Externalism is a philosophical view that emphasizes the role of external factors in shaping knowledge, beliefs, and mental states. According to externalists, the context and environment surrounding an individual significantly influence their understanding and justification of knowledge. This perspective contrasts with internalism, which focuses on internal states and processes. In the realm of epistemology, externalism suggests that factors outside an individual's mind, such as social interactions or the reliability of information sources, can determine whether a belief is justified. Prominent figures in this debate include Hilary Putnam and Alvin Goldman, who have contributed to the development of externalist theories.