While continuing to think deeply and write tumultuously on topics in metaphysics, philosophy of mind, philosophy of language, action theory, ethics, metaphilosophy,…, Hector CastaŇeda has found time over the years to compose a significant body of material on knowledge and epistemic justification.¹ It culminates (to date) in his imposing paper (1980), in which he presents "a tentative analysis of knowledge that p" (p. 226), embedded within a more general "contribution to basic epistemology and to the philosophy of cognitive language" (p. 193). His approach departs in several useful ways from current orthodoxies in epistemology. In our study of his theory of knowing we shall concentrate on this paper, adverting to others where appropriate.²