Volume I Part 1 (1/2)
A History of Science.
Volume 1.
by Henry Smith Williams.
BOOK I
Should the story that is about to be unfolded be found to lack interest, the writers must stand convicted of unpardonable lack of art. Nothing but dulness in the telling could mar the story, for in itself it is the record of the growth of those ideas that have made our race and its civilization what they are; of ideas instinct with human interest, vital with meaning for our race; fundamental in their influence on human development; part and parcel of the mechanism of human thought on the one hand, and of practical civilization on the other. Such a phrase as ”fundamental principles” may seem at first thought a hard saying, but the idea it implies is less repellent than the phrase itself, for the fundamental principles in question are so closely linked with the present interests of every one of us that they lie within the grasp of every average man and woman--nay, of every well-developed boy and girl.
These principles are not merely the stepping-stones to culture, the prerequisites of knowledge--they are, in themselves, an essential part of the knowledge of every cultivated person.
It is our task, not merely to show what these principles are, but to point out how they have been discovered by our predecessors. We shall trace the growth of these ideas from their first vague beginnings. We shall see how vagueness of thought gave way to precision; how a general truth, once grasped and formulated, was found to be a stepping-stone to other truths. We shall see that there are no isolated facts, no isolated principles, in nature; that each part of our story is linked by indissoluble bands with that which goes before, and with that which comes after. For the most part the discovery of this principle or that in a given sequence is no accident. Galileo and Keppler must precede Newton. Cuvier and Lyall must come before Darwin;--Which, after all, is no more than saying that in our Temple of Science, as in any other piece of architecture, the foundation must precede the superstructure.
We shall best understand our story of the growth of science if we think of each new principle as a stepping-stone which must fit into its own particular niche; and if we reflect that the entire structure of modern civilization would be different from what it is, and less perfect than it is, had not that particular stepping-stone been found and shaped and placed in position. Taken as a whole, our stepping-stones lead us up and up towards the alluring heights of an acropolis of knowledge, on which stands the Temple of Modern Science. The story of the building of this wonderful structure is in itself fascinating and beautiful.
I. PREHISTORIC SCIENCE
To speak of a prehistoric science may seem like a contradiction of terms. The word prehistoric seems to imply barbarism, while science, clearly enough, seems the outgrowth of civilization; but rightly considered, there is no contradiction. For, on the one hand, man had ceased to be a barbarian long before the beginning of what we call the historical period; and, on the other hand, science, of a kind, is no less a precursor and a cause of civilization than it is a consequent. To get this clearly in mind, we must ask ourselves: What, then, is science?
The word runs glibly enough upon the tongue of our every-day speech, but it is not often, perhaps, that they who use it habitually ask themselves just what it means. Yet the answer is not difficult. A little attention will show that science, as the word is commonly used, implies these things: first, the gathering of knowledge through observation; second, the cla.s.sification of such knowledge, and through this cla.s.sification, the elaboration of general ideas or principles. In the familiar definition of Herbert Spencer, science is organized knowledge.
Now it is patent enough, at first glance, that the veriest savage must have been an observer of the phenomena of nature. But it may not be so obvious that he must also have been a cla.s.sifier of his observations--an organizer of knowledge. Yet the more we consider the case, the more clear it will become that the two methods are too closely linked together to be dissevered. To observe outside phenomena is not more inherent in the nature of the mind than to draw inferences from these phenomena. A deer pa.s.sing through the forest scents the ground and detects a certain odor. A sequence of ideas is generated in the mind of the deer. Nothing in the deer's experience can produce that odor but a wolf; therefore the scientific inference is drawn that wolves have pa.s.sed that way. But it is a part of the deer's scientific knowledge, based on previous experience, individual and racial; that wolves are dangerous beasts, and so, combining direct observation in the present with the application of a general principle based on past experience, the deer reaches the very logical conclusion that it may wisely turn about and run in another direction. All this implies, essentially, a comprehension and use of scientific principles; and, strange as it seems to speak of a deer as possessing scientific knowledge, yet there is really no absurdity in the statement. The deer does possess scientific knowledge; knowledge differing in degree only, not in kind, from the knowledge of a Newton. Nor is the animal, within the range of its intelligence, less logical, less scientific in the application of that knowledge, than is the man. The animal that could not make accurate scientific observations of its surroundings, and deduce accurate scientific conclusions from them, would soon pay the penalty of its lack of logic.
What is true of man's precursors in the animal scale is, of course, true in a wider and fuller sense of man himself at the very lowest stage of his development. Ages before the time which the limitations of our knowledge force us to speak of as the dawn of history, man had reached a high stage of development. As a social being, he had developed all the elements of a primitive civilization. If, for convenience of cla.s.sification, we speak of his state as savage, or barbaric, we use terms which, after all, are relative, and which do not shut off our primitive ancestors from a tolerably close a.s.sociation with our own ideals. We know that, even in the Stone Age, man had learned how to domesticate animals and make them useful to him, and that he had also learned to cultivate the soil. Later on, doubtless by slow and painful stages, he attained those wonderful elements of knowledge that enabled him to smelt metals and to produce implements of bronze, and then of iron. Even in the Stone Age he was a mechanic of marvellous skill, as any one of to-day may satisfy himself by attempting to duplicate such an implement as a chipped arrow-head. And a barbarian who could fas.h.i.+on an axe or a knife of bronze had certainly gone far in his knowledge of scientific principles and their practical application. The practical application was, doubtless, the only thought that our primitive ancestor had in mind; quite probably the question as to principles that might be involved troubled him not at all. Yet, in spite of himself, he knew certain rudimentary principles of science, even though he did not 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 a.n.a.lysis, we may note in pa.s.sing, 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 const.i.tute 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 a.s.sociated 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 s.h.i.+fting of the sun and the s.h.i.+fting 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 a.s.sociated 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 a.s.sume, 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 s.h.i.+ft its relative position in the heavens, as regards the stars; that the stars themselves, on the other hand, keep a fixed relation as regards one another, with the notable exception of two or three of the most brilliant members of the galaxy, the latter being the bodies which came to be known finally as planets, or wandering stars.
The wandering propensities of such brilliant bodies as Jupiter and Venus cannot well have escaped detection. We may safely a.s.sume, however, that these anomalous motions of the moon and planets found no explanation that could be called scientific until a relatively late period.
3. Turning from the heavens to the earth, and ignoring such primitive observations as that of the distinction between land and water, we may note that there was one great scientific law which must have forced itself upon the attention of primitive man. This is the law of universal terrestrial gravitation. The word gravitation suggests the name of Newton, and it may excite surprise to hear a knowledge of gravitation ascribed to men who preceded that philosopher by, say, twenty-five or fifty thousand years. Yet the slightest consideration of the facts will make it clear that the great central law that all heavy bodies fall directly towards the earth, cannot have escaped the attention of the most primitive intelligence. The arboreal habits of our primitive ancestors gave opportunities for constant observation of the practicalities of this law. And, so soon as man had developed the mental capacity to formulate ideas, one of the earliest ideas must have been the conception, however vaguely phrased in words, that all unsupported bodies fall towards the earth. The same phenomenon being observed to operate on water-surfaces, and no alteration being observed in its operation in different portions of man's habitat, the most primitive wanderer must have come to have full faith in the universal action of the observed law of gravitation. Indeed, it is inconceivable that he can have imagined a place on the earth where this law does not operate.
On the other hand, of course, he never grasped the conception of the operation of this law beyond the close proximity of the earth. To extend the reach of gravitation out to the moon and to the stars, including within its compa.s.s every particle of matter in the universe, was the work of Newton, as we shall see in due course. Meantime we shall better understand that work if we recall that the mere local fact of terrestrial gravitation has been the familiar knowledge of all generations of men. It may further help to connect us in sympathy with our primeval ancestor if we recall that in the attempt to explain this fact of terrestrial gravitation Newton made no advance, and we of to-day are scarcely more enlightened than the man of the Stone Age. Like the man of the Stone Age, we know that an arrow shot into the sky falls back to the earth. We can calculate, as he could not do, the arc it will describe and the exact speed of its fall; but as to why it returns to earth at all, the greatest philosopher of to-day is almost as much in the dark as was the first primitive bowman that ever made the experiment.
Other physical facts going to make up an elementary science of mechanics, that were demonstratively known to prehistoric man, were such as these: the rigidity of solids and the mobility of liquids; the fact that changes of temperature transform solids to liquids and vice versa--that heat, for example, melts copper and even iron, and that cold congeals water; and the fact that friction, as ill.u.s.trated in the rubbing together of two sticks, may produce heat enough to cause a fire.
The rationale of this last experiment did not receive an explanation until about the beginning of the nineteenth century of our own era.
But the experimental fact was so well known to prehistoric man that he employed this method, as various savage tribes employ it to this day, for the altogether practical purpose of making a fire; just as he employed his practical knowledge of the mutability of solids and liquids in smelting ores, in alloying copper with tin to make bronze, and in casting this alloy in molds to make various implements and weapons.
Here, then, were the germs of an elementary science of physics.
Meanwhile such observations as that of the solution of salt in water may be considered as giving a first lesson in chemistry, but beyond such altogether rudimentary conceptions chemical knowledge could not have gone--unless, indeed, the practical observation of the effects of fire be included; nor can this well be overlooked, since scarcely another single line of practical observation had a more direct influence in promoting the progress of man towards the heights of civilization.