Self-consciousness constitutes an insurmountable obstacle to functionalism. Either the standard functional definitions of mental relations wrongly require the contents of self-consciousness to be propositions involving “realizations” rather than mental properties and relations themselves. Or else these definitions are circular. The only way to save functional definitions is to expunge the standard functionalist requirement that mental properties be second-order and to accept that they are first-order. But even the resulting “ideological” functionalism, which aims only at conceptual clarification, fails unless it incorporates the thesis that the mental properties are fully “natural” universals. Accordingly, mental properties are sui generis: first-order, nonphysical, natural universals.