sign in sign up
<<
Home , Herbert Spencer

John Watkins

POPPER AND

I

The first Darwin Lecture was given in 1977 by . He there said that he had known Darwin’s face and name “for as long as I can remember” (1978, p. 339); for his father’s library contained a portrait of Darwin and of most of Darwin’s works (1974, 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 ” as a name for his theory of the growth of knowledge (1972, p. 67). There were people who saw evolutionary epistemology as a major new turn in Popper’s philosophy.1 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 Peter Medawar advised him not to publish it,2 and it lay around unpublished for over a decade. He eventually published it, with additions but otherwise unrevised, in Chapter 7 of Objective Knowledge (1972). It did not, so far as I know, evoke any public comment from or evolutionists. I touched on it briefly in my contribution to the Schilpp volume, but I know of no other published discussion of it. When I discussed the neglect of Popper’s Herbert Spencer lecture with Bill Bartley, in 1978, he was pretty dismissive, saying that it was all in Alister Hardy. Now it is true that much of that lecture is about an idea,

1 I am thinking especially of the late Bill Bartley; see Radnitzky & Bartley (1987), part 1. 2 He is the expert mentioned by Popper on p. 281 of his (1972).

In: E. Suárez-Iñiguez (ed.), The Power of Argumentation (Poznań Studies in the Philosophy of the Sciences and the Humanities, vol. 93), pp. 101-116. Amsterdam/New York, NY: Rodopi, 2007.

102 John Watkins which Popper was later (1982, pp. 39f) to call “active Darwinism,” which had indeed been anticipated by Hardy. Hardy had suggested that an animal’s interests might change in such a way that certain bodily mutations that would previously have been unfavourable now become favourable; and he added that while such a change of interest might be forced upon the animal by external circumstances, it might result from exploratory curiosity and the discovery of new ways of life. He gave the example of forebears of the modern woodpecker switching their attention from insects in the open to insects in the bark of trees. No doubt these proto-woodpeckers proceeded rather clumsily at first; but going after this rich new food supply with tools not well adapted to the task proved at least marginally more rewarding than persisting with old habits. So new habits developed; and mutations that made the bird’s bodily structure better adapted to these new functions now became advantageous, though they would previously have been disadvantageous. So new shapes of claws, beak, tongue, etc., began to evolve. Popper put forward the same idea, together with the woodpecker example, without reference to Hardy. But I am sure that Popper was entirely innocent here. He gave this lecture in 1961. Hardy presented the idea in his book The Living Stream (1965). Before that he had broached it in the Linnean ’s Proceedings in 1957, but Popper would not have seen that. If Popper made a mistake it was to publish this lecture essentially unrevised in 1972. When he sent Hardy a copy of Objective Knowledge he apologized for its lack of any reference to him.3 He made ample amends later in his (1975), (1977), and (1982). In any case the Spearhead Model is distinct from “active Darwinism.” It is about certain relations between an animal’s central control system and its motor system. Popper was usually a good publicist for his own ideas, and he subsequently gave plenty of publicity to the idea of “active Darwinism.” But he allowed the Spearhead Model to fall into neglect. I will resurrect it. In case you are wondering whether a neglected contribution to evolutionary theory is a suitable subject for a philosophical lecture, I may add that the Spearhead Model has important implications, which I will try to spell out, for the mind-body problem. But first I will say a few words about the relation between Darwinism and Popper’s theory of knowledge. Against my contention that Darwin’s ideas do not seem to have had a serious impact on Popper before about 1960 it might be objected that their influence had shown itself already in Logik der Forschung (1934); for Popper there declared that the aim of the

3 I am here drawing on the Popper papers.