I took Marxist philosophy very seriously, as we all did. And Marxist philosophy should not be rejected as stupid, I mean, Marx was not a stupid man. It was a... a well articulated, reasoned, philosophical view about the world, it is. And there's no question that... that classical Mendelian genetics was damned undialectical. I speak of dialectical materialism as a philosophy of Marxism. What it says, if you think about it, is that genes determine development in an embryo, but development has no influence on genes. And, I mean, you and I actually believe that to be true, essentially. But this is pre Watson and Crick, remember, we had no molecular understanding of how it could be that a gene could influence development but not be influenced by it. And I was... even after I'd lost my faith in what the Soviet Union was doing and was highly critical of it, I was still enough of a Marxist to feel that... that there was something very suspect about the classical Mendelian attitude in genetics. And indeed, I spent a substantial amount of time doing an experiment which was not, so to speak, intended to demonstrate the falsity of the inheritance acquired characters, but was deliberately looking for a situation in which an acquired character would be inherited. And I thought to myself, what I need is a trait which affects every cell of the body, not just, you know, some external organ, something which is clearly adaptive, it's not the result of damage, and something which I can find in Drosophila where I can do decent genetics. And I looked, in fact, to temperature acclimatisation. I did quite a bit of work on the acclimatisation of fruit flies to a change of temperatures. I showed that they can acclimatise during their lifetime. And then I bred from flies that I'd acclimatised, and compared them with flies that I'd not acclimatised. And it will not surprise you to learn that there was no difference, in other words, the acquired character was not inherited. Curiously, I never published it, because, in a sense, a negative was of no interest except to me, and the rest of the world knew that the negative was to be expected, so I doubt if I could have published it, even actually. But I did take it seriously enough to design an experiment which, if there was any sense in the Lamarckian position, ought to have worked, and it didn't.