The great man of science, unless he is also a philosopher (I think of such names as Newton and Gauss, Linnæus and Darwin, Copernicus and Galileo), deserves the title of genius as little as the man of action. Men of science are not universal; they deal only with a branch or branches of knowledge. This is not due, as is sometimes said, merely to the extreme modern specialisation that makes it impossible to master everything. Even in the nineteenth and twentieth centuries there are still amongst the learned men individuals with a knowledge as many-sided as that of Aristotle or Leibnitz; the names of von Humboldt and William Wundt at once come to my mind. The absence of genius comes from something much more deeply seated in the men of science, and in science itself, from a cause which I shall explain in the eighth chapter. Probably some one may be disposed to argue that if even the most distinguished men of science have not a knowledge so universal as that of the philosopher, there are some who stand on the outermost fringes of philosophy, and to whom it is yet difficult to deny the word genius. I think of such men as Fichte, Schleiermacher, Carlyle, and Nietzsche. Which of the merely scientific has felt in himself an unconditioned comprehension of all men and of all things, or even the capacity to verify any single thing in his mind and by his mind? On the contrary, has not the whole history of the science of the last thousand years been directed against this? This is the reason why men of science are necessarily one-sided. No man of science, unless he is also a philosopher, however eminent his achievements, has that continuous unforgetting life that the genius exhibits, and this is because of his want of universality. Finally, it is to be observed that the investigations of the scientific are always in definite relation to the knowledge of their day. The scientific man takes possession of a definite store of experimental or observed knowledge, increases or alters it more or less, and then hands it on. And much will be taken away from his achievements, much will silently disappear; his treatises may make a brave show in the libraries, but they cease to be actively alive. On the other hand, we can ascribe to the work of the great philosopher, as to that of the great artist, an imperishable, unchangeable presentation of the world, not disappearing with time, and which, because it was the expression of a great mind, will always find a school of men to adhere to it. There still exist disciples of Plato and Aristotle, of Spinoza and Berkeley and Bruno, but there are now none who denote themselves as followers of Galileo or Helmholtz, of Ptolemy or Copernicus. It is a misuse of terms, due to erroneous ideas, to speak of the “classics” of science or of pedagogy in the sense that we speak of the classics of philosophy and art.