Abstract

A mutation alters the hemoglobin in some members of a species of antelope, and as a result the members fare better at high altitudes than their conspecifics do; so high-altitude foraging areas become open to them that are closed to their conspecifics; they thrive, reproduce at a greater rate, and the gene for altered hemoglobin spreads further through the gene pool of the species. That sounds like a classic example (owed to Karen Neander, 1995) of a causal chain traced by evolutionary biology. But a view now nearly universal among philosophers maintains that such biological causation is always shadowed, perhaps even rivaled, by causation on a different level.1 That the subgroup of antelopes forages in areas closed to the conspecifics is a state of affairs embodied or realized, notes this view, in certain movements and state changes done by certain physical microparticles—untold billions of microparticles and movements, but a finite and determinate (more on this below) collection nevertheless. That the subgroup reproduces at a greater rate is likewise realized by a huge collection of microparticle movements, a different collection. And the microparticle happenings comprised in the first collection are causally responsible, strictly in accordance with the laws of microphysics, for the microparticle happenings in the second. Biological causation is always shadowed, perhaps even rivaled, by causation on the level of microphysics. The view I mean is general: any case of causing uncovered by any of the special sciences can be recaptured at the level of microphysics. This view is I think what most philosophers mean by “physicalism”; in any case, “physicalism” is the label I shall use. Physicalism comes in two forms. Modest physicalism holds that any causal transaction reported by the special sciences can be retraced by microphysics.2 Hegemonic physicalism holds that retracing such a transaction at the level of..