  In 201d–202d, the famous passage known as The Dream of Socrates, a two-part ontology of elements and complexes is proposed. Parallel to this ontology runs a theory of explanation that claims that to explain, to offer a logos, is to analyse complexes into their elements, i.e., those parts which cannot be further analysed. Crucially, the Dream Theory says that knowledge of O is true belief about O plus an account of O’s composition. If O is not composite, O cannot be known, but only “perceived” (202b6). When Socrates argues against the Dream Theory (202d8–206b11), it is this entailment that he focuses on.