August 1971
A Note on The Muddle of Extrasensory Perception
J. J. Gibson, Cornell University
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The controversy and confusion over extrasensory perception, I suggest, has at its roots an implicit unrecognized ambiguity in the meaning of the term sensory. One meaning of sensory perception is perception based on stimulation of receptors.Another menaing is perception based on the having sensations. One can postulate that there is no perception without stimulation of some sort, or one can postulate that there is no perception without conscious sensations, the data of perception. The verb to sense can mean to detect something or it can mean to have an elementary experience on the basis of which something is detected. Extrasensory perception, therefore, can mean perception without the pickup of stimulus information or it can mean perception without any awareness of stimulation. The first, it seems to me, is quite impossible. The second, I believe, happens all the time.
The theory of information-based perception (Gibson, 1966) asserts that perception without sensation is possible but that perception without stimulation is impossible. The theory of sensation-based perception assumes that stimulation and sensation are the same thing and that both are necessary for perception. The first theory assumes that stimulation is necessary for perception because it normally carries information about the environment; the second theory assumes that it is necessary because it arouses sensation.
Whether or not there is sensationless perception is an empirical question. Evidence like that of Michotte strongly suggests that there is. Whether or not there is informationless perception is a philosophical question involving problems of mind and matter, the belief in innate ideas, the possibility that all minds are one substance, and the like.
Once we distinguish between the two meanings of the verb to sense we can accept the empirical possibility of valid intuitions or above-chance guesses without being involved in epistemological mysteries. When we fail to distinguish the two meanings we are up to our necks in mystery.
The doctrine that all knowledge is acquired by way of “the senses” and in no other way can mean that all knowledge came through the channels of sense and the correlated modalities of sensation. In this form, the doctrine is hard to defend. But it can also mean that all knowledge is acquired by means of the active senses, the perceptual systems (Gibson, 1966). The first form of the doctrine is an associationalempiricism implying the enrichment of bare sensations by the mind. The second form of the doctrine is a discriminational empiricism implying the differentiation of stimulus information by the observer.