Unfortunately, philosophers of science usually regard scientific realism and scientific anti-realism as monistic doctrines. The assumption is that there is one goal of all scientific inference - finding propositions that are true, or finding propositions that are predictively accurate. In fact, there are multiple goals. Sometimes realism is the right interpretation of a scientific problem, while at other times instrumentalism is.

Evolutionary biologists often appeal to parsimony when they seek to explain why organisms "match" with respect to a given trait. For example, why do almost all the organisms that are alive today on our planet use the same genetic code? If they share a common ancestor, the code could have evolved just once and then been inherited from the most recent common ancestor that present organisms share. On the other hand, if organisms in different species share no common ancestors, the code must have evolved repeatedly.

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 more evolutionary theory gets called an atheistic theory, the greater the risk that it will lose its place in public school biology courses in the United States. If the theory is thought of in this way, one should not be surprised if a judge at some point decides that teaching evolutionary theory violates the Constitutional principle of neutrality with respect to religion.

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.

Deism claims that God creates the universe and the laws of nature and then is hands-off, with everything that subsequently happens in nature being due to natural processes.

One influential philosophical position about the use of probability in science holds that probabilities are objective only if they are based on micro-physics; all other probabilities should be interpreted subjectively, as merely revealing our ignorance about physical details. I have argued against this position, contending that the objectivity of micro-physical probabilities entails the objectivity of macro-probabilities.