its _sole reason for existence_ is adequately summed up in saying that it exists, not for its own sake, but merely _to vivify and sensitize the organism_. Consequently, the brute soul, though inextended and incorporeal, belongs, not to the spiritual, but to the material, order of things. Is the human soul equally material in nature, or does it belong to the spiritual category of being? The state of the question has long since been formulated for us by Aristotle: “A further difficulty,” he says, “arises as to whether all attributes of the soul are also shared by that which has the soul or whether any of them are peculiar to the soul itself: a problem which it is imperative, and yet by no means easy, to solve. It would appear that in most cases it neither acts nor is acted upon apart from the body: as, _e.g._, in anger, courage, desire, and sensation in general. Thought, if anything, would seem to be peculiar to the soul. Yet if thought is a sort of imagination, or something not independent of imagination, it will follow that not even thought is independent of the body. If, then, there be any functions or affections of the soul that are peculiar to it, it will be possible for the soul to be separated from the body: if, on the other hand, there is nothing peculiar to it, the soul will not be capable of separate existence.” (“Peri Psyches,” Bk. I, chap. I, 9.) We shall see that the human soul has certain operations which it discharges independently of the intrinsic coägency of the organism, _e.g._, abstract thought (not to be confounded with the concrete imagery of the imagination) and deliberate volition (to be distinguished from the urge of the sensual appetite). Hence, over and above the organic functions, which it discharges in conjunction with the material organism, the human soul has superorganic functions, of which it is itself, in its own right, the exclusive agent and recipient. In other words, it exists _for its own sake_ and not merely to perfect the body.