Abstract

Philosophers in the tradition of Berkeley say that the first step in gaining knowledge from perception is to report or describe one's perceptual data, or that which one sees ‘immediately'. Further, perceptual data are existing things of some sort, and always are exactly as they appear to be since, as H. H. Price says, “in the sphere of the given … what seems, is”. However, these two claims about perceptual data are sometimes incompatible, as the following case shows. Suppose a man looking at a speckled hen reports that it has many speckles but is not able to report the exact number of speckles it has. If above is correct, the man's perceptual datum, as opposed to the physical hen itself which he sees—according to Berkeleians—in a merely indirect sense, would have to be indeterminate in character. Yet we assume that everything which exists ) is and has to be completely determinate. A person's knowledge is indeterminate if he knows that the planet Mars has either two or three satellites and doesn't know which. But Mars itself at any moment has to have some definite number of satellites.