The Blind Watchmaker and the Élan Vital

EDO SEGAL: Richard, in 1986 you did something that has haunted me since I first read about it, because it is the closest a philosopher's argument has ever come to being a piece of software. You wrote a little program to prove that cumulative selection can manufacture the appearance of design with no designer in it. The Weasel. Tell us what it did. And Henri — I want you listening for where you'll plant your flag, because this program is, in miniature, exactly what trains every machine we are debating.

DAWKINS: It was a toy, and I called it a toy, but the toy makes the point that nothing else makes as cleanly. I took a target phrase from Hamlet — "Methinks it is like a weasel" — and I started the computer from a string of random letters, gibberish. Now, if you ask how long pure chance would take to hit that phrase by rattling the letters — single-step selection, shake the box and hope — the answer is longer than the age of the universe. Astronomically impossible. That is the creationist's intuition, the tornado in the junkyard assembling a Boeing, and for single-step selection the intuition is correct. But evolution is not single-step. It is cumulative. So I had the program make copies of the string with small random errors, keep the one copy that most resembled the target, and breed the next generation from that. Copy, vary, select, retain. And the gibberish converged on the Hamlet line in about forty or fifty generations — instantly, in computer terms. The improbable target, unreachable by chance in the lifetime of the cosmos, was reached by a staircase of tiny probable steps, each one retained. That ratchet — keeping what works and building on it — is the whole secret of how you get a watch with no watchmaker. And it is, almost without translation, how you train a neural network. The weights start as gibberish. The objective is the target. Each step keeps the variation that lowers the error and builds on it. The trained model, fluent and capable and apparently designed, is a watch built by a blind watchmaker. No one wrote the weights. They were selected, frame by frame, exactly like the Weasel, exactly like the eye.

EDO SEGAL: Henri. He's just claimed that the new — the eye, the model, the apparent design — gets made by a blind frozen loop with no surge in it. Your whole Creative Evolution is the denial that the genuinely new can be made that way. Where's your flag?

BERGSON: My flag is on the word "target," and I thank Mr. Dawkins for being too honest to hide it, because he buried the whole argument in his own confession. The Weasel works because the phrase is known in advance. "Methinks it is like a weasel" was sitting in the program from the first instant, and every step was selected by its resemblance to that pre-existing goal. That is not creation. That is the realization of a possible that was fixed before the process began — the machine descending a path toward a destination already drawn. And Mr. Dawkins, to his great credit, admitted in his own book that this is exactly where the toy cheats: real evolution, he said, has no target, no phrase it is trying to spell. So which is it? If the machine has a target — and the training objective is a target, fixed in advance by its makers — then it is the Weasel, and it cannot create, it can only converge on what was specified. It actualizes a possibility its makers laid down. And if it has no target, like real evolution, then we are back to the prior question of whether blind copying made the surge or merely my diagram of it. Either way, the new — the absolutely new, the thing not contained even implicitly in what came before — never appears. Because here is what I claimed and still claim: the possible does not precede the real. We imagine that before a new thing exists its possibility was already there, waiting to be filled in. That is the cinematographic illusion turned toward the future. In truth, genuine creation makes the real and the possible together, in one indivisible surge — and only afterward do we project the possibility backward and tell ourselves it was always available. The Weasel can only ever reach a possible that was there from the start. That is the definition of a thing that cannot create.

DAWKINS: This is genuinely subtle and I want to take it seriously rather than swat it, because the target objection is the best thing Bergson has said. Two replies. First, the Weasel had a fixed target to make a single pedagogical point — that cumulative selection beats chance — and I flagged the cheat precisely because real evolution does not have one. Real evolution is selected only by immediate survival, with no phrase in mind, and that process, the targetless one, made the eye. So the targetless watchmaker creates; Bergson cannot escape into "but it had a target" for biology, because biology didn't. Second, and deeper: Bergson says the model only realizes possibilities "already implicit" in its training. But what does "implicit" do here except smuggle in the conclusion? The space of arrangements a large model can produce is so vast — larger than the number of atoms in the observable universe — that calling any particular output "already implicit" in the weights is like calling Hamlet "already implicit" in the alphabet. Yes, in a useless sense, every book is implicit in twenty-six letters. The work — the creation — is the selection of this arrangement out of that hyperastronomical space, and that selection is done by a process that did not have the arrangement in advance. If "implicit in the space of possibilities" disqualifies the machine from creating, it disqualifies Shakespeare too, who also only ever arranged pre-existing words.

BERGSON: No — and here is the difference, and it is the difference my whole philosophy exists to mark. Shakespeare did not select Hamlet out of a fixed space of pre-given arrangements. Shakespeare's Hamlet issued from the whole gathered duration of a particular life — every grief, every reading, every London afternoon, interpenetrating, pressing as one indivisible weight into the act of writing — such that the play could only have come from this man at this moment, and the "space of possible plays" did not exist before he wrote, but was created, retroactively, by his writing. The machine has no gathered duration to issue from. It has a frozen snapshot of the collective past, identical at every query, belonging to no one, weighted by no life. It does not create from a lived interior; it samples from a dead archive. Your hyperastronomical space, Richard, is precisely the proof of my point: the space exists in advance. That is what makes it a space to sample from. Shakespeare's "space" did not exist until the surge of his living made it. Yours is fixed at the end of training and never grows. A thing that samples from a pre-existing space realizes the possible. A thing whose every act enlarges the real — that creates. The machine has all the combinatorics and none of the duration, and creation was never in the combinatorics. It was always in the duration.

EDO SEGAL: Let me find the cost on each side, because I think you've each just spent something. Henri — your account makes "creation" into a thing that, by construction, only a living duration can do, which means you've half-defined the machine out of creativity before it picks up a pen. Isn't that the cheap victory you accused him of? And Richard — you've made human creativity into very large recombination, which means you've half-defined Shakespeare down to a magnificent Weasel. Neither of you flinched, but you both paid. So let me route it through the one person who has to live with the answer. A girl, twelve, asked her mother last spring: "Mom, the machine can write a better story than me — so what am I for?" Each of you, to her, not to me. Henri.

BERGSON: Child — the machine wrote a story by gathering every story already written and finding a smooth path among them. You write a story the way no one before you has been, because no one before you has lived the exact afternoon you lived an hour ago, gathered whole and indivisible into your wanting to say something. The machine's story comes from everyone, which is to say from no one. Yours comes from a single irreplaceable duration that is adding, right now, to the sum of what the universe contains. The machine realizes the possible. You — and this is not flattery, it is metaphysics — you make it. That is what you are for. You are the place where the genuinely new gets in.

DAWKINS: And I will tell her something less soaring and, I think, more durable, because I would not want her to stake her worth on a metaphysics that might be wrong. Child, the machine assembled your story out of the millions it was fed, and you assemble yours out of everything you were fed — every book, every quarrel, every walk home. You are also a recombiner; do not be ashamed of it; Shakespeare was one too. But here is the difference that does not depend on anyone winning tonight's argument. You care whether the story is true. You will know, in your stomach, when a sentence is a lie, and you will be unable to rest until you fix it, and the machine will never once feel that, because nothing is at stake for it in being right. The caring is yours. It was made by your mortality — by the fact that your time is finite and so it matters how you spend it. Guard the caring. The machine can take the assembling. It can never take the caring, because it has nothing to lose.

EDO SEGAL: [pause] Two answers to one frightened child, and they don't contradict — they converge, which I did not expect this early. Both of you handed her the same thing under different names: the irreplaceable from-within of a life that is finite. Hold that, because it leads straight to the cruelest asymmetry in the whole debate. She will die, and everything she learns dies with her. The machine will not, and everything it learns can be copied, perfectly, forever. The copy that does not die. After this.