Ernest Sosa is an American philosopher known for his work in epistemology, the study of knowledge. He has contributed significantly to discussions about the nature of knowledge, belief, and justification. Sosa is often associated with the concept of "virtue epistemology," which emphasizes the role of intellectual virtues in acquiring knowledge. Born in 1940, Sosa has held academic positions at various institutions, including Brown University. He has authored several influential books and articles, such as "Knowledge in Perspective" and "A Virtue Epistemology." His ideas have shaped contemporary debates in philosophy, particularly regarding the relationship between knowledge and belief.