This thesis is a critical examination of the direct realist theory of perception. A
common-sense analysis of perception is defended against arguments which are widely
believed to rule out the direct realist's notion of a direct contact with external physical
reality. I argue that a common-sense version of direct realism can adequately account
for hallucinations, perceptual relativity, perceptual illusions, severe time-lags and the
causal processes involved in perception. The views of prominent twentieth-century
direct realists are critically examined, with the intention of identifying constraints on any
plausible direct realist theory of perception. I maintain that there are representationalist
tensions in the work of leading twentieth-century direct realists, and that a principal
source of these representationalist tensions is their adherence to the common element
thesis, the notion that hallucinations and genuine perceptions are the very same
experience. Appealing to recent cognitive science experiments on the imagination, I
defend a disjunctivist analysis of experience, one which holds that hallucinations and
genuine perceptions involve fundamentally different experience-types, rather than
sharing a common, world-independent experience. The analysis which emerges is nonepistemic in its denial that perceptual experiences are essentially cognitive. A nonintentional and non-propositional species of perceptual representational content is
proposed, one which recognises qualia of perceptual experience. Recent attempts by
direct realists to apply Russellian acquaintance to the direct perception of external
physical reality are rejected as inconsistent with the central ideas in Russellian
acquaintance. Traditional Humean difficulties about the elusiveness of the self in
introspection, and the question of how we could know we perceive if we are never
acquainted with the self, are addressed by appeal to Russell's largely overlooked notion
of learning to be acquainted with objects
