Online research in philosophy

I argue that Frank Jackson's knowledge argument cannot succeed in showing that qualia are epiphenomenal. The reason for this is that there is, given the structure of the argument, an irreconcilable tension between his support for the claim that qualia are non-physical and his conclusion that they are epiphenomenal. The source of the tension is that his argument for the non-physical character of qualia is plausible only on the assumption that they have causal efficacy, while his argument for the epiphenomenal character of qualia is plausible only on the assumption that they are non-physical. Since these two arguments cannot be combined coherently, the most Jackson's argument can establish is that qualia are non-physical.

One of the strongest objections to epiphenomenalism is that it precludes any kind of knowledge of qualia, since empirical knowledge has to include a causal relationship between the respective belief and the object of knowledge. It is argued that this objection works only if the causal relationship is understood in a very specific sense (as a 'direct' causal relationship). Epiphenomenalism can, however, live well with other kinds of causal relationships ('indirect' causal relationships) or even with a reliability account of knowledge which does not invoke causation at all. Michael Pauen has argued extensively (this volume of Journal of Consciousness Studies), however, that this line of defence doesn't work because it presupposes the existence of psychophysical laws connecting qualia with physical phenomena which cannot be established under epiphenomenalist presuppositions. It is argued that Pauen's arguments lead to sceptical consequences which threaten not only interactionist alternatives to epiphenomenalism but finally his own account.

Epiphenomenalism has been criticized with several objections. It has been argued that epiphenomenalism is incompatible with the alleged causal relevance of mental states, and that it renders knowledge of our own conscious states impossible. In this article, it is demonstrated that qualia-epiphenomenalism follows from some well- founded assumptions, and that it meets the cited objections. Though not free from difficulties, it is at least superior to its main competitors, namely, physicalism and interactionism.

Hans Muller has recently attempted to show that Frank Jackson cannot assert the existence of <span class='Hi'>qualia</span> without thereby falsifying himself on the matter of such mental states being epiphenomenal with respect to the physical world. I argue that Muller misunderstands the commitments of <span class='Hi'>qualia</span> epiphenomenalism and that, as a result, his arguments against Jackson do not go through.