An illusionist theory of consciousness claims that phenomenal consciousness does not actually exist—it is an illusion created by introspective distortion of brain processes. This article compares illusionism with identity theory, a form of physicalism from over fifty years ago that identifies mental states with physical states. Both theories are physicalist, deny special mental properties, and argue that belief in the mental arises from error. However, they differ: illusionism rejects a neutral notion of experience, redefines the mind-body problem, denies a real referent for phenomenal language, and offers more epistemologically influential arguments. The author concludes that while illusionism draws on identity theory, it is fundamentally novel and independent.
The classic conception of qualia—as intrinsic, ineffable, and subjective features of experience—cannot serve as a neutral starting point for theories of phenomenal consciousness. A watered-down "diet" version of qualia is often assumed to fill this role, but the article argues that this diet notion has no distinctive content. Once qualia are stripped of intrinsicality, ineffability, and subjectivity, no phenomenal residue remains. Therefore, if classic qualia realism is rejected, what needs explaining are only "zero" qualia: dispositions to judge that experiences have classic qualia. Diet qualia should be abandoned.
The article argues that the watered-down "diet" conception of qualia—stripped of intrinsic, ineffable, and subjective properties—has no distinctive content and cannot serve as a neutral explanandum for theories of phenomenal consciousness. If classic qualia realism is rejected, there is no phenomenal residue left to explain; only "zero" qualia remain, which are dispositions to judge that experiences have classic qualia. The author concludes that diet qualia should be quined, or eliminated, as a useful concept.