Abstract

Whether defended or criticized, Darwinism is generally considered a scientific theory. However, Popper contests this point. According to him, Darwinism (defined as the explanation of evolution by natural selection) is less a scientific theory than a metaphysical research program: a theoretical framework that has a heuristic function for science, but that does not fulfill the necessary condition for any science, namely testability. In terms of deconstructing Darwinism, Popper’s position is therefore interesting. It raises the question of the scientificity of Darwinism. More generally, it raises the question of the scientificity of the debate on the mechanisms of evolution: what type(s) of argument(s) does this debate bring into play? Can this debate be reduced to an opposition between a scientifically founded theory (Darwinism) and other theories of evolution that are purely philosophical, or even ideological? First, I analyze Popper’s position. According to him, Darwinism is rationally defensible, but difficult to test because it is not capable of making precise and sufficiently specific predictions. Darwinism is therefore more metaphysical than scientific, even if it has a heuristic function for science. Moreover, Popper proposes an improvement of Darwinism by asserting that it must give a more important place to the activity of organisms in evolution. In a second step, I discuss Popper’s position, taking into account the criticisms that this position has generated. As regards the non-testability of Darwinism, it appears that the tests proposed in the literature do not meet the defects pointed out by Popper. On the metaphysical character of Darwinism, I discuss Popper’s assertion on two levels: on the possibility of a clear demarcation between science and non-science, and on the value of the demarcation criterion proposed by Popper. Finally, on the improvement of Darwinism, I attempt to underline the originality of the Popperian proposal.