A DEFENSE OF THE KNOWLEDGE ARGUMENT

Abstract

Paul Churchland distinguishes two approaches to the study of mind. [On] “the top-down approach” one starts with our current understanding of what intelligent creatures do, and then asks what sort of underlying operations could possibly produce or account for such cognitive activities. In sharp contrast, [methodological materialism] starts at the opposite end of the spectrum, and is called the “bottom-up approach”. The basic idea is that cognitive activities are ultimately just activities of the nervous system; and if one wants to understand the activities of the nervous system, then the best way to gain that understanding is to examine the nervous system itself. 1 Reductive materialists take the “top-down” approach: beginning with our mental concepts, they attempt to discover physical (or functional) states or processes to which the mental can be reduced. Although eliminativists take the “bottom-up” approach, that approach need not yield eliminativism. Whether it does so depends on whether neuroscientific research reveals properties which satisfy our mental concepts. My project in this paper is to call into question the viability of the prevailing view of the phenomenal, which weds a “top-down” approach to the mind with a materialist ontology. Call this position “top-down physicalism”. I revisit the Knowledge Argument, which aims to show that there is information about the phenomenal which is not reducible to, nor even inferrable from, information about the physical. 2 Many, like David Lewis, believe that this “Hypothesis of Phenomenal Information” (or “HPI”) threatens physicalism, for it entails that there is a sphere of non-physical facts. 3 Others, such as Michael Tye, maintain that physicalism is compatible with HPI, and that the Knowledge Argument relies on illicitly applying Leibniz’s Law within an intensional context. Corresponding to these views about HPI, there are two chief strategies for blocking the Knowledge Argument: (1) analyzing the apparent possession of phenomenal information as the having of an ability, and (2) construing it