Philosophical theories of mental content include internalism, externalism, representationalism and intentionality. It repudiates the notions of universal truth, epistemological foundationalism, representationalism, and epistemic objectivity. Rockmore is a strong critic of representationalism in epistemology. On the other hand, weak representationalism claims only that phenomenal character supervenes on intentional content. Apparitional experiences appear "prima facie" more compatible with the philosophical theory of representationalism. Most representationalists endorse an unrestricted version of representationalism. A semantic difficulty may arise when considering reference in representationalism. Strong representationalism can be further broken down into restricted and unrestricted versions. Strong representationalism attempts to reduce phenomenal character to intentional content. Representationalism is one of the key assumptions of cognitivism in psychology. Thus representationalism remains an incomplete description of perception.