Abstract

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