In the thesis it is argued that the account of experience that fits best with our ordinary concept of perception involves a commitment to disjunctivism - the view that the experience a subject has when he perceives the world is not one that the subject could have if he were hallucinating. A critique of the most promising non-disjunctive account of experience is provided. This theory of perception involves an acceptance of an intentional theory of experience together with the causal theory of perception. According to the intentional theory, an experience is a psychological state with an intentional content that represents the world as being a certain way. The causal theory of perception is the theory that it is part of our ordinary concept of perception that in order for a subject to perceive the world the subject's experience must be appropriately caused by the objects he is perceiving. It is argued that in order to avoid a commitment to disjunctivism, the intentional theorist needs to accept the generality thesis - the thesis that the content of successful perceptual experience is an existentially quantified one that is not to be specified by using terms that refer to the particulars of which one is aware in having the experience. An argument is provided to establish that the account of experience that best accommodates all that is involved in our concept of perception involves a rejection of the generality thesis. It is argued that if one rejects the generality thesis, as one should, then the arguments that are used to support the causal theory of perception are undermined. The epistemological significance of rejecting the generality thesis is also explored. Finally, objections to disjunctivism are considered and rejected.