A History of Science — Volume 5

by Henry Smith Williams; Edward Huntington Williams

When, further, we reflect that with all our capacity to measure and estimate this strange force of gravitation we, after all, know absolutely nothing as to its real nature; that we cannot even imagine how one portion of matter can act on another across an infinite abysm (or, for that matter, across the smallest space), we see at once that our most elementary scientific studies bring us into the presence of inscrutable mysteries. In whatever direction we turn this view is but emphasized. Electricity, magnetism, the hypothetical ether, the inscrutable forces manifested everywhere in the biological field—all these are, as regard their ultimate nature, altogether mysterious.

In a word, the student of nature is dealing everywhere with the wonderful, the incomprehensible. Yet all the manifestations that he observes are found to repeat themselves in certain unvarying sequences. Certain applications of energy will produce certain movements of matter. We may not know the nature of the so-called cause, but we learn to measure the result, and in other allied cases we learn to reason back or infer the cause from observation of results. The latter indeed is the essence of scientific inquiry. When certain series of phenomena have been classified together as obviously occurring under the domination of the same or similar causes, we speak of having determined a law of nature. For example, the fact that any body in motion tends to go on at the same rate of speed in a direct line forever, expresses such a law. The fact that the gravitation pull is directly as the mass and inversely as the square of the distance of the bodies it involves, expresses another such law. The fact that the planetary bodies of the solar system revolve in elliptical orbits under the joint influence of the two laws just named, expresses yet another law. In a word, then, these so-called "laws" are nothing more than convenient formulae to express the classification of observed facts.

INDUCTIVE VERSUS DEDUCTIVE REASONING

The ancient thinkers indulged constantly in what we now speak of as deductive reasoning. They gave heed to what we term metaphysical preconceptions as to laws governing natural phenomena. The Greeks, for example, conceived that the circle is the perfect body, and that the universe is perfect; therefore, sun and moon must be perfect spheres or disks, and all the orbits of the heavenly bodies must be exactly circular. We have seen that this metaphysical conception, dominating the world for many centuries, exerted a constantly hampering influence upon the progress of science. There were numerous other instances of the same retarding influence of deductive reasoning. Modern science tries to cast aside all such preconceptions. It does not always quite succeed, but it makes a strenuous effort to draw conclusions logically from observed phenomena instead of trying to force observations into harmony with a preconeived idea. Herein lies the essential difference between the primitive method and the perfected modern method. Neither the one nor the other is intended to transcend the bounds of the natural. That is to say, both are concerned with the sequence of actual events, with the observation of actual phenomena; but the modern observer has the almost infinite advantage of being able to draw upon an immense store of careful and accurate observations. A knowledge of the mistakes of his predecessors has taught him the value of caution in interpreting phenomena that seem to fall outside the range of such laws of nature as experience has seemed to demonstrate. Again and again the old metaphysical laws have been forced aside by observation; as, for example, when Kepler showed that the planetary orbits are not circular, and Galileo's telescope proved that the spot-bearing sun cannot be a perfect body in the old Aristotelian sense.

New means of observation have from time to time opened up new fields, yet with all the extensions of our knowledge we come, paradoxically enough, to realize but the more fully the limitations of that knowledge. We seem scarcely nearer to-day to a true understanding of the real nature of the "forces" whose operation we see manifested about us than were our most primitive ancestors. But in one great essential we have surely progressed. We have learned that the one true school is the school of experience; that metaphysical causes are of absolutely no consequence unless they can gain support through tangible observations. Even so late as the beginning of the nineteenth century, the great thinker, Hegel, retaining essentially the Greek cast of thought, could make the metaphysical declaration that, since seven planets were known, and since seven is the perfect number, it would be futile to search for other planets. But even as he made this declaration another planet was found. It would be safe to say that no thinker of the present day would challenge defeat in quite the Aristotelian or Hegelian manner; but, on the other hand, it is equally little open to doubt that, in matters slightly less susceptible of tangible demonstration, metaphysical conceptions still hold sway; and as regards the average minds of our time, it is perhaps not an unfair estimate to say they surely have not advanced a jot beyond the Aristotelian stand-point. Untrained through actual experience in any field of inductive science, they remain easy victims of metaphysical reasoning. Indeed, since the conditions of civilization throw a protecting influence about us, and make the civilized man less amenable to results of illogical action than was the barbarian, it may almost be questioned whether the average person of to-day is the equal, as a scientific reasoner, of the average man of the Stone Age.

A few of the more tangible superstitions of primitive man have been banished from even the popular mind by the clear demonstration of science, but a host remains. I venture to question whether, if the test could be made in the case of ten thousand average persons throughout Christendom, it would not be found that a majority of these persons entertain more utterly mistaken metaphysical ideas regarding natural phenomena than they do truly scientific conceptions. We pride ourselves on the enlightenment of our age, but our pride is largely based on an illusion. Mankind at large is still in the dark age. The historian of the remote future will see no radical distinction between the superstitions of the thirteenth century and the superstitions of the nineteenth century. But he will probably admit that a greater change took place in the world of thought between the year 1859 and the close of the nineteenth century than had occurred in the lapse of two thousand years before If this estimate be correct, it is indeed a privilege to be living in this generation, for we are on the eve of great things, and beyond question the revolution that is going on about us denotes the triumph of science and its inductive method. Just in proportion as we get away from the old metaphysical preconceptions, substituting for them the new inductive method, just in that proportion do we progress. The essence of the new method is to have no preconceptions as to the bounds of nature; to regard no phenomenon, no sequence of phenomena, as impossible; but, on the other hand, to accept no alleged law, no theory, no hypothesis, that has not the warrant of observed phenomena in its favor.

The great error of the untrained mind of the primitive man was that he did not know the value of scientific evidence. He made wide leaps from observed phenomena to imagined causes, quite overlooking the proximal causes that were near to hand. The untrained observer of to-day makes the same mistake; hence the continued prevalence of those superstitious misconceptions which primitive man foisted upon our race. But each new generation of to-day is coming upon the field better trained in at least the rudiments of scientific method than the preceding generation, and this is perhaps the most hopeful feature of present-day education. Some day every one will understand that there is no valid distinction between the natural and the supernatural; in fact, that no such thing as a supernatural phenomenon, in the present-day acceptance of the word, can conceivably exist.

All conceivable manifestations of nature are natural, nor can we doubt that all are reducible to law—that is to say, that they can be classified and reduced to systems. But the scientific imagination, as already pointed out, must admit that any and every scientific law of our present epoch may be negatived in some future epoch. It is always possible, also, that a seeming law of to-day may be proved false to-morrow, which is another way of saying that man's classification improves from generation to generation. For a "natural law," let it be repeated, is not nature's method, but man's interpretation of that method.

LOGICAL INDUCTION VERSUS HASTY GENERALIZATION

A great difficulty is found in the fact that men are forever making generalizations—that is, formulating laws too hastily. A few phenomena are observed and at once the hypothesis-constructing mind makes a guess as to the proximal causes of these phenomena. The guess, once formulated and accepted, has a certain influence in prejudicing the minds of future observers; indeed, where the phenomena involve obscure principles the true explanation of which is long deferred, a false generalization may impress itself upon mankind with such force as to remain a stumbling-block for an indefinite period. Thus the Ptolemaic conception of the universe dominated the thought of Europe for a thousand years, and could not be substituted by the true theory without a fierce struggle; and, to cite an even more striking illustration, the early generalizations of primitive man which explain numberless phenomena of nature as due to an influence of unseen anthropomorphic beings remain to this day one of the most powerful influences that affect our race—an influence from which we shall never shake ourselves altogether free until the average man—and particularly the average woman—learns to be a good observer and a logical reasoner.