A History of Science, vol 1 | Page 5

formulate them.
Let us inquire what some of these principles are. Such an inquiry will, as it were, clear the ground for our structure of science. It will show the plane of knowledge on which historical investigation begins. Incidentally, perhaps, it will reveal to us unsuspected affinities between ourselves and our remote ancestor. Without attempting anything like a full analysis, we may note in passing, not merely what primitive man knew, but what he did not know; that at least a vague notion may be gained of the field for scientific research that lay open for historic man to cultivate.
It must be understood that the knowledge of primitive man, as we are about to outline it, is inferential. We cannot trace the development of these principles, much less can we say who discovered them. Some of them, as already suggested, are man's heritage from non-human ancestors. Others can only have been grasped by him after he had reached a relatively high stage of human development. But all the principles here listed must surely have been parts of our primitive ancestor's knowledge before those earliest days of Egyptian and Babylonian civilization, the records of which constitute our first introduction to the so-called historical period. Taken somewhat in the order of their probable discovery, the scientific ideas of primitive man may be roughly listed as follows:
1. Primitive man must have conceived that the earth is flat and of limitless extent. By this it is not meant to imply that he had a distinct conception of infinity, but, for that matter, it cannot be said that any one to-day has a conception of infinity that could be called definite. But, reasoning from experience and the reports of travellers, there was nothing to suggest to early man the limit of the earth. He did, indeed, find in his wanderings, that changed climatic conditions barred him from farther progress; but beyond the farthest reaches of his migrations, the seemingly flat land-surfaces and water-surfaces stretched away unbroken and, to all appearances, without end. It would require a reach of the philosophical imagination to conceive a limit to the earth, and while such imaginings may have been current in the prehistoric period, we can have no proof of them, and we may well postpone consideration of man's early dreamings as to the shape of the earth until we enter the historical epoch where we stand on firm ground.
2. Primitive man must, from a very early period, have observed that the sun gives heat and light, and that the moon and stars seem to give light only and no heat. It required but a slight extension of this observation to note that the changing phases of the seasons were associated with the seeming approach and recession of the sun. This observation, however, could not have been made until man had migrated from the tropical regions, and had reached a stage of mechanical development enabling him to live in subtropical or temperate zones. Even then it is conceivable that a long period must have elapsed before a direct causal relation was felt to exist between the shifting of the sun and the shifting of the seasons; because, as every one knows, the periods of greatest heat in summer and greatest cold in winter usually come some weeks after the time of the solstices. Yet, the fact that these extremes of temperature are associated in some way with the change of the sun's place in the heavens must, in time, have impressed itself upon even a rudimentary intelligence. It is hardly necessary to add that this is not meant to imply any definite knowledge of the real meaning of, the seeming oscillations of the sun. We shall see that, even at a relatively late period, the vaguest notions were still in vogue as to the cause of the sun's changes of position.
That the sun, moon, and stars move across the heavens must obviously have been among the earliest scientific observations. It must not be inferred, however, that this observation implied a necessary conception of the complete revolution of these bodies about the earth. It is unnecessary to speculate here as to how the primitive intelligence conceived the transfer of the sun from the western to the eastern horizon, to be effected each night, for we shall have occasion to examine some historical speculations regarding this phenomenon. We may assume, however, that the idea of the transfer of the heavenly bodies beneath the earth (whatever the conception as to the form of that body) must early have presented itself.
It required a relatively high development of the observing faculties, yet a development which man must have attained ages before the historical period, to note that the moon has a secondary motion, which leads it to shift its relative position in the heavens, as