Perception is our main source of epistemic access to the outside world. Perception and Basic Beliefs addresses two central questions in epistemology: which beliefs are epistemologically basic (i.e., noninferentially justified) and where does perception end and inferential cognition begin. Jack Lyons offers a highly externalist theory, arguing that what makes a belief a basic belief or a perceptual belief is determined by the nature of the cognitive system, or module, that produced the beliefs. On this view, the sensory experiences that typically accompany perceptual beliefs play no indispensable role in the justification of these beliefs, and one can have perceptual beliefs-justified perceptual beliefs-even in the absence of any sensory experiences whatsoever. Lyons develops a general theory of basic beliefs and argues that perceptual beliefs are a species of basic beliefs. This results from the fact that perceptual modules are a special type of basic belief-producing modules. Importantly, some beliefs are not the outputs of this class of cognitive module; these beliefs are therefore non-basic, thus requiring inferential support from other beliefs for their justification. This last point is used to defend a reliabilist epistemology against an important class of traditional objections (where the agent uses a reliable process that she doesn't know to be reliable).

Perception and Basic Beliefs brings together an important treatment of these major epistemological topics and provides a positive solution to the traditional problem of the external world.