How might consciousness have evolved? Unfortunately for the prospects of providing a convincing answer to this question, there is no agreed account of what consciousness is. So any attempt at an answer will have to fragment along a number of different lines of enquiry. More fortunately, perhaps, there is general agreement that a number of distinct notions of consciousness need to be distinguished from one another; and there is also broad agreement as to which of these is particularly problematic – namely phenomenal consciousness, or the kind of conscious mental state which it is like something to have, which has a distinctive subjective feel or phenomenology (henceforward referred to as p-consciousness). I shall survey the prospects for an evolutionary explanation of p-consciousness, on a variety of competing accounts of its nature. My goal is to use evolutionary considerations to adjudicate between some of those accounts.

Drawing distinctions

One of the real advances made in recent years has been in distinguishing different notions of consciousness (see particularly: Rosenthal, 1986; Dretske, 1993; Block, 1995; Lycan, 1996). Not everyone agrees on quite which distinctions need to be drawn; but all are at least agreed that we should distinguish creature consciousness from mental-state consciousness. It is one thing to say of an individual person or organism that it is conscious (either in general or of something in particular); it is quite another thing to say of one of the mental states of a creature that it is conscious.