes a sky that is entirely new and was unknown to the Ancients, there are not many constellations where some noticeable change hasn't happened. And it's in the Milky Way that people notice the most, as if in that anthill of little worlds there were more motion and restlessness."

"Honestly," said the Marquise, "I find the worlds, the heavens and the heavenly bodies so subject to change now that I'm completely over it."

"Let's get over it even better, if you take my advice," I replied. "Let's not speak of it anymore. Besides, you've now arrived at the last dome of the heavens, and to tell you whether there are still stars beyond, one would have to be cleverer than I am. Put worlds there, or don't. It's up to you. Those great invisible countries are properly the empire of philosophers, who can make them be or not be as they wish, or be whatever they wish. It's enough for me to have led your mind as far as your eyes can go."

"What!" she cried. "I have the whole system of the universe in my head! I'm learned!"

"Yes," I replied, "you're reasonably so, and you have the convenience of being able to disbelieve everything I've told you the moment you feel like it. I ask only one reward for my trouble: that you never see the Sun, or the sky, or the stars, without thinking of me."

Since I have given the public an account of these Conversations, I think I should keep nothing back from it on this subject. I will publish one more Conversation, which took place long after the others but was exactly of the same kind. It will be called an Evening, since the others were, because it's better for everything to go under the same title.

The Sixth Evening: New Thoughts, and the Latest Discoveries in the Sky

It had been a long time since the Marquise and I had talked about the worlds. We had even started to forget that we ever had. Then one day I went to call on her, and arrived just as two gentlemen, clever men and fairly well known in society, were leaving.

"You can see what kind of visit I've just had," she said as soon as she saw me. "I'll admit it's left me suspecting that you may have spoiled my mind."

"I'd be very proud," I answered, "to have had that much power over you. I can't imagine anything harder to bring off."

"I'm afraid you've managed it all the same," she said. "I don't know how the conversation turned to the worlds with those two men who just left. Maybe they steered it there on purpose, out of mischief. Anyway, I lost no time in telling them that all the planets are inhabited. One of them said he was quite sure I didn't believe it. I told him, with all the sincerity in the world, that I did. He kept taking it for a pretense, the joke of a woman who wanted to amuse herself. I decided the reason he was so stubborn about not believing me, even about my own opinions, was that he thought too well of me to imagine I could hold such an extravagant idea. The other one doesn't think so highly of me, so he took me at my word. Why did you get me hooked on something that the people who respect me can't believe I'd say seriously?"

"But Madame," I replied, "why did you say it seriously to people who I'm sure weren't capable of following any argument that was the least bit serious? Is that any way to expose the inhabitants of the planets? Let's be content to be a small, select company of believers, and not spread our mysteries among the common crowd."

"What!" she cried. "You call the two men who just left here the common crowd?"

"They're very clever," I said, "but they never reason. Reasoners are hard people, and they'll call those two the crowd without a second thought. And the other side takes its revenge by making the reasoners look ridiculous. It seems to me a very well-established arrangement that each kind of person despises whatever it lacks. If it were possible, we ought to adapt ourselves to each. It would have been far better to joke about the inhabitants of the planets with those two men, since they know how to joke, than to reason about them, since they don't know how. You'd have left with their good opinion, and the planets wouldn't have lost a single inhabitant."

"Betraying the truth!" said the Marquise. "You have no conscience."

"I confess," I said, "that I don't have great zeal for truths of that kind, and I gladly sacrifice them to the smallest conveniences of social life. I can see, for example, what it is that stops the opinion about inhabited planets from passing for as likely as it is, and what always will. The planets present themselves to our eyes as bodies that give off light, not as broad fields or meadows. We could easily believe that fields and meadows were inhabited, but luminous bodies? No way. Reason can come and tell us as much as it likes that the planets have fields and meadows, but reason arrives too late. The first glance has already done its work on us, and we won't listen to reason anymore: the planets are just luminous bodies. And then, what would their inhabitants even look like? Our imagination would have to picture their shapes right away, and it can't, so the quickest thing is to believe they don't exist. Would you have me go to war against those formidable powers called the senses and the imagination, just to establish the inhabitants of the planets, whose interests concern me only from a fair distance? That would take a lot of courage. It isn't easy to persuade people to put their reason in place of their eyes. Sometimes I meet people sensible enough to believe, after a thousand proofs, that the planets are Earths. But they don't believe it the way they would if they had never seen the planets looking different. They keep remembering the first idea they formed, and they never quite get over it. Those are the people who, even while believing our opinion, seem to be doing it a favor, and only support it because of a certain pleasure they take in how unusual it is."

"Well, but," she interrupted, "isn't that enough for an opinion that's merely likely?"

"You'd be very surprised," I said, "if I told you that the word 'likely' is rather modest. Is it merely likely that Alexander existed? You feel quite sure of it. What is that certainty based on? On the fact that you have every proof you could want in a matter like this, and that no reason for doubt comes up that could hold your mind back and stop it. Otherwise, you've never seen Alexander, and you have no mathematical demonstration that he had to exist. But what would you say if the inhabitants of the planets were in roughly the same position? No one can show them to you, and you can't ask for a demonstration like a problem in mathematics. But you have every proof one could want for a thing like this: the complete resemblance of the planets to the Earth, which is inhabited; the impossibility of imagining any other purpose they could have been made for; the fertility and magnificence of nature; the consideration nature seems to have shown for the needs of their inhabitants, such as giving moons to the planets far from the Sun, and more moons to the farthest ones. And, most important of all, everything points one way and nothing at all points the other. You couldn't come up with the slightest ground for doubt unless you took back the eyes and the mind of the crowd. In short, suppose these inhabitants of the planets do exist. They couldn't announce themselves with more signs, or with clearer ones. After that, it's for you to decide whether you want to treat them as merely likely."

"But you wouldn't want it to seem as certain to me as it does that Alexander existed?" she said.

"Not quite," I answered. "Even though we have as much proof about the inhabitants of the planets as we can have in our position, there isn't a great quantity of it."

"I'm going to give up on the inhabitants of the planets," she interrupted, "because I no longer know what rank to give them in my mind. They aren't quite certain, and they're more than likely. It confuses me too much."

"Ah, Madame," I said, "don't be discouraged. The plainest, crudest clocks tell the hours. Only the ones built with more art tell the minutes. In the same way, ordinary minds feel the difference between simple likelihood and complete certainty. But only the finer minds feel the more and the less of certainty or likelihood, and mark off the minutes of it, so to speak, by their feeling. Put the inhabitants of the planets a little below Alexander, but above I don't know how many points of history that aren't fully proved, and I think they'll be well placed there."

"I like order," she said, "and you do me a favor by arranging my ideas. But why didn't you take that trouble already?"

"Because it doesn't do much harm," I answered, "if you believe in the inhabitants of the planets a little more or a little less than they deserve. I'm sure you don't believe in the motion of the Earth as much as you ought to. Is that a great loss to you?"

"Oh, as for that," she said, "I do my duty. You have nothing to reproach me with. I firmly believe the Earth turns."

"And yet I haven't told you the best reason that proves it," I said.

"Ah!" she cried. "So it was a betrayal, making me believe things on weak proofs. Did you not think me worthy of believing on good reasons?"

"I only proved things to you," I answered, "with gentle little arguments, suited to your use. Should I have used ones as solid and sturdy as if I'd had to take on a Doctor of the university?"

"Yes," she said. "Take me for a Doctor right now, and let's see this new proof of the Earth's motion."

"Gladly," I said, "here it is. I'm very fond of it, perhaps because I believe I found it myself. But it's so good and so natural that I wouldn't dare swear I'm its inventor. One thing is sure: a stubborn scholar who wanted to answer it would be reduced to talking at great length, which is the only way a scholar can ever be confounded. Either all the heavenly bodies turn around the Earth in twenty-four hours, or the Earth turns on itself in twenty-four hours and passes that motion on to all the heavenly bodies. But that they really make this twenty-four-hour revolution around the Earth is the least likely thing in the world, even though the absurdity doesn't leap to the eye at first. All the planets certainly make their great revolutions around the Sun. But these revolutions differ from one another according to the planets' distances from the Sun. The farthest ones take longer to make their circuit, which is only natural. The same order holds even among the small secondary planets that circle a large one. The four moons of Jupiter and the five of Saturn make their circles in more or less time around their great planet, depending on whether they're farther from it or nearer. Besides, it's certain that the planets also turn on their own centers, and these motions are unequal too. No one knows for sure what governs this inequality. It may be the planets' different sizes, or their different solidity, or the different speeds of the particular vortices that enclose them, and of the liquid matter that carries them along. But the inequality itself is quite certain. And in general, this is the order of nature: whatever several things have in common turns up at the same time varied by particular differences."

"I follow you," the Marquise interrupted, "and I think you're right. Yes, I agree with you. If the planets turned around the Earth, they'd turn in unequal times according to their distances, just as they do around the Sun. Isn't that what you mean?"

"Exactly, Madame," I said. "Their unequal distances from the Earth ought to produce differences in this supposed motion around the Earth. And the fixed stars, which are so prodigiously far from us, so far above anything that could take on a general motion around us, or at least placed where that motion ought to be very weak: wouldn't it be quite likely that they don't turn around us in twenty-four hours, the way the Moon does, which is so close? And the comets, which are strangers in our vortex and follow such different paths there: shouldn't they be excused from all turning around us in that same twenty-four hours? But no. Planets, fixed stars, comets, everything will turn around the Earth in twenty-four hours. Even so, if there were a few minutes of difference among these motions, we could live with it. But they'll all be of the most exact equality, or rather of the only exact equality in the world: not one minute more or less. Truly, that has to be strangely suspicious."

"Oh!" said the Marquise. "Since it's possible that this great equality exists only in our imagination, I feel quite sure it doesn't exist outside it. I'm glad that something that isn't in nature's character falls entirely on us, and that nature is let off, even if it's at our expense."

"For my part," I said, "I'm so much an enemy of perfect equality that I don't find it right that all the turns the Earth makes on itself each day should be precisely twenty-four hours and always equal to one another. I'd be rather inclined to believe there are differences."

"Differences!" she cried. "Don't our pendulum clocks show a perfect equality?"

"Oh," I answered, "I challenge the pendulum clocks. They can't be perfectly accurate themselves. And if one day they showed that one twenty-four-hour turn was longer or shorter than another, people would rather believe the clocks were out of order than suspect the Earth of any irregularity in its revolutions. A funny sort of respect they have for it! I wouldn't trust the Earth much more than a clock. Pretty much the same things that would throw one off would throw off the other. I only think the Earth takes longer than a clock to go noticeably wrong, and that's the only advantage we can grant it. Couldn't it be gradually drawing nearer to the Sun? And then, finding itself in a place where the matter was more agitated and the motion faster, it would complete its double revolution, around the Sun and around itself, in less time. The years would be shorter, and so would the days. We couldn't notice it, because we'd still divide the years into three hundred sixty-five days and the days into twenty-four hours. So, without living any longer than we do now, we'd live more years. And the opposite: if the Earth moved away from the Sun, we'd live fewer years than we do, and yet we wouldn't live any less."

"It seems quite likely," she said, "that even if that were so, long ages upon ages would produce only very small differences."

"I agree," I said. "Nature doesn't proceed abruptly. Her method is to bring everything about by degrees that are only noticeable in very sudden, very easy changes. We're hardly able to notice any but the change of the seasons. The others, which happen with a certain slowness, almost always escape us. And yet everything is in perpetual motion, and so everything changes. Even a certain young lady whom people saw in the Moon through telescopes, perhaps forty years ago, has aged considerably. She had a rather beautiful face. Her cheeks have sunk in, her nose has grown longer, her forehead and chin have jutted forward, so that all her charms are gone, and people even fear for her life."

"What are you telling me?" the Marquise interrupted.

"It's no joke," I said. "In the Moon you could make out a particular shape that looked like a woman's head emerging from among some rocks, and a change has happened in that spot. Some pieces of mountain have fallen, and they've left three peaks exposed, which now can only serve to make up the forehead, nose and chin of an old woman."

"Doesn't it seem," she said, "as if some spiteful fate has a special grudge against beauty? It went after exactly this young lady, out of the whole Moon."

"Perhaps, to make up for it," I replied, "the changes that happen on our Earth improve some face that the people of the Moon see there. I mean some face in the Moon's own manner, because everyone projects onto objects the ideas they're full of. Our astronomers see the faces of young ladies on the Moon. It might be that women who observed it would see handsome men's faces there. As for me, Madame, I wonder whether I wouldn't see you there."

"I admit," she said, "that I couldn't help feeling obliged to anyone who found me there. But I'm going back to what you were saying a moment ago. Do considerable changes happen on the Earth?"

"It seems very likely," I answered, "that they have. Many mountains, high up and far from the sea, have great beds of seashells, which necessarily show that water once covered them. Often, still quite far from the sea, you find stones with petrified fish in them. Who could have put them there, if the sea hadn't been there? The fables say that Hercules separated two mountains with his own two hands, Calpe and Abyla, which stood between Africa and Spain and held back the ocean. The sea then rushed violently in over the land and made the great gulf we call the Mediterranean. Fables aren't entirely fables. They're histories of distant times that have been distorted, either by the ignorance of peoples or by their love of the marvelous, both very ancient diseases of mankind. That Hercules split two mountains with his hands isn't very believable. But that in the time of some Hercules (for there were fifty of them) the Ocean broke through two mountains weaker than the rest, perhaps with the help of an earthquake, and threw itself in between Europe and Africa, I could believe without much difficulty. That was a fine spot the people of the Moon then saw suddenly appear on our Earth, for you know, Madame, that the seas are spots. At least, the common opinion is that Sicily was separated from Italy, and Cyprus from Syria. New islands have sometimes formed in the sea. Earthquakes have swallowed mountains, raised others, and changed the course of rivers. Philosophers make us fear that the kingdom of Naples and Sicily, which are lands resting on great underground vaults full of sulfur, may melt away some day, when the vaults are no longer strong enough to resist the fires they hold inside, and which they now let out through vents like Vesuvius and Etna. That's enough to vary the show we put on for the people of the Moon a little."

"I'd much rather," said the Marquise, "bore them by always giving them the same one than entertain them with swallowed provinces."

"That would be nothing," I went on, "compared with what goes on in Jupiter. On its surface there appear what look like bands wrapped around it, and you can tell them apart from each other, or from the gaps between them, by their different degrees of brightness or darkness. They're lands and seas, or at any rate large parts of Jupiter's surface that differ from each other in the same way. Sometimes these bands narrow, sometimes they widen. Sometimes they break up and then join together again. New ones form in various places and others fade away. All these changes, which only our best telescopes can detect, are in themselves far greater than if our Ocean flooded all the dry land and left new continents in its place. Unless the inhabitants of Jupiter are amphibious and live equally on land and in the water, I don't quite know what becomes of them. You also see great changes on the surface of Mars, even from one month to the next. In that little time, seas cover great continents, or draw back with an ebb and flow infinitely more violent than ours, or at least something equivalent. Our planet is very calm next to those two, and we have great reason to be thankful for it, even more so if it's true that in Jupiter countries as large as all of Europe have been set ablaze."

"Set ablaze!" cried the Marquise. "Now that would be real news!"

"Very real news," I said. "About twenty years ago, perhaps, a long band of light was seen on Jupiter, brighter than the rest of the planet. We've had floods here, but rarely. Perhaps on Jupiter they have great fires, also rarely, in addition to the floods, which are common there. But however that may be, this light on Jupiter is not to be compared with another one, which, by all appearances, is as old as the world, and which nobody had ever seen."

"How does a light manage to hide?" she said. "It would take a singular talent."

"This one," I answered, "only shows itself at twilight, so that most of the time the twilight is long enough and strong enough to cover it. And when the twilight does let it show, either the haze on the horizon steals it away, or it's so faint that unless you're very careful, you take it for the twilight itself. But at last, for thirty years now, it has been reliably picked out, and for a while it was the delight of the astronomers, whose curiosity needed to be woken up by something of a new kind. They could have discovered any number of new secondary planets and hardly have been moved. The last two moons of Saturn, for example, didn't charm or enchant them the way the satellites, the moons, of Jupiter did. We get used to everything. So for a month before and after the spring equinox, once the Sun has set and the twilight is over, you can see a certain whitish light that looks like a comet's tail. You can see it before sunrise, and before dawn around the September equinox, and you can see it evening and morning around the winter solstice. Outside those times it can't, as I just told you, be separated from the twilight, which is too strong and lasts too long. For it's supposed to be always there, and everything about it looks that way. People are beginning to guess that it's produced by some great mass of rather thick matter surrounding the Sun out to a certain distance. Most of the Sun's rays pierce through this enclosure and come to us in a straight line. But some, striking the inner surface of this matter, are thrown back toward us. They reach us at times when the direct rays either can't reach us yet, in the morning, or can't reach us anymore, in the evening. Since these reflected rays start from higher up than the direct rays, we have to get them earlier and lose them later.

"On that basis, I have to take back what I told you, that the Moon shouldn't have any twilight because it isn't surrounded by thick air the way the Earth is. It won't lose out. Its twilight will come from this kind of thick air around the Sun, which sends its rays back to places the ones coming directly from it can't reach."

"But doesn't that also give," said the Marquise, "guaranteed twilight to all the planets? They won't each need to be wrapped in a heavy air of their own, since the air around the Sun alone can do that for every planet in the vortex. Given the leaning toward economy that I know nature has, I'd quite willingly believe she used only this one means."

"And yet," I replied, "despite that economy, our Earth would have two causes of twilight. One of them, the Sun's thick air, would be rather useless, and could only be an object of curiosity for the people in the observatory. But to tell the whole story, it may be that only the Earth pushes out of itself vapors and exhalations coarse enough to produce twilight. And nature would have been right to provide by a general means for the needs of all the other planets, which will be, so to speak, purer, and whose evaporations will be subtler. Perhaps we are the ones, out of all the inhabitants of the worlds in our vortex, who needed to be given the coarsest, thickest air to breathe. With what contempt the inhabitants of the other planets would look at us if they knew that!"

"They'd be wrong," said the Marquise. "No one is to be despised for being wrapped in thick air, since the Sun itself has some wrapped around it. Tell me, please, isn't this air produced by certain vapors that you once told me come out of the Sun? And doesn't it serve to soften the first force of the rays, which might otherwise have been excessive? I can imagine that the Sun might naturally be veiled, so as to be better suited to our needs."

"There, Madame," I answered, "is the small beginning of a system, and you've made it quite happily. One could add that these vapors would produce a kind of rain that fell back into the Sun to cool it, the same way people sometimes throw water on a forge when the fire is too fierce. There's nothing you shouldn't assume about nature's skill. But she has another, very particular kind of skill in hiding from us, and we shouldn't be too quick to feel sure we've guessed her way of working, or her designs. With new discoveries, we shouldn't hurry too much to theorize, even though we always have plenty of desire to. True philosophers are like elephants, which, when they walk, never put the second foot down until the first is planted firmly."

"The comparison seems all the more apt to me," she interrupted, "because the merit of both kinds, elephants and philosophers, has nothing to do with outward charm. I'm willing to copy the judgment of both. Tell me a few more of the latest discoveries, and I promise not to build a hasty system."

"I've just told you," I answered, "all the news I know from the sky, and I don't think there's any fresher. I'm sorry it isn't as startling and marvelous as some observations I was reading the other day in a summary of the Annals of China, written in Latin. In it you find thousands of stars at once falling from the sky into the sea with a great crash, or dissolving and going off in rain. That wasn't seen only once in China. I found the observation at two rather distant times, not counting a star that goes off in the east and bursts like a rocket, again with a great noise. It's a pity that those sights are reserved for China, and that our countries have never had their share. It wasn't long ago that all our philosophers believed they had experience on their side when they claimed that the heavens and all the heavenly bodies were incorruptible and incapable of change. And all that time, other men at the other end of the Earth were watching stars dissolve by the thousands. That's quite a difference."

"But," she said, "haven't I always heard that the Chinese were such great astronomers?"

"That's true," I said. "But the Chinese have gained from being separated from us by a long stretch of land, just as the Greeks and Romans have from being separated from us by a long run of centuries. Any distance has the right to impress us. In truth, I keep believing more and more that there's a certain genius which has never yet gone beyond our Europe, or at least hasn't strayed far from it. Perhaps it isn't allowed to spread over a great expanse of land at once, and some fate has drawn rather narrow limits for it. Let's enjoy it while we have it. The best thing about it is that it doesn't shut itself up in the sciences and dry speculation. It extends with equal success to matters of pleasure and taste, in which I doubt that any people equals us. Those, Madame, are the things that are yours to take up, and they should make up all of your philosophy."