The infinite divisibility of space and of matter forms the chief difficulty in the problem of the continuous. Herbart endeavors to solve it by the assumption of an intelligible space with “fixed” lines (lines formed by a definite number of points, hence finitely divisible, and not continuous). Metaphysics demands the fixed or discrete line, although common thought is incapable of conceiving it. Space is a mere form of combination in representation or for the observer, and yet it is objective, i.e., it is valid for all intelligences, and not merely for human intelligence. From his complex and unproductive endeavors to derive the appearance of continuity from discontinuous reality we hurry on to the fourth, the psychological problem, which Herbart discusses with great acuteness. He considers it the chief merit of Fichte’s Science of Knowledge that it called attention to this problem.
The concept of the ego, of whose reality we have so strong and immediate a conviction that, in the formula of asseveration, “as true as I exist,” it is made the criterion of all other certitude, labors under various contradictions. Besides the familiar difficulty, here especially sensible, of one thing with many marks, it contains other absurdities of its own. In the ego or self-consciousness subject and object are to be identical. The identity of the representing and the represented ego is a self-contradictory idea, for the law of contradiction forbids the equation of opposites, while a subject is subject only through the fact that it is not object. But, again, self-consciousness can never be realized, because it involves a regressus in infinitum. The ego is defined as that which represents itself. What is this “self”? It is, in turn, the self-knower. This new explanation contains still a further self; which once more signifies the self-knower and so on to infinity. The ego represents the representation (Vorstellen) of its representation (Vorstellen), etc. The representation (Vorstellung) of the ego, therefore, can never be actually brought to completion. (The assumption of the freedom of the will leads to an analogous regressus in infinitum, in which