The Greek word phantasia is usually translated "imagination." However, in Greek thought the word always retains a connection with the verb phainomai, "I appear." It can be used to refer both to the psychological capacity to receive, interpret, and even produce appearances and to those appearances themselves.

Plato has little to say about phantasia as such, although in Sophist 264a he describes it as "a blend of perception and judgement (doxa)." Elsewhere, in Timaeus 70eff., in a strange passage that locates parts of the soul in particular parts of the body, he describes the liver as functioning like a mirror that reflects images coming from the rational part of the soul, suggesting a link between imagination, dreams, and inspired prophecy.

Aristotle gives phantasia a specific place in his psychology, between perception and thought. In De anima 3.3 he offers an account of phantasia that includes mental images, dreams, and...