Trait X is fitter than trait Y in a population of organisms if those organisms have other biological traits T and live in an environment that has properties E. The theory of natural selection is filled with statements of this form.

"Tiger is a natural kind" and "Tiger is a historical particular" are incompatible with each other, and evolutionary biology provides a reason for favoring the latter over the former.

Our own species evolved under the influence of group selection, as Darwin emphasized when he discussed the evolution of altruism.

"Methodological naturalism" and "metaphysical naturalism" are terms that often surface in the continuing battle between evolutionary biology and creationism/intelligent design. The methodological thesis says that scientific theories shouldn't postulate supernatural entities; the metaphysical thesis says that no such entities exist. In this debate, God is the supernatural entity at issue; the question isn't whether science gets to talk about mathematical entities if Platonism is correct.

I think that some "interventionist theisms" are compatible with evolutionary theory. (By "intervention," I don't mean that God violates laws of nature; I mean that God affects what happens in nature in ways that are additional to the ones that deism recognizes.)

Earlier attempts to show that simpler theories always have higher prior probabilities have failed, but there is a restricted circumstance in which the claim is right.

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.