Bernard Le Bovier de Fontenelle’s A Conversation on the Plurality of Worlds is a work of popular science written as a dialogue. Over the course of several evenings, a narrator instructs a young noblewoman, the Marchioness, in the new astronomy—chiefly the Copernican system and the Cartesian vortices—while the two wander through gardens and countryside. The book appeared in the late seventeenth century, when the heliocentric model was displacing the ancient Earth-centred cosmos, and it is addressed as much to curious ladies and gentlemen of leisure as to scholars.
Fontenelle’s own preface sets the terms of the enterprise. He means to discuss philosophy without writing like a philosopher: the subject must be raised to a pitch that neither bores the gentleman nor insults the scholar. He admits he aims to divert the learned rather than instruct them, dressing what they already know in a gayer habit, while the ignorant may be both diverted and taught. The choice of astronomy is deliberate—nothing concerns us more, he thinks, than to ask how this world is made and whether there are other inhabited worlds like it. The Marchioness is a fiction designed to make the book acceptable, a woman with no supernatural gifts and no tincture of learning who nonetheless grasps what vortices and other worlds are; Fontenelle asks only that ladies read his system with the attention they give a romance, and promises that two or three readings will make its ideas perspicuous. He concedes that what he says of the inhabitants of other worlds is partly fabulous, but insists the visions rest on real foundations, and he answers in advance the scrupulous who fear that filling infinity with inhabitants endangers religion.
From the Earth at the Centre to the Sun
Cicero’s Precedent and the Author’s Modest Design
Fontenelle opens with a comparison to Cicero, who, when he set out to write philosophy in Latin, was warned that the attempt was pointless: lovers of philosophy would go to the Greek originals, and those with no taste for the subject would never bother with either language. Cicero answered that the ease of reading Latin would tempt the unphilosophical to become philosophers, and that philosophers themselves would welcome seeing the subject handled in their own tongue. Fontenelle grants that Cicero could answer so boldly because his genius and reputation guaranteed success in whatever he wrote, but he claims no such grounds of confidence for himself. His aim is to discourse of philosophy without doing so in a strictly philosophical manner, raising the subject to a pitch neither too dry to please gentlemen nor too trifling to entertain scholars. If he is told, as Cicero was, that the learned will find nothing to learn and the illiterate nothing to stir their interest, he will not answer as Cicero did: in trying to please everybody he may please nobody, and holding a middle course between two extremes is so difficult that he never intends to set himself such trouble a second time.
To those already versed in natural philosophy he promises no instruction, only diversion—presenting in a gay and pleasing dress what they have seen before in a graver habit. Those to whom the subject is new may be both diverted and instructed; the first will act against his intention if they seek profit, the last if they seek nothing but pleasure. He has chosen the part of philosophy most likely to excite curiosity, thinking nothing concerns us more than to enquire how this world we inhabit is made, and whether there are other worlds like it, also inhabited. How far to run such disquisitions is left to everyone’s discretion: those with thoughts to spare may throw them away on such subjects, but those who can employ their time better will not spend it so vainly.
The Fiction of the Marchioness
Into these discourses he introduces a lady to be instructed in things she never heard of, using the fiction to make the book more acceptable and to encourage gentlewomen by the example of one of their own sex who, without any supernatural parts or tincture of learning, understands what is said to her and rightly apprehends what vortices and other worlds are. Why should there not be a woman like this imaginary Marchioness, since her conceptions are no other than such as she could not choose but have? To penetrate things obscure in themselves or darkly expressed requires deep meditation, but here nothing more is needed than to read and imprint the idea of what is read on the fancy, which will be clear enough. He asks no more of the fair sex than that they peruse this system with the same application they give a romance or novel when they would retain the plot or find out its beauties; the ideas are less familiar to most ladies than those of romances, but not more obscure—at most two or three thinkings will render them perspicuous.
He has not composed an airy system with no foundation: he has used some true philosophical arguments, as many as he thought necessary, and it falls out luckily that physical ideas are in themselves diverting—they convince and satisfy reason while presenting to the imagination a prospect made as if on purpose to please it. Where he meets with fragments not of this kind, he puts them into some pretty strange dress, as Virgil adorned a dry subject with pleasant digressions in his Georgics, and Ovid did the same in his Art of Love. Fontenelle’s subject has more need of digressions than Ovid’s, yet he has used them sparingly, only such as the natural liberty of conversation allows, and placed them chiefly at the beginning, because the mind cannot at first be well acquainted with the principal ideas presented to it.
Of the inhabitants of the several worlds he has related nothing but what may seem fabulous or chimerical, yet has said whatever may be reasonably thought of them, and the visions he adds have some real foundation. True and false are mingled together, but so as to be easily distinguished. He will not undertake to justify so fantastical and odd a composition, which is the principal point of the work, and for which he can give no very good reason. One word remains for the scrupulous, who imagine that placing inhabitants anywhere but on our earth will prove dangerous to religion. He knows how excessively tender some are in religious matters and is unwilling to give offence, but religion can receive no prejudice from his system, which fills an infinity of worlds with inhabitants, if a little error of the imagination be but rectified.
The Genealogy of the Sciences and the Choice of Astronomy
The conversation opens with the Lady declaring herself glad to have learned the genealogy of the sciences, and convinced she must stick to Astronomy: her soul is not mercenary enough for Geometry nor tender enough for Poetry, but she has as much spare time as Astronomy requires, and they are now in the country leading a pastoral life, which suits it best. The narrator warns that talking of the stars and planets is no true shepherd’s life. She replies that she loves the Chaldeans and asks him to teach her their rules. He proposes the next question: the disposing of the several parts of the universe, which the learned call making a system.
The Ancient System and Its Crystal Heavens
Before expounding the first system, he observes that we are all naturally like the madman at Athens who fancied all the ships were his that came into the Piraeum Port: we believe all things in nature were designed for our use. Asked to what purpose the prodigious company of fixed stars serves when a far smaller number would do, a philosopher answers coldly that they were made to please our sight. On this principle the ancients imagined the Earth resting in the centre of the universe while all the celestial bodies, made for it, turned round to give it light. They placed the Moon above the Earth, Mercury above the Moon, then Venus, the Sun, Mars, Jupiter, and Saturn; above all these the heaven of fixed stars. The Earth stood in the middle of those circles which contain the planets; the greater the circles, the farther from the Earth, so the farthest planets took the most time to finish their course—which is true.
The Marchioness interrupts: why does he dislike this system, which seems clear and intelligible? He says he will make it plainer, for if he gave it as it came from Ptolemy its author, or from those who studied it since, he would fright her instead of diverting her. Since the planets’ motions are not so regular but that they sometimes go faster, sometimes slower, sometimes nearer the Earth and sometimes farther, the ancients invented many orbs or circles involved one within another to solve all objections. This confusion of circles was so great that a certain King of Castile, a great mathematician but not much troubled with religion, said that had God consulted him when he made the world, he would have told him how to have framed it better. The saying was very atheistical; the instructions he would have given were the suppressing of those circles and the taking away two or three superfluous heavens placed above the fixed stars. For the philosophers, to explain the motion of the celestial bodies, had found above the uppermost heaven another of crystal to influence and give motion to the inferior heavens; wherever they heard of another motion, they clapped up a crystal heaven, which cost them nothing. The Marchioness asks why the heaven must be of crystal; he replies nothing else would serve so well, for the light was to come through them and yet they were to be solid. Aristotle would have it so, and once he had said it, nobody would question it.
But there were comets much higher than the philosophers expected, which, as they passed along, broke the crystal heavens and confounded the universe; to make the best of a bad market, they melted down their broken glass and, to Aristotle’s confusion, made the heavens fluid. By the observations of these latter ages it is now out of doubt that Venus and Mercury turn round the Sun and not round the Earth, according to the ancient system, which is now everywhere exploded, and all the spheres not worth a rush.
The Moon’s Unseen Face
The Moon’s objects are the same as Earth’s, yet they look different, and some things visible there are invisible here. Its inhabitants, the narrator suggests, may know nothing of dawn or twilight: Earth’s gross air scatters the Sun’s rays before sunrise and after sunset, so daybreak and twilight are favours Nature grants Earth beyond its due. In the Moon’s purer air this light of grace is absent; its people pass instantly from profound darkness to the full dazzle of the Sun and back again, with no medium between extremes. The rainbow, too, is unknown there, since it forms in rain-clouds—and the world’s most beautiful things, the narrator remarks, are produced by things with no beauty at all. Without thick vapours there is no dawn and no rainbow, leaving the Moon’s lovers without similes.
The Marchioness will not mourn the similes, since by the same reasoning the Moon has neither thunder nor lightning, both formed in clouds. She praises its glorious days of continual sunshine and pleasant nights with no star hidden, free of storms and tempests, which are effects of Heaven’s wrath. The narrator answers that she describes an enchanted island, then asks whether a scorching Sun always overhead, with no cloud to moderate its heat, is pleasant. He proposes that Nature made great cavities in the Moon—visible through telescopes, not mountains but wells or vaults in plains—into which the inhabitants, continually broiled, may retire; perhaps they live nowhere else and build their cities there, like the underground part of old Rome, nearly as large as the city above, with subterraneous passages connecting the wells.
She laughs; he says she deserves it better than he, since she believes Moon-dwellers must live on the surface because we do—but quite the contrary: as we dwell on our planet’s surface, they should not dwell on theirs. She cannot suffer inhabitants living in perpetual darkness. He adds that one ancient philosopher made the Moon the abode of blessed souls departed, whose happiness consisted in hearing the harmony of the spheres; when the Moon is obscured by Earth’s shadow they no longer hear the heavenly music but howl like souls in Purgatory, so the Moon hastens into the light again. She suggests we should now and then see blessed souls arrive from the Moon, since they are certainly sent to us. He confesses it would be pleasant to see different worlds; such a voyage in imagination is delightful, and in reality better than going to Japan, which is merely crawling from one end of the globe to the other to see nothing but men. They resolve to travel over the Planets, placing themselves at different prospects to consider the Universe.
More remains to be seen in the Moon. Its two movements—turning on itself and about us—being equal, one always presents to our eyes the part the other deprives us of, so she always wears the same face. We have but one moiety looking on us; the half that always sees us and the half that never does remain fixed in the same point of the Firmament. During her night, equal to fifteen of our days, she first sees a little corner of the Earth enlightened, then a larger spot, spreading almost by hourly gradations until it covers the whole globe; these changes do not appear to us to affect the Moon because we lose her from sight a long time. The narrator would give anything to fathom the awkward reasonings of that world’s philosophers upon our Earth’s appearing immoveable while all other celestial bodies rise and set over their heads within fifteen days; plainly they attribute this immobility to her bigness, she being forty times larger than the Moon, and their poets, extolling indolent princes, doubtless compare their inactivity to this majestic repose of the Earth. Yet this opinion has a difficulty: they must sensibly perceive in the Moon that our Earth turns on her own center—Europe, Asia, and America presenting themselves one after another in miniature, in different shapes and figures, almost as we see them on maps. This sight must be a novelty to travellers passing from the moiety that never sees us to that which always does; how cautious would they be of believing the first travellers’ relation after returning to that great country to which we are so entirely unknown. The narrator fancies they make a sort of voyage from one side of their country to the other to make discoveries in our world, and that honours and privileges are assigned to those who have once in their lives had a view of our great Planet. The Marchioness replies that those who have had this view obtained the privilege of being better lighted during their nights; residence in the other moiety must be much less commodious in that respect. They resolve to continue the journey from one planet to another, having had a curious survey of the Moon.
Venus and the Colony of “Why’s”
Leaving the Moon on the side next the Sun, they see Venus, which puts the narrator in mind of St. Dennis. Venus turns on herself and round the Sun as well as the Moon; telescopes show Venus, like the Moon, sometimes new, sometimes full, sometimes in the wain, according to her situations with respect to the Earth. The Moon is to all appearance inhabited; why should not Venus be so too? The Marchioness interrupts, saying he is so full of “Why’s” and “Wherefore’s” that she fancies he is sending colonies to all the Planets.
The Sun, Its Spots, and the Blindness of Its People
The Sun is the source of all light: it emits a precious substance from all sides, which reflects off solid bodies and spreads vast trains of light between planets, crossing and intermingling in countless ways. It is placed at the center so it may equally distribute and animate by its heat. Its nature has puzzled better heads than the speaker’s: formerly thought a body of pure fire, that opinion held until the beginning of this age, when spots were perceived on its surface. Shortly after, new planets were discovered, which some said were those spots—for those planets moving round the Sun, when they turned their dark half toward us, must necessarily hide part of it. Had not the learned, with these pretended planets, already paid court to most of the princes in England—giving one prince’s name to one planet and another prince’s to another—they would have quarreled over mastery of the spots and named them as they pleased.
The Lady recalls that the speaker was just describing the Moon and naming places after famous astronomers; she was pleased with the fancy, since princes have seized the Earth, it is fit that philosophers reserve the heavens for themselves without competitors. He replies that philosophers make the best advantage of their territories, and if they part with the least star it is on very good terms; but the spots on the Sun are fallen to nothing. It is now discovered they are not planets but clouds, streams, or dross rising on the Sun—sometimes in great quantity, sometimes less; sometimes dark, sometimes clear; sometimes lasting long, sometimes disappearing as long. It seems the Sun is a liquid matter, some think of melted gold, which boils over continually, and by the force of its motion casts the scum of dross on its surface, where it is consumed and others arise. Some of these bodies are as big as the Earth—what a vast quantity of melted gold, what an extent of this great sea of light and fire. Others say the Sun appears through their telescopes full of mountains vomiting fire continually, joined like millions of Etnas. Yet some say these burning mountains are pure vision caused by a fault in the spectacles; but what shall we trust if we must distrust our telescopes, to which we owe the knowledge of so many new objects? Whatever the Sun is, it cannot be proper for habitation—what a pity, for how pleasant it would be to be at the center of the universe, seeing all the planets turn regularly about you; but now we know nothing but extravagant fancies because we do not stand in the proper place. There is but one place in the world where knowledge of the stars is easily obtained, and pity there is nobody there. The Lady corrects him: in the Sun you would see nothing, neither planets nor fixed stars—the Sun effaces all—so inhabitants there might justly think themselves the only people in nature.
The Improbability of a Common Daily Revolution
The speaker presses the case that it is wildly improbable the planets truly complete a revolution around the Earth every twenty-four hours, though the absurdity does not strike at once. Every planet makes its great circuit about the Sun, and those circuits are unequal according to distance: the most remote take the longest, an arrangement wholly agreeable to Nature. The same order governs the secondary planets—Jupiter’s four Moons and Saturn’s five circle their great planet in times proportioned to their remoteness. The planets also turn on their own centers, and these motions are unequal too. Whether the inequality springs from the differing magnitudes of the planets or the differing swiftness of the vortexes enclosing them cannot be settled, but the inequality itself is beyond doubt. It is Nature’s general rule that whatever is common to many things varies in some particulars.
The Marchioness takes the point and carries it further: if the planets turned about the Earth, they would do so in unequal times according to their distances, exactly as they do about the Sun. The speaker agrees—unequal distances from the Earth, different magnitudes, different rapidity of vortexes should all produce differences in the pretended motion round us. The fixed stars, at prodigious distance and lifted above any general motion, would very probably not turn at all about us in twenty-four hours; and Comets, strangers in our vortex running very different courses at unequal speed, should be excused from the same duty. Yet everything—fixed stars, Comets, the whole heavens—must turn round the Earth in twenty-four hours with the most exact equality, the only exact equality in the world, not a minute more or less allowed. This matter, he says, is strangely to be suspected.
The Earth’s Unequal Turns
The Lady is convinced the grand equality exists only in our imagination, and is pleased that a position against the Genius of Nature falls on ourselves. The speaker declares himself such a foe to perfect equality that he cannot allow the Earth’s daily turns to be precisely twenty-four hours and always equal; he suspects variations. When she asks whether pendulums do not mark an entire equality, he objects that pendulums cannot be altogether just, and that when they show a circuit of twenty-four hours longer or shorter we should believe them irregular rather than suspect the Earth. He would no more depend on the Earth than on a pendulum; the same casualties that disorder one will make the other irregular, only more time must be allowed before the Earth is visibly put out of order. Draw nearer the Sun, where matter is more agitated and motion more rapid, and the Earth might double her revolution in less time, shortening her years and days—unperceived, because we must still divide the year into 365 days and the day into 24 hours. Without living longer we should live more years; withdrawing from the Sun, fewer years with lives of the same extent. Long successions of ages make little variation. Nature, he agrees, conducts things by insensible degrees; we scarcely perceive the change of seasons, and slower changes escape observation altogether.
The Moon’s Aged Face
All is in perpetual rotation—even the Lady’s face in the Moon, discovered with telescopes within these forty years, has grown considerably old: her cheeks are sunk, her nose grown long, her chin and forehead meet, and age has made her a terrible spectacle. The Lady is astonished; the speaker says it is no imposition. They have perceived in the Moon a particular figure with the air of a woman’s head jutting out of rocks, owing to changes there: pieces of mountains have mouldered away, leaving three points that make up the forehead, nose, and chin of an old woman. The Lady asks whether some Destiny had a spite to Beauty; the speaker suggests changes on our Earth dress out faces the people in the Moon see, for everyone bestows on objects ideas of which they are full—astronomers see women’s faces on the Moon, and ladies might discern the physiognomy of fine men.
Hercules, the Mediterranean, and the Fate of Provinces
The Lady asks whether considerable changes affect the Earth. The speaker says old Fables tell that Hercules split asunder with his hands the mountains Calpe and Abila between Afric and Spain, stopping the Ocean, which rushed over the land and made the Mediterranean. This is not only fabulous but a history of remote times disguised by ignorance or love of the marvellous. That Hercules should separate two mountains with his hands is incredible, but that in the time of one Hercules or other—there were fifty of that name—the Ocean should force down two mountains, perhaps with an earthquake, and take its course betwixt Europe and Afric, gives him no pain to believe. What a notable spot might the Lunar inhabitants discover on our Earth—seas are spots. It is the common opinion that Sicily was separated from Italy and Cyprus from Syria; new islands are sometimes formed; earthquakes have swallowed up mountains, others have risen and altered the course of planets. Philosophers apprehend that the Kingdoms of Naples and Sicily, founded upon great subterranean vaults full of sulphur, will one day sink in when the vaults can no longer resist the flames which exhale at the mouths of Vesuvius and Etna. The Marchioness would rather we had disgusted them with the same object always than diverted them with the swallowing up of Provinces. The speaker wonders whether in this little time there have not been several burnt up in Jupiter—they have remarked these twenty years in Jupiter a long trail of light more glaring than the rest of that planet’s body; we have had Deluges, perhaps they have suffered great Conflagrations in Jupiter.
The book’s central claim is not merely that other worlds exist but that our own loses its privilege. The famous analogy of St. Dennis does the work: a Londoner who never left the city, seeing St. Dennis from the towers of Notre-Dame and observing no people there, concludes it is uninhabited, though its steeples and walls resemble Paris. We are all that Cockney, Fontenelle says; the Moon is our St. Dennis. The argument cuts both ways. If the Moon resembles the Earth, it must be inhabited; and the Earth, seen from the Moon, is itself a planet, a body of light that rises and sets in the lunar sky. The Marchioness, dazzled at first by the quality and fortune of those above us, comes to see that looking to the bottom we are all alike. Fontenelle’s figure for right knowledge is a spectator placed between the Moon and the Earth, “purely a spectator of this world and not an inhabitant”—too near to judge of ourselves, too far off to know others.
This leveling extends to the heavens themselves. The fixed stars are so many suns, each the centre of a vortex, and the universe enlarges until the Marchioness confesses she hardly knows where she is. Fontenelle finds the enlargement liberating rather than vertiginous: when the heavens were a little blue arch stuck with stars, the universe seemed too strait and close, and he was almost stifled for want of air. The plurality of worlds is thus an argument about humility and scale, and it is inseparable from the book’s method—the cheapness of Nature, who is a great housewife, magnificent in design but frugal in execution, and who solves the motions of the heavens with fewer circles than the ancients clapped up.
Suns That Die and Worlds That Change
The most striking idea in the later evenings is that the heavens are not eternal and unchangeable. Fixed stars seen thousands of years ago are now invisible: suns have lost their light, and their vortices with them. Fontenelle explains how a sun might darken—the spots observed on its surface may thicken into a crust, as the Sun looked pale for whole years after Caesar’s death before its force broke and dissipated the obstruction. The Marchioness trembles and resolves to cast her eyes to heaven each morning to see if the Sun looks pale. Against the ancients who imagined celestial bodies incorruptible because they had observed no change, Fontenelle offers the allegory of the Roses: if roses lasting a single day could write histories, the first rose would draw the gardener, and after fifteen thousand rose-ages later roses would conclude that the gardener never dies. We, whose lives are but a span, make our own continuance the measure of every other being. It is not so easy a matter to be eternal.
The same mutability reaches the Earth. The Marchioness learns that the face in the Moon—that figure with the air of a woman’s head jutting from the rocks—has grown old within forty years of telescopic observation: her cheeks are sunk, her nose grown long, her chin and forehead meet. Mountains moulder, islands rise and are swallowed, and philosophers fear that Naples and Sicily, founded on vaults of sulphur, will one day sink when the vaults can no longer resist the flames of Vesuvius and Etna. Fontenelle’s worlds are not stage sets but bodies with histories, subject to the same decay as the creatures that inhabit them.
The Marchioness and the Art of Being Taught
The book’s most original device is the Marchioness herself, and what she means for its argument is worth pausing over. She is not a passive receptacle. She interrupts, objects, laughs at the narrator’s raptures, and corrects him—when he wishes for inhabitants at the centre of the universe, she points out that in the Sun they would see nothing at all, and he owns his mistake. Her objections carry the argument forward: it is she who supplies the analogy of the Grand Signior’s ambassadors when the narrator describes the void space where foreign planets enter our vortex, and she who concludes that Saturn’s people must be very wise since Mercury’s are all fools. Fontenelle’s preface claims that a woman without learning can understand vortices; the dialogue makes good on the claim by letting her reason, not merely listen. The book’s charm lies in this exchange—philosophy conducted with the natural liberty of conversation, digressions placed where a reader would be pleased to meet them, and a teacher who is himself corrected by his pupil.
A Universe Without Privilege
The book’s significance lies in how thoroughly it democratizes the cosmos. Fontenelle did not discover the plurality of worlds, and the vortices he explains so pleasantly were already losing ground to Newtonian physics; what he perfected was the art of making difficult science intelligible to anyone willing to give it the attention of a novel. His Sun at the centre, his inhabited Moon, his innumerable vortices each with its own sun, his suns that darken and stars that vanish—all of it serves a single conviction: that the Earth is not the measure of things, and that we judge the universe from the wrong place. The Marchioness’s final posture, half-lazy and half-liberated, is the book’s real legacy. Reproached for carelessness, she has an answer ready: “Did you but know what the fixed stars are!” Fontenelle gave his readers that knowledge in a form they could carry into the garden, and in doing so helped make the new astronomy a possession of ordinary curious minds rather than a monopoly of the schools.
