I undertook this revision of the Science of Logic, ofwhich the first volume is hereby being published, in full consciousness not only of the difficulty of its subjectmatter and of its exposition besides, but equally of the imperfection from which its treatment in the first edition suffers. As earnestly as I have striven after many years of further occupation with this science to remedy this imperfection, I still feel that I have cause enough to appeal to the reader's indulgence.One title to such appeal in the first instance maywell be based on the circumstance that for the most part only external material was available for its content in the earlier metaphysics and logic. Although the practice of these disciplines had been universal and customary, in the case of logic down to our own time, its interest in their speculative side has been just as universally and customarily restricted. It is the same material which is repeated over and over again, whether it is thinned out to the point of trivial superficiality, or whether the ancient ballast is freshly trotted out and dragged to new lengths, so that, through these habitually only mechanical efforts, no gain could be had for the philosophical content. To display the realm of thought philosophically, that is, in its own immanent activity or, what is the same, in its necessary development, had to be, therefore, a new undertaking, one that had to be started right from the beginning. Nevertheless, the received material, the known thought-forms, must be regarded as an extremely important fund, even a necessary condition, a presupposition to be gratefully acknowledged even though what it offers here and there is only a bare thread, the dead bones of a skeleton thrown together in a disorderly heap.

The forms of thought are first set out and stored in human language, and one can hardly be reminded often enough nowadays that thought is what differentiates the human being from the beast. In everything that the human being has interiorized, in everything that in some way or other has become for him a representation, in whatever he has made his own, there has language penetrated, and everything that he transforms into language and expresses in it contains a category, whether concealed, mixed, or well defined.