My father was a great student of the classics and history and philosophy, at the same time he was a friend of nature and this was equally true of my mother. Every weekend we would go out and study nature. In the spring we would look for spring flowers. My father knew where there some limestone quarries where one could find some interesting fossils. He learnt there was a heron colony nearby, so we went to that one day. My mother knew all the mushrooms, so I had a very good all around education in natural history. In fact, I can say that I was a naturalist from the time on that I could walk. And being a naturalist is very important. I can see this all the time in my studies in the history of biology: [Charles] Darwin was a naturalist, in fact he says so in his autobiography: 'I was born a naturalist', he said. His famous friend, TH Huxley, was not a naturalist and it becomes very clear when you read Huxley's writings that whenever it really depended on... on true understanding of nature, Huxley didn't have it because he wasn't trained as a naturalist. And you find it even among more recent authors. For instance, the palaeontologist [George Gaylord] Simpson, with whom I jointly taught a course at Harvard [University] and he was a very good friend of mine. I very often, sort of, noticed that there was something lacking in his understanding and when I somewhat recently looked at his species definition – his so-called evolutionary species definition – I said to myself, if he were a naturalist, or had been a naturalist, he couldn't have made that definition. And I went to his biography, sure enough I found that he had gone to college as an English Literature major, and only in the... in the senior class in college had he become interested in geology and eventually in palaeontology, and he never had that feeling for species that a naturalist has.