To make inferences as to the object from the sort of experience which we naturally call a "perception," we must know physics and the physiology of the sense-organs, and we must have exhaustive information about what is in the intervening space between us and the object. ... In the case of distant objects, like the sun, this is not difficult to see. But it is equally true of what we touch and smell and. taste, since our "perception" of such things is due to elaborate processes which travel along the nerves to the brain.
Source: Religion and Science, 1935, chapt. 5:
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