The first Darwin Lecture was given in 1977 by Karl Popper. He there said that he had known Darwin's face and name ‘for as long as I can remember’ (‘NSEM’ p. 339); for his father's library contained a portrait of Darwin and translations of most of Darwin's works (‘IA’, p. 6). But it was not until Popper was in his late fifties that Darwin begin to figure importantly in his writings, and he was nearly seventy when he adopted from Donald Campbell the term ‘evolutionary epistemology’ as a name for his theory of the growth of knowledge (OK, p. 67). There were people who saw evolutionary epistemology as a major new turn in Popper's philosophy. I do not share that view. On the other hand, there is a piece from this evolutionist period which I regard as a real nugget.

I call it The Spearhead Model of evolutionary development. It appeared briefly in the Herbert Spencer lecture he gave in 1961, which he wrote in a hurry and left in a rough and unready state. It contained mistakes that would, and did, dismay professional evolutionists. Peter Medawar advised him not to publish it, and it lay around unpublished for over a decade. He eventually published it, with additions but otherwise unrevised, in Chapter 7 of Objective Knowledge. It did not, so far as I know, evoke any public comment from biologists or evolutionists.