This paper develops a view of the content of perceptual states that reflects the cognitive significance those states have for the subject. Perhaps the most important datum for such a theory is the intuition that experiences are ‘transparent’, an intuition promoted by philosophers as diverse as Sartre and Dretske. This paper distinguishes several different transparency theses, and considers which ones are truly supported by the phenomenological data. It is argued that the only thesis supported by the data is much weaker than those typically considered in the literature, and has no obvious implications for the existence of sensory intermediaries. It does, however, have implications for the content of perceptual experience. It is argued that combining the first personal project with the transparency intuition yields an error theory of perception. The counterintuitive implications of this error theory are mitigated, however, by an account of perceptual beliefs which allows for them to be true even if the perceptual states are non-veridical.