and space, and determine their position with regard to each other. But certain original forces will always remain over; there will always remain as an insoluble residuum a content of phenomena which cannot be referred to their form, and thus cannot be explained from something else in accordance with the principle of sufficient reason. For in everything in nature there is something of which no ground can ever be assigned, of which no explanation is possible, and no ulterior cause is to be sought. This is the specific nature of its action, _i.e._, the nature of its existence, its being. Of each particular effect of the thing a cause may be certainly indicated, from which it follows that it must act just at this time and in this place; but no cause can ever be found from which it follows that a thing acts in general, and precisely in the way it does. If it has no other qualities, if it is merely a mote in a sunbeam, it yet exhibits this unfathomable something, at least as weight and impenetrability. But this, I say, is to the mote what his will is to a man; and, like the human will, it is, according to its inner nature, not subject to explanation; nay, more—it is in itself identical with this will. It is true that a motive may be given for every manifestation of will, for every act of will at a particular time and in a particular place, upon which it must necessarily follow, under the presupposition of the character of the man. But no reason can ever be given that the man has this character; that he wills at all; that, of several motives, just this one and no other, or indeed that any motive at all, moves his will. That which in the case of man is the unfathomable character which is presupposed in every explanation of his actions from motives is, in the case of every unorganised body, its definitive quality—the mode of its action, the manifestations of which are occasioned by impressions from without, while it itself, on the contrary, is determined by nothing outside itself, and thus is also inexplicable. Its particular manifestations, through which alone it becomes visible, are subordinated to the principle of sufficient reason; it itself is groundless. This was in substance rightly understood by the schoolmen, who called it _forma substantialis_. (Cf. Suarez, Disput. Metaph., disp. xv. sect. 1.)