Reductive Explanation and the 'Explanatory Gap'

Abstract

Can phenomenal consciousness be given a reductive natural explanation? Exponents of an ‘explanatory gap’ between physical, functional and intentional facts, on the one hand, and the facts of phenomenal consciousness, on the other, argue that there are reasons of principle why phenomenal consciousness cannot be reductively explained (Jackson, 1982, 1986; Levine, 1983, 1993, 2001; McGinn, 1991; Sturgeon, 1994, 2000; Chalmers, 1996, 1999). Some of these writers claim that the existence of such a gap would warrant a belief in some form of ontological dualism (Jackson, 1982; Chalmers, 1996), whereas others argue that no such entailment holds (Levine, 1983; McGinn, 1991; Sturgeon, 1994). In the other main camp, there are people who argue that a reductive explanation of phenomenal consciousness is possible in principle (Block and Stalnaker, 1999), and yet others who claim, moreover, to have provided such an explanation in practice (Dennett, 1991; Dretske, 1995; Tye, 1995, 2000; Lycan, 1996; Carruthers, 2000.) I shall have nothing to say about the ontological issue here (see Balog, 1999, for a recent critique of dualist arguments); nor shall I have a great deal to say about the success or otherwise of the various proposed reductive explanations. My focus will be on the explanatory gap itself – more specifically, on the question whether any such principled gap exists. I shall argue that it does not. The debate will revolve around the nature and demands of reductive explanation in general.