The subject that perceives a sense-object must itself be single, and grasp this object in its totality, by one and the same power. This happens when by several organs we perceive several qualities of a single object, or when, by a single organ, we embrace a single complex object in its totality, as, for instance, a face. It is not one principle that sees the face, and another one that sees the eyes; it is the "same principle" which embraces everything at once. Doubtless we do receive a sense-impression by the eyes, and another by the ears; but both of them must end in some single principle. How, indeed, could any decision be reached about the difference of sense-impressions unless they all converged toward the same principle? The latter is like a centre, and the individual sensations are like radii which from the circumference radiate towards the centre of a circle. This central principle is essentially single. If it was divisible, and if sense-impressions were directed towards two points at a distance from each other, such as the extremities of the same line, they would either still converge towards one and the same point, as, for instance, the middle (of the line), or one part would feel one thing, and another something else. It would be absolutely as if I felt one thing, and you felt another, when placed in the presence of one and the same thing (as thought Aristotle, de Anima[53]). Facts, therefore, demonstrate that sensations centre in one and the same principle; as visible images are centred in the pupil of the eye; otherwise how could we, through the pupil, see the greatest objects? So much the more, therefore, must the sensations that centre in the (Stoic) "directing principle"[54] resemble indivisible intuitions and be perceived by an indivisible principle. If the latter possessed extension, it could, like the sense-object, be divided; each of its parts would thus perceive one of the parts of the sense-object, and nothing within us would grasp the object in its totality. The subject that perceives must then be entirely one; otherwise, how could it be divided? In that case it could not be made to coincide with the sense-object, as two equal figures superimposed on each other, because the directing principle does not have an extension equal to that of the sense-object. How then will we carry out the division? Must the subject that feels contain as many parts as there are in the sense-object? Will each part of the soul, in its turn, feel by its own parts, or will (we decide that) the parts of parts will not feel? Neither is that likely. If, on the other hand, each part feels the entire object, and if each magnitude is divisible to infinity, the result is that, for a single object, there will be an infinity of sensations in each part of the soul; and, so much the more, an infinity of images in the principle that directs us. (This, however, is the opposite of the actual state of affairs.)