Page:Aristotelous peri psuxes.djvu/157



CH. III.] to each sense is true, or it involves the smallest amount of error; but when, in the second place, such objects are perceived in their accidents, there is room for fallacy; when for instance, something is said to be white, there is no fallacy, but when that object is particularised and said to be this or that, the perception may be fallacious. There is, in the third place, liability to error in our perception of common properties, and sequences in the accidents referrible to particular bodies—accidents, I mean, such as motion and magnitude, which are referrible to all bodies, and from which there is peculiar liability to error through the senses. But the motion produced by the act of sensation will differ from the sensation derived from these three modes of sensation—the first, while sensation is yet present, must be true; but the others, whether sensation be present or not, may be fallacious, and more especially, when the objects causative of sensation may have been withdrawn. If, then, imagination alone fulfil all the conditions indicated, and if it be all that has been said, it may be defined as motion produced by sensation in action. And since vision is a sense above all others, imagination has derived its appellation from light, because without light there is no vision; and owing to its being an abiding faculty and like sensations, animals perform many of their actions through it. Some animals are so influenced from being irrational; and others, as man, from having