Abstract

The impact of philosophy of science on biology is slight. Evolutionary biology, however, is nowadays an exception. The status of the neo-Darwinian (synthetic) theory of evolution is seriously challenged from a methodological perspective. However, the methodology used in the relevant discussions is plainly defective. A correct application of methodology to evolutionary theory leads to the following conclusions. (a) The theory of natural selection (the core of neo-Darwinism) is unfalsifiable in a strict sense of the term. This, however, does not militate against the theory, because no scientific theory whatever is testable in this way. Under a more liberal testability criterion, the theory is surely testable. None the less, certain (not all) research programs may tend to make the theory untestable in practice. (b) It has often been argued that the tautologous character of the principle of natural selection, allegedly the focus of evolutionary theory, makes the theory untestable through circular reasoning. Actually, the principle is only a tautology if fitness is wrongly defined in terms of actual survival. But even then circular reasoning need not ensue. (c) Evolutionary principles do not permit, without additional information, the derivation of statements about evolutionary events concerning particular species or populations. If this were a reason to criticize the theory (as has been argued in the literature), any other scientific theory would be inadequate by the same token.