The Salmon of Doubt

I can imagine Newton sitting down and working out his laws of motion and figuring out the way the universe works and with him, a cat wandering around. The reason we had no idea how cats worked was because, since Newton, we had proceeded by the very simple principle that essentially, to see how things work, we took them apart. If you try to take a cat apart to see how it works, the first thing you have in your hands is a nonworking cat. Life is a level of complexity that almost lies outside our vision; is so far beyond anything we have any means of understanding that we just think of it as a different class of object, a different class of matter; “life,” something that had a mysterious essence about it, was God-given—and that’s the only explanation we had. The bombshell comes in 1859 when Darwin publishes the Origin of Species. It takes a long time before we really get to grips with this and begin understand it, because not only does it seem incredible and thoroughly demeaning to us, but it’s yet another shock to our system to discover that not only are we not the centre of universe and we’re not made of anything, but we started out as some kind of slime and got to where we are via being a monkey.

It just doesn’t read well. But also, we have no opportunity to see this stuff at work. In a sense Darwin was like Newton in that he was the first person to see underlying principles really were not at all obvious, from the everyday world in which he lived. We had to think very hard to understand the nature of what was happening around us, and we had no clear obvious everyday examples of evolution to point to. Even today that persists as a slightly tricky problem if you’re trying to persuade somebody who doesn’t believe in all this evolution stuff and wants you to show him an example—they are hard to find in terms of everyday observation. So we come to the third age of sand. In the third age of sand we discover something else we can make out of sand—silicon. We make the silicon chip—and suddenly what opens up to us is a universe not of fundamental particles and fundamental forces, but of the things that were missing in that picture that told us how they work; what the silicon chip revealed to us was the process.

The silicon chip enables us to do mathematics tremendously fast, to model the—as it turns out—very, very simple processes that are analogous to life in terms of their simplicity; iteration, looping, branching, the feedback loop that lies at the heart of everything you do on a computer and at the heart of everything that happens in evolution—that is, the output stage of one generation becomes the input stage of the next.

Suddenly we have a working model—not for a while, because early machines are terribly slow and clunky—but gradually we accumulate a working model of this thing that previously we could only guess at or deduce—and you had to be a pretty sharp and a pretty clear thinker even to divine it happening when it was far from obvious and indeed counterintuitive, particularly to as proud a species as we.

So, suddenly, evolution ceases to be such a real problem get hold of. It’s rather like the following scenario: One Tuesday a person is spotted in a street in London, doing something criminal. Two detectives are investigating, trying to work out what happened. One of them is a twentieth-century detective and the other, by the marvels of science fiction, is a nineteenth-century detective. The problem is this: The person who was clearly seen and identified on the street in London on Tuesday was seen by someone else, an equally reliable witness, on the street in Santa Fe on the same Tuesday. How could that possibly be? The nineteenth-century detective could only think it was by some sort of magical intervention. Now, the twentieth-century detective may not be able to say, “He took BA flight this and then United flight that”—he may not be able to figure out exactly which way he did it, or by which route he traveled, but it’s not a problem. It doesn’t bother him; he just says, “He got there by plane. I don’t know which plane and it may be a little tricky to find out, but there’s no essential mystery.” We’re used to idea of jet travel. We don’t know whether the criminal flew BA 178, or UA 270, or whatever, but we know roughly how it was done. I suspect that as we become more and more conversant with the role a computer plays and the way in which the computer models the process of enormously simple elements giving rise to enormously complex results, then the idea of life being an emergent phenomenon will become easier and easier to swallow. We may never know precisely what steps life took in the very early stages of this planet, but it’s not a mystery.