• DOI:10.1068/p200001
• Corpus ID: 5521054

Putting Illusions in their Place

@article{Gregory1991PuttingII,
  title={Putting Illusions in their Place},
  author={RICHARD L. Gregory},
  journal={Perception},
  year={1991},
  volume={20},
  pages={1 - 4}
}

• R. Gregory
• Published 1 February 1991
• Education
• Perception

Putting illusions in their place We see the Natural Sciences describing, explaining, and classifying phenomena. These do not follow any clear historical sequence, for each affects and may transform the others. So whales become mammals; lightning becomes electricity; the heart becomes a pump; the brain becomes (some kind of) a computer, as explanations change appearances and force changes of classification. Much the same should apply to the Unnatural Science of illustory phenomena, which are departures from the world of the Natural Sciences. To put illusions in their place we may start with their appearances; but explanations often suggest changes of appearance-categories. Illusions that look similar or even identical may turn out to be very different. How should we set out to classify explanations of the odd phenomena of perception including the even odder phenomena of illusions? The primary difficulty is lack of generally agreed explanations, even for some familiar illusions that have been studied for over a hundred years. We also lack a general definition of 'illusion'. But at least there is almost complete agreement that there are illusions, what these are, and that they are interesting and important for understanding perception. So let's attempt to put illusions in their place with a classification of appearances sensitive to various explanations. Different authorities may assign different categories, and illusions may change categories as understanding advances; but to be useful the explanation-categories themselves should be generally acceptable, and only be changed when this is clearly seen to be necessary. By going beneath appearances, the explanation-categories will have conceptual significance with undertones (or do I mean overtones?) which may not harmonize with all theoretical accounts. There is no way of deducing useful categories. They must be posited by a daring leap of imagination. Having made such a leap we may all agree it is daring, but is it more than imagination? Does it help us to see and relate illusions more clearly? Well—let's leap—and see where we land! For take-off, we may regard perceptions as descriptions. Though perceptions are non-verbal (or pre-verbal) descriptions, we may expect kinds of errors of language to suggest categories of perceptual illusions. This assumption is our take-off for putting visual illusions in their place. The main errors of language it seems to me, and the main kinds of illusions, are: Ambiguities, Distortions, Paradoxes, and Fictions. For examples of these in language: