Physicalist replies to Jackson's knowledge argument

One enduring question in philosophy is the metaphysical issue of whether reality fundamentally consists of physical facts only, generally the view of physicalism, or of some non-physical facts as well, generally the view of non-physicalism. Given that plausible candidates of such non-physical facts are the so-called phenomenal facts, referring to the facts of our conscious experiences, the question has been raised, specifically in the philosophy of mind, in terms of whether phenomenal facts are physical as well. Accordingly, physicalists claim that they are while non-physicalists claim otherwise. Now one celebrated argument against physicalism is Frank Jackson’s knowledge argument, which demonstrates, through a powerful thought experiment, that knowledge of phenomenal facts cannot be inferred from knowledge of physical facts. This allegedly rejects physicalism which necessarily entails the thesis that if the fundamental facts of reality are physical then all other kinds of facts, including the phenomenal ones, can be derived from these physical facts. In gist, Jackson’s knowledge argument claims that an epistemic gap exists; and this epistemic gap necessarily entails an ontological gap. Physicalists reply to this argument in a variety of ways, which this dissertation, in general, critically examines. In particular, however, this study aims to reinforce two of these physicalist replies, namely the ability hypothesis and the phenomenal concept strategy, by defending them from the objections raised by non-physicalists. These two replies constitute a formidable two-tier physicalist defense against Jackson’s knowledge argument. The ability hypothesis, as the first tier of defense, shows that there are good reasons to reject the epistemic gap assumed in the knowledge argument; while the phenomenal concept strategy, as the second tier of defense, shows that even if the assumed epistemic gap is granted, there are good reasons to reject the inference from this gap to an ontological gap. On the whole, this study shows that physicalism, through the ability hypothesis and phenomenal concept strategy, has responded well to the challenge of Jackson’s knowledge argument.