Journal of the Royal Society of Western Australia, 92: 461–464, 2009 Philosophical perspectives on Evolutionary Theory A Tapper Centre for Applied Ethics & Philosophy, Curtin University of Technology, Bentley, WA [email protected] Manuscript received December 2009; accepted February 2010 Abstract Discussion of Darwinian evolutionary theory by philosophers has gone through a number of historical phases, from indifference (in the first hundred years), to criticism (in the 1960s and 70s), to enthusiasm and expansionism (since about 1980). This paper documents these phases and speculates about what, philosophically speaking, underlies them. It concludes with some comments on the present state of the evolutionary debate, where rapid and important changes within evolutionary theory may be passing by unnoticed by philosophers. Keywords: Darwinism, evolutionary theory, philosophy of biology; evolution. Introduction author. Biologists such as Richard Dawkins, Stephen Jay Gould, Steve Jones and Simon Conway Morris are Darwin once said that he had no aptitude for prominent. So also are historians of science, such as Peter philosophy: “My power to follow a long and purely Bowler, Janet Browne, Adrian Desmond and James R. abstract train of thought is very limited; I should, Moore. Equally likely, however, one might be introduced moreover, never have succeeded with metaphysics or to evolutionary theory by a philosopher of biology, for mathematics” (Darwin 1958). This was not false modesty; example Michael Ruse, David Hull or Kim Sterelny. (For it was the simple truth. Nevertheless, he was a great introductions to the philosophy of biology, see Lennox synthesiser of facts and theories, and he was very 2004; Sloan 2005; Griffiths 2008; other recent examples thoughtful about scientific methods (he especially valued include Brandon 1996; Hull & Ruse 1998; Sterelny & Sir John Herschel’s A Preliminary Discourse on the Study of Griffiths 1999; Hull 2001; Sterelny 2001; Pigliucci & Kaplan Natural Philosophy; see Gildenhuys 2004), so he was 2006; Hull & Ruse 2007; Rosenberg & McShea 2008.) somewhat akin to a philosopher. One of his outstanding attributes was his willingness to put forward My subject in this paper is the relation between prominently the main objections to his theory of Darwinian evolutionary theory and the discipline of evolution. Three objections stood out in 1859: philosophy. I will divide the story of this relationship, much condensed and inevitably simplified, into four • There seemed to be a mismatch between the parts. (Grene & Depew 2004 provides a grand survey of gradualism supposed by the theory and the the history of biological thought; see also Grene 1986.) discontinuities of the fossil record. • There seemed to be a disconcerting lack of transitional species in the fossil record and in Indifference living biology. For about one hundred years after the Origin the • Many organisms and many of their organs seemed leading philosophers of Britain, America, Germany and too perfectly adapted to their environments or too France – the leading countries in the field – showed perfectly suited to their functions to have come almost no interest in Darwin or Darwinism. They simply about from the haphazard processes of mutation ignored the subject altogether. They largely ignored and natural selection. biology itself. This was not because they were Darwin thought that these objections could be intellectually insular. The leading philosophers, men answered, or would be answered in time. The other great such as Frege, Russell, Moore, Wittgenstein, Husserl, absence from his theory was a coherent genetics, but Heidegger, Carnap and Quine, almost all had interests there was no scientific genetics before Mendel, so Darwin outside philosophy, but those interests were in logic, and his followers were whistling in the dark on that mathematics, physics, perception, language and ethics. matter. As things turned out, the neo-Darwinian They were also often reacting against the synthesizing synthesis of the 1930s supplied a form of genetics evolutionism – a very non-Darwinian evolutionism – of friendly to Darwinian theory. (For an analytical summary 19th century Hegelian idealists. None of them saw of contemporary Darwinian evolutionary theory, see Darwin’s evolutionism as an antidote to Hegel’s Gregory 2009). metaphysical evolutionism. But more probably the main reason why the philosophers were uninterested in In more recent times, evolutionary theory has been Darwinian theory was that they did not regard biology expounded to non-specialist readers by various kinds of as a leading science. Of course a few philosophers were interested in biology, but they were not Darwinian in © Royal Society of Western Australia 2009 outlook. They were the vitalists, of whom Hans Driesch 461 Journal of the Royal Society of Western Australia, 92(4), December 2009 is the best-known example. But none of the leading what extent Popper’s argument was taken seriously philosophers took vitalism at all seriously. amongst biologists (Hull 1999 suggests it was not), but it Nor were the philosophers interested in theology, least made an impact amongst philosophers, who set out to of all in creationist theology, as a potential world-view. show that fitness could be identified separately from To this day, philosophers almost universally disdain survival. The first generation of professional philosophers creationism and the theory of intelligent design. In this, of biology, including David Hull, Michael Ruse, Michael they are the descendants of David Hume and Immanuel Ghiselin, and Elliott Sober, were all defenders of Kant. Darwinism, defending it in part against the objection raised by Popper. This was a central topic of discussion It should also be said that none of the philosophers amongst such philosophers in the 1960s and 70s. The end held any enthusiasm for the ugly side of the Darwinian result was no doubt a victory for Darwinism. (See Sober movement – its espousing of radical individualism and, 1984 and the essays in Sober 1994; more recently, chapter far worse, of eugenicist authoritarianism. Eugenicism one of Pigliucci and Kaplan 2006). Popper had few was popular amongst many biologists but not at all supporters, and he retracted his key argument in 1978 amongst philosophers. (Popper 1978; see also Popper 1976 and Hull 1999; Hull points out various ways in which Darwin exhibited his theory as falsifiable). Criticism With the molecular biology revolution of the 1950s, Enthusiasm and expansionism the status of biology as a science changed dramatically, and this might have led to an upgrading of its prestige Having weathered this storm, Darwinism’s reputation amongst the philosophers. However, at first quite the amongst philosophers went rather rapidly from being opposite happened. Darwinian evolutionism came under clouded by Popper’s objection to being a paragon of good attack. The assault was led by one man, Karl Popper, but science and a paradigm that should be applied even since he was widely regarded as the world’s leading outside biology. This third stage has been dominant since philosopher of science, this was no small confrontation. about 1980. We can call this the period of Darwinian By Popper’s time, the Darwinians had put together a enthusiasm, perhaps even of expansionism. The formidable system. Darwin’s “descent with movement to expand Darwinism has been carried out by modification” acting through the mechanism of natural many thinkers. From within biology, E.O. Wilson led the selection, now working in tandem with Mendelian charge, but many psychologists, social scientists and genetics, had become the established framework for even philosophers have joined in the battle (Wilson 1975). much of the discipline of biology. Then the breakthrough The disciplines to be colonised were mainly psychology into the molecular domain by Watson, Crick and many and the social sciences, but gradually the expansion has others showed that biology could be integrated with come to include philosophy itself. Perhaps the key figure chemistry and presumably with physics. There seemed amongst philosophers has been Daniel Dennett. To to be no longer any good reason for not taking biology explain this movement it may help to see how Dennett seriously as a great science. arrived at the odd position of being a trumpet-blower for Popper, however, saw Darwinism as a pseudo- what he called “Darwin’s dangerous idea” (Dennett 1995; science, or at best as a “metaphysical research program”. for reviews see Orr 1996, and Gould 1997). In his words, “To say that a species now living is adapted In the 1960s it came to be fairly widely agreed that to its environment is, in fact, almost tautological. … philosophy had failed in one crucial area. It had failed to Adaptation or fitness is defined by modern evolutionists give any plausible account of the nature of the mind, as survival value, and can be measured by actual success even though the question had been central to philosophy in survival: there is hardly any possibility of testing a since Descartes in the 17th century and even though theory as feeble as this. And yet [he adds], the theory is Cartesian mind–body dualism suffered from its invaluable. … Although it is metaphysical, it sheds much seemingly anti-scientific commitment to inexplicable light upon very concrete and very practical interaction between material bodies and an unknowable researches”(Popper 1974; see also Hansson 2008).Popper non-material mind-stuff that supposedly makes up the was happy to accept the “modification by mutation” half mind. To go forward philosophy would have to cut this of the Darwinian equation. What he attacked was the Gordian knot. The cutting was done by a small number “natural selection” story, which he accused of vicious of Australian and American philosophers, one of whom circularity. The problem turned on the definition of was Dennett. Henceforward it would be taken as given “fitness”. If fitness is nothing other than survivability, that the mind just is the brain. Mind–body materialism then survival of the fittest is merely the survival of those would be taken as an axiom.