Abstract

This chapter defends the knowledge argument’s third main step: the inference from the modal gap to a corresponding ontological gap. It argues that physicalism requires that the physical grounds the mental, which in turn requires that the physical necessitates the mental. Then it defends that argument against objections due to Zhong, Montero, and Brown. According to Zhong, ontological dependence is like causal dependence: such dependence relations can obtain in the absence of necessitation. In response, the chapter argues that Zhong’s analogy is inapt. It then turns to hypothetical scenarios in which, it is claimed, ontological dependence obtains without necessitation. Zhong, Montero, and Montero and Brown each make versions of that claim. However, each version rests on mistakes. Zhong’s version commits an equivocation fallacy. Montero and Brown fail to account for the fact that physicalism is a version of monism—and they make unwarranted assumptions about the modal relationship between fundamental physics and higher-level sciences.