WE call him Proteus because, like the sea god in Homer, he “tried to escape his captors by assuming all sorts of shapes.”1 Voltaire called him Pantophilus because Diderot was in love with every branch of science, literature, philosophy, and art. In each of these fields he had intimate knowledge; to each he made suggestive contributions. Ideas were his meat and drink. He gathered them, savored and sampled them, and poured them out in a profuse chaos whenever he found a blank sheet or a willing ear. “I throw my ideas upon paper, and they become what they may”2—perhaps foes. He never co-ordinated them, never bothered with consistency; we can quote him in almost any direction, but his composite direction was unmistakable. He was more original than Voltaire, perhaps because he had never accepted classic norms, and could let himself go without well-bred restraints. He followed every theory wherever it led him, sometimes to its depths, sometimes to its dregs. He saw every point of view except those of the priest and the saint, because he had no certainties.
As for me, I concern myself more with forming than with dissipating clouds, with suspending judgment rather than with judging.… I do not decide, I ask questions.3 … I let my mind rove wantonly, give it free rein to follow any idea, wise or mad, that may come uppermost; I chase it as do young libertines on the track of a courtesan whose face is windblown and smiling, whose eyes sparkle, and whose nose turns up.… My ideas are my trollops.4
Diderot had an intellectual imagination; he visioned ideas, philosophies, personalities, as others vision forms and scenes. Who else in his time could have conceived the scandalous, unmoral, shiftless, fascinating “nephew of Rameau”? After creating a character, he let it develop as of its own accord; he let it lead him on as if the character were the author, and the author the puppet. He imagined himself in the place of a young unwilling nun, and made her so real that skeptical Frenchmen worried over her woes. He experimented mentally with ideas, entertained them for a time, imagined their consequences in logic or action, then tossed them aside. There was hardly an idea of that time that did not enter his head. He was not only and literally a walking encyclopedia, he was a moving laboratory, and his ideas wandered with his feet.
So in Penées sur l’interprétation de la nature, which he published in 1754—anonymously, but with permission tacite from the benevolent Malesherbes—he played with ideas of monism, materialism, mechanism, vitalism, and evolution. Still under Bacon’s spell, he took from him the title, the aphoristic form, and the summons to scientists to labor in concert for the conquest of nature through experiment and reason. He was inspired, too, by Maupertuis’ Système universel de la nature (1751), and Buffon’s Histoire naturelle(1749 f.); he agreed with Maupertuis that all matter might be alive, and with Buffon that biology was now ready to speak to philosophy. He welcomed in both authors the emerging hypothesis of evolution.
He began with a proud design: “It is nature that I wish to describe [écrire]; nature is the only book for the philosopher.”5 He conceived of nature as a half-blind, half-intelligent power operating upon matter, making matter live, making life take a million experimental forms, improving this organ, discarding that one, giving birth and death creatively. In that cosmic laboratory thousands of species have appeared and disappeared.
Just as in the animal and plant kingdoms an individual begins, … grows, endures, perishes, and passes away, could it not be likewise with entire species? If faith did not teach us that animals come from the hands of the Creator such as we see them, and if it were allowed to have the least doubt of their commencement and their end, might not the philosopher, abandoned to his conjectures, suppose that animality had from all eternity its particular elements, scattered and confounded in the mass of matter; that these elements happened to unite, since it was possible for this to happen; that the embryo formed from these elements passed through an infinity of organizations and developments; that it acquired in succession movement, sensation, ideas, thought, reflection, consciousness, feelings, passions, signs, gestures, articulate sounds, language, laws, sciences, and arts; that millions of years passed between these developments; that perhaps it [the organism] has still further developments to undergo, other additions to receive, now unknown to us; … that it may lose these faculties as it acquired them; that it may forever disappear from nature, or, rather, continue to exist under a form, and with faculties, quite other than those which we notice in it in this moment of time?6
Nature in Diderot is everything; she is his God; but of her essence we know only her confused abundance and restless change. Nature is matter alive. Everything is matter, but matter contains in itself the élan of life and the potentiality of thought. Man is not a machine, but neither is he an immaterial spirit; body and soul are one organism, and die together. “Everything destroys itself and perishes; nothing remains but the world; nothing endures but time.”7 Nature is neutral: she makes no distinction between good and evil, great and small, sinner and saint. She cares for the species rather than for the individual; let the individual mature and reproduce, then let him die; and every species too will die. Nature is wise in a myriad subtle details, which seem to show design; she gives organisms instincts that enable them to live and make live; but also she is blind, destroying philosophers and fools alike with one belch of fire, one heave of her shoulders through the crust of the earth. We shall never be able to understand Nature, or to ferret out her purpose or meaning, if she have any; for we ourselves, in all our bloody and majestic history, are among her transient and infinitesimal sports.