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A. J. Ayer on the Argument from Illusion

Published online by Cambridge University Press:  01 January 2020

P. L. McKee*
Affiliation:
Colorado State University

Extract

In his paper “Has Austin Refuted the Sense-Datum Theory?” A. J. Ayer contends that the argument from illusion calls attention to perspectival distortion, perceptual misidentification and elusive perceptual belief only in order to establish the possibility of perceptual error. Pointing to our occasional perceptual failures reminds us that perceptual error is always logically possible—that any particular perceptual belief to the effect that one is perceiving a physical surface could be mistaken. This in turn is thought by Ayer to show that the ordinary belief that we perceive physical surfaces requires qualification—along lines urged by sense-datum philosophers—to the effect that even in those situations properly described for non-philosophical purposes as perceptions of physical surfaces it cannot be physical surfaces that are literally present to one's senses. Ayer believes that this can be established, for any given case, by the possibility of perceptual error alone.

Type
Research Article
Copyright
Copyright © The Authors 1973

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References

1 First published in Synthese, Vol. 17 (1967). Republished in Metaphysics and Common Sense (San Francisco: Freeman, Cooper & Company, 1970). References are to the latter.

2 See Barcan, Ruth C.The Identity of Individuals in a Strict Functional Calculus,” The Journal of Symbolic Logic, Vol. 12 (1947), p. 15.CrossRefGoogle Scholar See also Hughes, G. E. and Cresswell, M. L. An Introduction to Modal Logic (London: Methuen & Co., 1968), p. 190.Google Scholar For a parallel formulation and use of this point, see Fitch, F. B.The Problem of the Morning Star and the Evening Star” in Copi, Irving I. and Gould, James M. Contemporary Readings in Logical Theory (New York, 1967), p. 272.Google Scholar