experimental sciences, and at their extreme point stands mathematics; the other series of knowledge recognizes the question, but gives no answer to it: that is the series of the speculative sciences, and at their extreme point stands metaphysics.
Ever since my early youth I had been interested in the speculative sciences, but later mathematics and the natural sciences attracted me, and so long as I did not clearly put my question, so long as the question did not of itself rise in me, insisting on an answer, I was satisfied with those fictitious answers which sciences give to the question.
In the sphere of the experimental sciences, I said to myself: “Everything develops, is differentiated, moves in the direction of complexity and perfection, and there are laws which govern this progress. You are a part of the whole. Having, in so far as it is possible, learned the whole, and having learned the law of evolution, you will learn your place in this whole, and all about yourself.” I am ashamed to confess it, there was a time when I seemed to be satisfied with that. That was the time when I myself was growing more complex and was developing. My muscles grew and became stronger, my memory was being enriched, my ability to think and comprehend was increasing, I grew and developed, and, feeling within me that growth, it was natural for me to think that that was the law of the whole world, in which I should find a solution also to the questions of my life. But the time came when my growth stopped,—I felt that I was not developing, but drying up, that my muscles were growing weaker and my teeth falling out,—and I saw that that law not only explained nothing to me, but that there never was and never could have been such a law, and that I took for a law what I found within me at a certain period of life. I was more severe toward the definition of that law; and it became clear to me that there could be no law of endless development; it became clear to me that saying that
