Evolutionary Explanation and Consciousness

If there is a received orthodoxy in contemporary philosophy of mind and cognitive science, it is that all features of the mind, including meaning, action, and consciousness, can and perhaps must be naturalized (i.e., accommodated within the framework of the world of nature as understood by the natural sciences). At the same time, just about everyone working in philosophy of mind has realized for at least a decade that there are substantial problems with this enterprise of naturalizing the mind, in that there are features of the mind that do not seem to lend themselves to naturalistic explanation: in particular, meaning, consciousness, and free will. For naturalists (who comprise the majority of the field at the moment), this is seen as an urgent problem: they feel that we must naturalize the mind, and yet it looks as though we do not know how to do so. Oddly, even many of the writers who have forcefully argued that the mental cannot be reduced to the physical, or cannot be explained in evolutionary terms, sti ll call themselves "naturalists," even when they have no concrete naturalization of the mind to offer. A few other anti-naturalists and I, on the other hand, have tried to argue that the problems the naturalist faces are abiding and principled problems, and not merely a symptom of a current lack of development of psychology or neuroscience. In this article for the special issue, I shall attempt to do three things. First, I shall attempt to describe the current situation in philosophy of mind and cognitive science with respect to one special facet of the mind: consciousness. I shall try to explain, in a very abbreviated form, the historical factors that have led to the popularity of reductionist forms of naturalism, and then summarize several influential arguments to the effect that consciousness cannot be reduced to neuroscience or physics. I shall then differentiate two very different strands of this conversation: one which is about explanation (i.e., physical science cannot explain consciousness), and anoth er which is about metaphysics (i.e., physical facts are not enough to determine facts about consciousness). Finally, I shall explain why think that naturalizers of the mind can look for no solace from evolutionary explanation if--as appears to be the case--attempts at reductive explanation of the mind in terms of physics or neuroscience should continue to fail: in brief, because evolutionary explanation depends upon the fulfillment of a promissory note which only reductive explanation could make good on. It is thus only in the final section of this article that I shall approach the uniting theme of the special issue. However, to understand the status of evolutionary explanation in philosophy of mind, it is in my opinion necessary to see where it fits within a broader framework of naturalizing the mind. NATURALIZING CONSCIOUSNESS AND THE EXPLANATORY GAP Over the past twenty years, a large proportion of the work done in philosophy of mind has been framed in terms of the enterprise of naturalizing the mind, or accommodating it within the framework of the world of nature as understood by the natural sciences. On the surface, at least, naturalism appears to be very close to a consensus view in philosophy of mind. If you read books written in philosophy of mind in the last twenty years, you will find a growing trend towards describing one's own project as an attempt to "naturalize" the mind, and indeed to cast one's discussion within the assumption that what everyone is looking for is a "naturalistic" theory of the mind. One might even view naturalism as the prevailing trend of the entire twentieth century. For example, Jerry Fodor writes, "Here, then are the ground rules. I want a naturalized theory of meaning; a theory that articulates, in nonsemantic and nonintentional terms, sufficient conditions for one bit of the world to be about (to express, represent, or be true of) another bit" (1987, p. …