find an instance of inquiry into the cause of more definite and limited phenomena, which seems much more to suggest the true spirit of physical inquiry. "We have one recorded by Herodotus, which is the more remarkable from being so nearly alone. It is in reference to the fact which he had observed about the flooding of the Nile—that it was flooded for one hundred days, beginning with the summer solstice; and that from that time it diminished, and was during the winter months very low. He tells us that he made pressing inquiries about the cause of it from many of the Egyptians, but that he found no satisfaction, and apparently little interest in the matter. Three different theories on the subject that had been propounded by the Greeks he examines in detail and confutes; and finally he states a theory of his own. And yet even in this instance of scientific inquiry he commits the usual fault of the Greeks—he does not pursue far enough the investigation of the facts of the case, and the absence of the facts he tries to make up for by exhaustive arguments on words used in describing the phenomena.
Strange as it may seem at a first glance, it is a very similar trouble that we find with the reasoning of Aristotle. It seems strange, I say, because we are accustomed to associate with Aristotle just those things which would seem to indicate a scientific temper, and to give promise of great results: 1. Extensive accumulation of facts. Many of those works of Aristotle which remain to us are vast treasuries of facts collected from almost every field of Nature, and we have reason for thinking that he made other wonderful collections of facts which have not come down to us. His work has been a standing marvel to all time. 2. Extraordinary powers of reasoning. 3. The fact that he asserted in the strongest terms the need of building up the whole superstructure of knowledge on experience. And yet throughout his works, side by side with the evidences of profound knowledge and profound speculation, there are repeated instances of reasonings which are not only unsound, but altogether puerile—e.g., in the beginning of his treatise on the heavens he proves the world to be perfect by reasoning of the following kind: "The bodies of which the world is composed are solids, and therefore have three dimensions. Now, three is the most perfect number; it is the first of numbers, for of one we do not speak as a number; of two we say both; but three is the first number of which we say all; moreover, it has a beginning, a middle, and an end." That is a fair instance of his scientific incompetency. He has the facts, he is able to reason, but he does not reason according to the facts; he loses sight of them and builds up great arguments on words and names. To give one more example: "He is endeavoring to explain the fact that when the sun's light passes through a hole, whatever
