The validity of functional explanations as they are commonly used in psychology has recently come under attack. Kim’s supervenience argument purports to prove that higher-level generalizations have no causal powers of their own, and hence are explanatorily irrelevant. In a nutshell, the supervenience argument forces us to either embrace epiphenomenalism of higher-level properties, or accept Kim’s specific brand of reductionism. However, with the current emphasis on mechanistic explanations, the literature on explanation in psychology has undergone some drastic changes. It could be argued, therefore, that Kim’s argument targets an outdated concept of functional explanations. In any case, these developments warrant a reassessment of the implications of his argument, which is the purpose of the present paper. First, we argue that the metaphysics behind the supervenience argument is incompatible with that of mechanisms. Second, we argue that Kim’s proposed brand of reductionism does not accurately describe the explanatory practices of cognitive science.