On “Micromégas” (1752)

So here’s a remarkable thing. Mars has two moons. That’s not the remarkable thing (although, you know: I suppose in a sense it is) — though these moons, Phobos and Deimos, were not discovered until 1877:

Asaph Hall discovered Deimos on 12 August 1877 at about 07:48 UTC and Phobos on 18 August 1877, at the US Naval Observatory (the Old Naval Observatory in Foggy Bottom) in Washington, D.C., at about 09:14 GMT.

But here’s Micromégas, Voltaire’s 1752 (maybe 1751: scholars aren’t sure when the first edition was published) conte philosophique. In this story the eponymous giant is an alien being from the star Sirius, an entity with the impressive dimensions of 25 miles height, and 8000 times the intellectual capacity of a human being. He travels across space to our solar system. First of all he meets an inhabitant of Saturn who, being barely 1 mile tall, he considers a dwarf. Then the two travel on together, to examine Earth and its microscopic inhabitants. On the way they pass Mars:

En sortant de Jupiter, ils traversèrent un espace d’environ cent millions de lieues, et ils côtoyèrent la planète de Mars, qui, comme on sait, est cinq fois plus petite que notre petit globe; ils virent deux lunes qui servent à cette planète, et qui ont échappé aux regards de nos astronomes. Je sais bien que le père Castel écrira, et même assez plaisamment, contre l’existence de ces deux lunes; mais je m’en rapporte à ceux qui raisonnent par analogie. Ces bons philosophes-là savent combien il serait difficile que Mars, qui est si loin du soleil, se passât à moins de deux lunes.

Upon leaving Jupiter they traversed a space of around one hundred million leagues and approached the planet Mars, which, as we know, is five times smaller than our own; they swung by two moons that cater to this planet but have escaped the notice of our astronomers. I know very well that Father Castel will write, perhaps even agreeably enough, against the existence of these two moons; but I rely on those who reason by analogy. These good philosophers know how unlikely it would be for Mars, so far from the sun, to have gotten by with fewer than two moons.

How did Voltaire know that Mars had two moons, a century and a half before they were first observed?

The answer is: Fontenelle.

The remarkably long-lived Bernard Le Bovier de Fontenelle (he died in 1757, a mere month before his hundredth birthday) was a major figure of French 17th and 18th-century science, perpetual secretary of the Académie des Sciences in Paris, author of many books on all manner of topics. A generation older than Voltaire, he published some of his most famous works before the later author was even born: Nouveaux dialogues des morts (1683) De l’origine des fables (1684), Histoire des oracles (1687) Digression sur les anciens et les modernes (1688) and perhaps his most famous work, Entretiens sur la pluralité des mondes (1686; revised 1724). Part of this latter work was a speculation about the function of moons as such. Why is it, Fontenelle asks, that Mercury and Venus have no moons, Earth one and Jupiter and Saturn many? It must be — or so he reasons — that God, or providence, furnishes these moons to light up what would otherwise be a lightless night sky, for the benefit of the inhabitants of these worlds. The further away from the sun, the fainter sunlight, the darker the night, and therefore the more moons are needful for this task. But wait!

Mais attendez; il me semble que Mars, qui est encore plus éloigné du soleil que la terre, n’a point de lune.

But wait: it strikes me that Mars, further away from the sun than Earth, doesn’t have a moon.

What gives? Fontenelle speculates that perhaps Martian rocks are luminous, absorbing sunlight during the day and releasing it at night (‘Peut-être Mars a-t-il de grands rochers fort élevés, qui sont des phosphores naturels, et qui prennent pendant le jour une provision de lumière qu’ils rendent pendant la nuit’) but a simpler solution is obvious: Mars does have moons, it’s just that we haven’t yet seen them. And if it does have moons, it must, being further from the sun, have more moons than Earth. Voilà!

That Voltaire was engaging with Fontenelle in Micromégas isn’t news. It’s long been known that the mile-high-man from Saturn whom Micromegas first meets when he comes to our solar system, the ‘secretary of the Saturnian scientific society’ is a caricature of Fontenelle. Like F., our Saturnian ‘dwarf’ — a disparaging kind of name, until we remember that he’s only a dwarf when compared to the 25-mile-high Micromegas — is a scientist. When he does come to Earth, he observes the ‘intelligent atoms’ that inhabit that tiny world (us, of course) through a microscope. At one point he thinks he sees humans having sex:

The Saturnian, passing from an excess of incredulity to an excess of credulity, thought he saw them mating. “Ah” he said. “I have caught nature in the act.” But he was fooled by appearances, which happens only too often, whether one is using a microscope or not.

The French phrase here is: j’ai pris la nature sur le fait, a nicely comic double-entendre that means both ‘I have observed the workings of nature’ and also ‘I have seen nature fucking’. It’s based on a line from Fontenelle’s eulogy for Joseph Pitton de Tournefort [Éloge de Tournefort (1708), 54–55]. Botanist Tournefort (and a colleague) had travelled around the Mediterranean and the near East, making a series of observations and discoveries:

Tournefort eut la sensible joie d’y voir une nouvelle espèce de jardin, dont toutes les plantes étaient différentes pièces de marbre encore naissantes ou jeunes ... En vain la nature s’était cachée dans des lieux si profonds et si inaccessibles pour travailler à la végétation des pierres; elle fut, pour ainsi dire, prise sur le fait par des curieux si hardis.

Tournefort had the particular joy of discovering in those places a wholly new kind of garden, all the plants of which were growing in various crenulations and crevices of marble … In vain had nature hidden herself in places so deep and so inaccessible to work on the vegetation of the stones; she was, so to speak, caught in the act by such bold onlookers.

People laughed, here, at Fontenelle’s inadvertent double-entendre, and Voltaire mockingly stuck it into his text.

Ira Wade thinks the extent to which Micromégas is all about making fun of Fontenelle can be overstated:

It is possible to exaggerate the role played by Fontenelle in the Micromégas. It is true that the flowery language of the Secretary of the Academy of Saturn suggests Fontenelle’s much criticized style. The expression J’ai pris la nature sur le fait was a witticism connected with Fontenelle. All in all, however, Voltaire’s barbs at Fontenelle are not particularly severe. They indicate not so much a decided antagonism, or a deep animosity, but rather a passing irritation. [Ira Wade, Voltaire’s Micromégas: a Study in the Fusion of Science, Myth and Art (Princeton University Press, 1950), 24]

As Wade notes, ‘Fontenelle was Secretary of the Academy of Sciences, and Voltaire at the time had ambitions in that direction’ which Fontenelle did not facilitate, although the specific focus of irritation was — it seems — Fontenelle’s comment upon reading Voltaire’s Eléments de la philosophie de Newton (1738). He is supposed to have said, ‘very good, Monsieur Voltaire: another three years of study, and perhaps you will actually begin to understand Newton.’ Ouch!

I’m more interested in what the presence of Fontenelle means for Micromégas as a text. Everybody knows that Candide (far and away Voltaire’s most famous work of course) was a satire upon Leibniz’s facile optimism, and his belief that all must be for the best in this, the best of all possible worlds. But there have been plenty of readers of Micromégas who haven’t grasped that it’s a satire on Fontenelle. Of course, Leibniz is still a famous name in philosophy, and few people remember Fontenelle. But there’s more.

Come at it again: Micromégas is a 25-mile-high giant from the star Sirius, who flies easily around the galaxy examining all he finds with scientific passion and disinterest, making all manner of brilliant discoveries. His Saturnian companion is, by comparison, a dwarf, a significant figure (a mile high) but by comparison with the illustrious Micromégas a nobody, a pigmy. If the Saturnian is Fontenelle, then who is Micromégas himself?

It can only be: Newton. Just as Candide is a novel spun out of Voltaire’s engagement with Leibniz, so Micromégas is novel that renders Newton’s magnitude into a science-fiction fable. How does our hero travel? Like Newton, ‘il connaissait merveilleusement les lois de la gravitation, et toutes les forces attractives et répulsives’ (he had a marvellous understanding of the laws of gravity and all attractive-repulsive forces).

Il s’en servait si à propos, que, tantôt à l’aide d’un rayon du soleil, tantôt par la commodité d’une comète, il allait de globe en globe lui et les siens, comme un oiseau voltige de branche en branche.

He made use of it so aptly that, now with the aid of a ray of starlight, now by the convenience of a comet, he went from planet to planet, he and those like him, like a bird fluttering from branch to branch.

Why, then, Sirius? And why Saturn? Because, in one of his more famous experiments, Newton in the 1670s measured the relative brightness of precisely those two bodies, with a view to establishing their relative distances from Earth via the inverse square law:

In observing the night sky, Newton noted that Sirius was about as bright as the planet Saturn. Observations of Mars by John Flamsteed in 1672 had established that Saturn is about 9–10 times farther from the Sun than Earth, so Newton could use that to determine the distance to Sirius. Sirius and Saturn appeared equally bright, but Sirius was much farther away.

The catch was that Sirius, being a star, emits its own light like the Sun, but Saturn shines by reflecting sunlight. So Newton had to calculate how much sunlight would reach Saturn. This is pretty easy to do with the inverse square law, but Saturn also doesn’t reflect all of the light that strikes it, so Newton had to estimate the fraction of light the planet reflects (known as its albedo).

In the end, Newton calculated that Sirius was about 800,000 times the distance of Earth from the Sun, or about 12.6 light years. The actual distance is about 8.6 light years, so Newton was at least in the ballpark. His biggest mistake was greatly underestimating the albedo of Saturn, but he also assumed Sirius was the same brightness as the Sun, when it is actually much brighter.

Whatever beef he had with Fontenelle, Voltaire had the highest opinion of Newton. In the words of Julia Epstein, ‘Voltaire’s portrait of Newton in the Lettres philosophiques and in his Elemens de la philosophie de Newton presents one of the most dynamic images of the scientist as a hero and as a creative imagination. In 1732, Voltaire wrote to Maupertuis: “[Newton] est notre Christophe Colomb. Il nous a menez dans un nouveau monde, et je voudrois bien y voiager …” [Epstein, ‘Voltaire’s Myth of Newton’ 27]. Elsewhere he called Newton “le dieu au quel je sacrifie” and “l’esprit créateur” (it’s from Voltaire, incidentally, that we get the apocryphal story of Newton ‘discovering’ gravity when an apple falls in his head). Newton is micro- because he was, in himself, physically small (as a child his mother used to say he was tiny enough to fit inside a quart pot), but -megas because he was a giant of science. Newton is Micromegas.