What was it that made the motions of the paramecium under the microscope different from the random movement of the particles amongst which they moved.  Vitality was puzzling to me, and I suppose that intelligence and will was an even more puzzling version of the same thing but it was simply an aspect of vitality.

But by the time I went to Cambridge and was using Baldwin's Dynamic Aspects of Biochemistry, I was exposed to a biochemistry which had already, 30 or 40 years earlier, had precluded the necessity for invoking a vital principle. The energetics of oxidative respiration explain where the energy came from.  It wasn’t necessary to invoke some sort of immaterial principle, and the last person I suppose to invoke that notion of a vital principle was Driesch, and that would’ve been about 1910.  But after 1910 I don’t think anyone who was a serious biologist ever thought in terms of a vital principle because biochemistry had actually begun to reveal how the energetics of cells was implemented.

I mean, it’s complicated and quite mysterious but it isn’t mysterious in the way that people who want there to be a deeply and incorrigibly mysterious principle is at work.  It’s mysterious only in that it’s complicated and therefore it’s quite hard to understand how it works. But once I was exposed to Kreb's notion of the tricarboxylic acid cycle one began to see how oxygen got into the system and what it did with carbohydrates and phosphorylation and energy rich bonds and so forth… explained how it was that living things were different from inanimate particles.

[Q] Fabulous really, of course. Did the Origin of Species and Darwin matter to you?

It didn’t matter to me in the sense that it must’ve mattered to people, I suppose, between 1860 and about 1900, by which time natural selection had begun to suffer quite a reversal and people had begun to revert to a more Lamarckian explanation. But by the time the evolutionary synthesis, the new synthesis, as it was called, under the auspices of people like Huxley and so forth had begun to emerge in the ‘30s, it wasn’t an important principle any more than, as it were, Newtonian Physics was an important principle. It was simply a presupposition upon which all one's more interesting and original observations took place.  One didn’t have to argue about it, I mean, it’s only in the last 15 or 20 years that one has to argue against creationists and exponents of intelligent design that one finds oneself rather wearily going back and, as it were, defending Darwin.

I never found myself thinking that Darwin had changed my life. He'd no more changed my life than Newton had changed my life.  It was quite clear that this was how it worked, and when people say, as they do now, oh, it’s only a theory, you rather wearily say, well, look, most of the things in science are in fact only theories.  It isn’t because in fact there’s something which… there’s an alternative of absolute certainties, all science… I mean, you might call the atomic theory, they’re entities that we never meet. We infer their existence but the question is is the increasing probability of the correctness of the theory.  And the same thing applies to Darwinism. It’s hardly worth calling it Darwinism any more than one calls the physical principles which determine the way in which intergalactic flight is performed… no one, as it were, refers to Newton in order to justify the design of rockets. I mean, way back it’s based on Newtonian principles and the laws of motion, but people don’t defensively defer to Newton in order to explain their physics. And I don’t think anyone really now defensively defers to Darwin until they encounter, in a rather weary sort of irritation, people who say that natural selection and evolution is only a theory. But that’s not because one's confronted by a serious alternative which has to be argued about, you’re confronted by a frivolous idiocy which has a very large amount of unjustified publicity.