 This best known, though now widely rejected, form of representative realism incorporates a sense-datum theory  (see the entry on  sense-data),  which holds that every perceptual experience as of something’s being F involves the subject’s awareness of something that really is F. My having a perceptual (veridical or hallucinatory) experience as of something’s being blue requires there to be a nonphysical, inner, mental object—a sense-datum—that is blue. Sense-data are not normally taken to be true or false, any more than rocks or tables are; nonetheless, sense-data constitute the inner rocks and tables in virtue of which we perceive external rocks and tables and are in that sense the latter’s representatives. Two important features of this theory are worth highlighting: (i) that sense-data really do have the properties that external objects appear to have, and (ii) that the relation one stands in to one’s sense-data is a perceptual, or quasi-perceptual, relation: one is perceptually aware of objects due to a more fundamental awareness of one’s sense-data.