"...Philosophy, whenever after a period of decay it enters upon a period of revival again, always begins with an extraordinary and exaggerated expectation. At such a time it lives in the hope that by means of continued serious investigation it will solve the riddle of the world. But always after this young over-excitement the old disillusionment enters in. So far from decreasing, the problems increase as the study proceeds. What seemed to be self-evident proves to be a new mystery, and the end of all knowledge is then again the sad and sometimes despairing confession that man walks about on the earth in riddles, and that life and destiny are mysteries."