Alex Rosenberg

Philosophical Darwinism is a species of naturalism. Among philosophers, naturalism is widely treated as the view that contemporary scientific theory is the source of solutions to philosophical problems. Thus, naturalists look to the theory of natural selection as the primary source in coming to solve philosophical problems raised by human affairs. For it combines more strongly than any other theory relevance to human affairs and scientific warrant. Other theories, especially in physics and chemistry, are more strongly confirmed, especially because their more precise predictions can be tested in real time. But these theories have little to tell us about human conduct and institutions. On the other hand, actual and possible theories, in the social and behavioral sciences, may in the future have more tell us about humanity than Darwinian theory, but these theories do not as yet have anything like the degree of confirmation of Darwin’s theory. Since Darwinism has important consequences for human affairs, the naturalist must look to Darwin’s theory, above all others, in the search for philosophical understanding.

Reductionism is a metaphysical thesis, a claim about explanations, and a research program. The metaphysical thesis reductionists advance (and antireductionists accept) is that all facts, including all biological facts, are fixed by the physical and chemical facts; there are no non-physical events, states, or processes, and so biological events, states and processes are “nothing but” physical ones. The research program can be framed as a methodological prescription which follows from the claim about explanations. Antireductionism does not dispute reductionism’s metaphysical claim, but rejects the explanatory claim and so the methodological moral. To a first approximation what reductionists and antireductionists disagree about is whether explanations in functional biology can be or need to be explained by or completed or perhaps replaced by explanations in terms of molecular biology.i And this disagreement over the adequacy of explanations in functional biology drives a significant methodological disagreement with consequence for the research program of biology.