Perception and knowledge
- Key People:
- Aristotle
- Plato
- John Locke
- St. Augustine
- Immanuel Kant
- Related Topics:
- innate idea
- tabula rasa
- sensationalism
- coherentism
- foundationalism
- On the Web:
- Yale University - CampusPress - What Is Epistemology? (Mar. 27, 2025)
The epistemological interests of sense-data theory.
The technical term sense-data is sometimes explained by means of examples. If one is hallucinating and sees pink rats, one is having a certain visual sensation of rats of a certain colour, though there are no real rats present. The sensation is what is called a “sense-datum.” The image one sees with one’s eyes closed after looking fixedly at a bright light (an afterimage) is another example. Even in cases of normal anomalies. The aim of those thinkers was to give a phenomenalism.
mind. It is especially the second of those principles that distinguishes realists from phenomenalists.
Realists believe that an Foundations of Empirical Knowledge (1940), Ayer called the difficulty “the egocentric predicament.” When a person looks at what he thinks is a physical object, such as a chair, what he is directly apprehending is a sense-datum, a certain visual appearance. But such an appearance seems to be private to that person; it seems to be something mental and not publicly accessible. What, then, justifies the individual’s Moore and his followers, continued to accept the existence of sense-data, but, unlike traditional realists, they held that, rather than mental entities, sense-data might be physical parts of the surface of the perceived object itself. Other direct realists, such as the perceptual psychologist optics and opaque surface, cones, the bipolar cells, and the ganglion cells of the real world corresponds to their perceptions. They are still appearance after all. It thus seems that neither version of realism satisfactorily solves the problem with which it began.