Darwin repeatedly used the hypothesis of common ancestry as a platform on which to build his various ideas about testing hypotheses concerning natural selection. He also argued that adaptive similarities provide little or no evidence for common ancestry. Although this second claim needs to be fine-tuned, Darwin was right that ample evidence for common ancestry can exist even if none of the characteristics we observe were caused to evolve by natural selection.

Darwin and his successors have railed against the fallacy of confusing the current utility of a trait with the reason the trait evolved. For example, Darwin argued that skull sutures in mammals did not evolve because they facilitate live birth; the sutures were in place well before live birth evolved. Checking the chronological order in which different traits evolved in a lineage is one way to test an adaptive hypothesis; the fact of common ancestry is what makes that checking possible.

I have spent a lot of time arguing that the theory of group selection is not the stupid, pernicious doctrine that many biologists once claimed it to be. The theory is not just conceptually coherent; there are adaptations out there in nature (like reduced virulence in some viruses) that evolved because there was group selection.

I think that the existence of Beethoven is remarkable, but I do not bristle at the suggestion that this event had a low probability given the initial state of the universe.

Scientists often seek predictively accurate models, rather than models that are true.

The indispensability argument seeks to assimilate the epistemology of metaphysical statements to the epistemology of statements that are obviously empirical. I think it fails to achieve this goal. The argument does not refute the Carnapian thesis that scientific theories and metaphysical claims differ epistemologically - observations can provide evidence for the former, but not for the latter.

The upshot is that most philosophers of biology now hold that biological properties supervene on physical properties (where supervenience is taken to include some kind of "in virtue of" relation), and that fitness and other biological properties are not identical with physical properties.