In the philosophy of perception, Critical realism is the theory that some of our sense-data (for example, those of primary qualities) can and do accurately represent external objects, properties, and events, while other of our sense-data (for example, those of secondary qualities and perceptual illusions) do not accurately represent any external objects, properties, and events.
According to Locke and Descartes, some sense-data, namely the sense-data of secondary qualities, do not represent anything in the external world, even if they are caused by external qualities (primary qualities). Thus it is natural to adopt a theory of critical realism.
By its talk of sense-data and representation, this theory depends on or presupposes the truth of representationalism. If critical realism is correct, then representationalism would have to be a correct theory of perception.
