Sosa, Ernest (b. 1941), Cuban-born American philosopher whose publications span the field, including epistemology, metaphysics, philosophy of mind, value theory, and the history of philosophy. He is best known as a metaphysician, philosopher of mind, and especially as an epistemologist. Sosa has also contributed greatly to the profession by training over forty PhDs and through his editorial work, especially as Editor of Philosophy and Phenomenological Research (since 1983) and Noûs (since 1999). Sosa earned his PhD from the University of Pittsburgh in 1964, where he studied with Nicholas Rescher and Wilfrid Sellars. Sosa taught at Brown University from 1964 to 2007, where he worked closely with Roderick Chisholm. Upon retiring from Brown, Sosa took up a position at Rutgers University (New Brunswick). Sosa is best known for originating the contemporary research program in virtue epistemology ('The Foundations of Foundationalism,' 1980; A Virtue Epistemology, vol. 1, 2007), and for thoroughly developing and applying the distinction between animal knowledge and reflective knowledge (Knowledge in Perspective, 1991; A Virtue Epistemology, vol. 2, 2009). Sosa defines animal knowledge as 'apt belief,' which is belief that is true because formed through the exercise of an intellectual virtue or competence, which in turn is a cognitive disposition to reliably form true beliefs in normal conditions. Sosa defines reflective knowledge as 'apt belief aptly noted.' Within metaphysics, Sosa is best known for his defense of realism about the external world along with his advocacy of some 1 | 2 form of relativism ('Existential Relativity,' 1999; 'Putnam's Pragmatic Realism,' 1993): the truth-value of existence claims are relative to a context of thought or speech (relativism), but they are nevertheless true in virtue of the mind-independent arrangement of matter and form (realism). In the philosophy of mind, Sosa is best known for defending a 'Fregean' theory of reference, according to which reference to an object is fundamentally a matter of the object's uniquely satisfying a description (e.g. 'the so-and-so') rather than a matter of bearing appropriate causal relations ('Fregean Reference Defended,' 1995; 'Propositional Attitudes De Dicto and De Re,' 1970). Word count: