What is said by Kant, Fichte, Schelling, or Hegel, in one place of any of their works, is at least considerably modified, if not contradicted, in another place of the same work. It is of little consequence, how and by whose help I have arrived at the positive outcome of philosophy as here rendered. Whether it is the actual outcome or not can be judged only by the expert, and every opinion is necessarily very subjective. Under the circumstances I, as author, claim that my opinion is worth as much as any other, and the reader may therefore accept my assurance. As to the further value of that which I offer, it is a peculiarity of the subject under discussion that every reader carries it and its experiences within himself and may, without consulting any other author, at once draw his own conclusions about my views, provided he has acquired the necessary training in thought. What a traveler tells us about the interior of Africa must either be believed to the letter or verified by the accounts of other travelers. But what I say about logic will, I hope, find its corroboration in the logic of every reading brain. The theory of understanding which has become the special object of philosophy, is nothing else, and cannot be anything else, but expanded logic. Many practical rules and laws of this department are known and recognized since the time of Aristotle. But the question whether there is one world or two, a natural and unnatural, or supernatural as it is called with preference, that is the point which has given much trouble to philosophy and which will influence the health of logic so long as it is undecided. Dr. Friedrich Dittes, director of the institute of pedagogy in Vienna, has published a _School of Pedagogy_, several editions of which have appeared, in which he gives much attention to logic. Dittes is a prominent pedagogue, well known through his writings. He confines himself in his _School_ to teaching only that which is well established and accepted without a doubt. As a practical man who addresses himself mainly to teachers of primary grades, he would not place himself on the pinnacle of the outcome of philosophy, even if he could. He must confine himself to that which is well established, which is far removed from the disputes of the day. But it may here serve as a whetstone by the help of which we may give to the positive product of philosophy its latest and greatest sharpness. He writes right in the beginning of the first part: "Our ideas are as manifold as the objects to which they refer. Several things may have many or few, or at least one quality, in common. Still they may also be totally different."