The very beginning of science is beyond our ken. We can form no idea of just what stage in the intellectual development of the race witnessed the rise of training and order in men's knowledge. Long before the dawn of history there must have been some degree of orderliness in men's knowledge--some grouping of facts, and reasoning from one thing to another. Rude classification would be made, e. g., among animals, as some were found to be good for food and others not; so among herbs, as to size, form, color, use for food and medicine, poisonous qualities, etc.; so among woods, as some were better adapted than others to use as instruments of war and of the chase. Men must also, very early in their development, have noticed the changes that took place in the heavens: the sun by day, the moon and the stars by night; have grouped the stars into little clusters here and there as they seemed rudely to resemble forms of things which they knew, and as some were brighter than the rest; have begun to reckon periods of time according as position of sun and moon varied. In their observation of the heavens no other phenomenon would have attracted as much attention as an eclipse, and for a long time men would have ascribed this occasional phenomenon to the intervention of some supernatural power. In process of time, however, as their observations were made with more care and recorded, some regularity would be noticed in these, as in other phenomena of the skies; and the period of their recurrence being at last approximately known by those more learned than the rest, predictions of eclipses would be made and verified by what would seem to the multitude direct supernatural aid. Hence the earliest scientific records that have come down to us are of eclipses observed, and in time regularly predicted, by the Chaldeans; hence also the reputation that was always given to the Chaldeans of having magical power. Coming down now to the time when men first seemed to have a genuine spirit of scientific inquiry, we find it among the Greeks some five hundred years B. C. Whatever of rudely scientific work had been done before, seems to have been for practical or religious purposes. About that time, however, men began to investigate and speculate in order to find out the truth, and soon we see a class of men, known as philosophers, whose one aim was to find out, because they loved, the truth. "What they saw excited them to meditate, to conjecture, and to reason; they endeavored to account for natural events, to trace their causes, to reduce them to principles" (Whewell). They set about this, too, in no small, narrow way. They wanted to go right to the bottom of things, of everything at once, and to know the great principles, as they called them, of Nature and of life. That was the reason why the actual scientific results of Greek thought, with all its splendid powers, were so meager. Two things are the necessary conditions of science--facts, and the human power of reasoning.