Disjunctivism is a position in the philosophy of perception

Philosophy of perception

The philosophy of perception is concerned with the nature of perceptual experience and the status of perceptual data, in particular how they relate to beliefs about, or knowledge of, the world. Any explicit account of perception requires a commitment to one of a variety of ontological or...

 that rejects the existence of sense data

Sense data

In the philosophy of perception, the theory of sense data was a popular view held the early 20th century by philosophers such as Bertrand Russell, C. D. Broad, H. H. Price, A.J. Ayer and G.E. Moore, among others. Sense data are supposedly mind-dependent objects whose existence and properties are...

 in certain cases. The disjunction is between appearance and the reality behind the appearance "making itself perceptually manifest to someone."

Veridical perceptions and hallucination

Hallucination

A hallucination, in the broadest sense of the word, is a perception in the absence of a stimulus. In a stricter sense, hallucinations are defined as perceptions in a conscious and awake state in the absence of external stimuli which have qualities of real perception, in that they are vivid,...

s are not members of a common class of mental states or events. According to this theory, the only thing common to veridical perceptions and hallucinations is that in both cases, the subject cannot tell, via introspection, that he is not having a veridical perception. Disjunctivists claim this because they hold that in veridical perception, a subject's experience actually contains the external, mind-independent object of that perception. Further, they claim that in a hallucination there is no external object to be related to, nor are there sense-data to be a part of the perception. Thus, disjunctivism is a form of naive realism

Naïve realism

Naïve realism, also known as direct realism or common sense realism, is a philosophy of mind rooted in a common sense theory of perception that claims that the senses provide us with direct awareness of the external world...

 or direct realism.

Disjunctivism was first introduced to the contemporary literature by Michael Hinton

J. M. Hinton

John Michael Elliott Hinton was a British philosopher. He was a lecturer at the University of Oxford from 1958 and a fellow of Worcester College, Oxford from 1960. He was Cowling Visiting Professor at Carleton College in 1978-79...

, and has subsequently been associated with John McDowell

John McDowell

John Henry McDowell is a South African philosopher, formerly a fellow of University College, Oxford and now University Professor at the University of Pittsburgh. Although he has written extensively on metaphysics, epistemology, ancient philosophy, and meta-ethics, McDowell's most influential work...

. Disjunctivists often hold that an important virtue of their view is that it captures the common sense idea that perception involves a relation to objects in the world.