THE PRE-CRITICAL WRITINGS. 327 in the satire Dreams of a Ghost -seer explained by the Dreams of Metaphysics, 1766, which pours out its ingenious sarcasm impartially on spiritualism and on the assumed knowledge of the suprasensible. Here Kant is already clearly conscious of his new problem, a theory of the limits of human reason, conscious also that the attack on this prob- lem is to be begun by a discussion of the question of space. This second question had been for many years a fre- quent subject of his reflections;* and it was this part of the general critical problem that first received definitive solution. In the Latin dissertation On the Form a7id Princi- ples of the Sensible and Intelligible World, 1770, which con- cludes the pre-critical period, and which was written on the occasion of his assumption of his chair as ordinary profes- sor, the critique of sensibility, the new theory of space and time, is set forth in approximately the same form as in the Critique of Pure Reason, while the critique of the under- standing and of reason, the theory of the categories and the Ideas and of the sphere of their validity, required for its completion the intellectual labor of several more years. For this essay, De Mundi Sensibilis atque Intelligibilis Forma et Principiis, leaves unchallenged the possibility of a knowledge of things in themselves and of God, thus show- ing that its author has abandoned the skepticism main- tained in the Dreams of a Ghost-seer, and has turned anew to dogmatic rationalism, whose final overthrow required another swing in the direction of skeptical empiricism. In regard to the progress of this latter phase of opinion, the letters to M. Herz arc almost the only, though not very valuable, source of information. The Critique of Pure Reasott appeared in 1781, much later than Kant had hoped when he began a work on " The Limits of Sensibility and Reason," and a second, altered edition in I787.t After the Prolegomena to every Future
- New Theory of Motion and Rest, 1758; On the First Ground of the Distinc-
tion of Positions in Space, 1768 ; besides several of the works mentioned above.
There has been much discussion and much has been written concerning the
relation of the two editions. In opposition to Schopenhauer and Kuno Fischer it must be maintained that the alterations in the second edition consist in giving greater prominence to realistic elements, which in the first edition remained in the background, though present even there. I
