Appletons' Popular Science Monthly, July 1899

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Established by Edward L. Youmans

APPLETONS' POPULAR SCIENCE MONTHLY

EDITED BY WILLIAM JAY YOUMANS

VOL. LV

MAY TO OCTOBER, 1899

NEW YORK D. APPLETON AND COMPANY 1899

COPYRIGHT, 1899, BY D. APPLETON AND COMPANY.

[Illustration: WILLIAM KEITH BROOKS.]

APPLETONS' POPULAR SCIENCE MONTHLY.

JULY, 1899.

SCIENTIFIC METHOD AND ITS APPLICATION TO THE BIBLE.

BY THE REV. DAVID SPRAGUE, B. D.

"Trained and organized common sense" is Professor Huxley's definition of science. There is probably no better.

The popular mind persists in thinking that there is a wide difference between science and knowledge in general. Yes, there is a wide difference, but it is just the difference that there is between a trained and organized _body_ of men for the accomplishing of some great work, and a _crowd_ of men unorganized and undisciplined. What unscientific knowledge has accomplished may be roughly seen in the condition of savage races to-day; while the changes wrought by knowledge trained and organized, in enlarging the sum of knowledge, in extending men's power of perception, and in increasing the facilities not merely for living, but for living well, are changes in comparison with which all others recorded in history are trifling.

It will be profitable for us, in order to get a clearer idea of scientific method, to trace as briefly as possible the history of science and the development of the scientific idea.

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. Two processes must be carried out in order to yield any scientific result: facts must be patiently accumulated, and the mind must set its reasoning powers to work on them. It was in the first of these that the Greeks were wanting. They did not realize the need of endless patience in learning the details of Nature's way of working. They wished to take in all of Nature with one tremendous sweep of thought. They did a little investigating and a great deal of reasoning. Occasionally, however, we 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 be the form of the hole, the bright image, if formed at any considerable distance from the hole, is circular. This, of course, is easily seen to be a necessary consequence of the circular figure of the sun, if we conceive light to be diffused from the luminary by means of straight rays proceeding from every point. But Aristotle attempts to explain the fact by saying that the sun's light has a circular nature which it always tends to manifest. He employs the vague and loose conception of a circular _quality_ instead of the distinct conception of rays" (Whewell).

It is a kind of reasoning which may be applied with great show of success to everything, but which really proves nothing.

And so, as a matter of fact, Aristotle did not leave one single scientific generalization of value to succeeding ages.

Did not the Greeks then do anything in the way of physical science that was to stand? Yes, there was a little work that was exact, and therefore lasting. Archimedes established the fundamental principle on the one hand of the lever, on the other of pressure in fluids--that is to say, laid the stable foundation of the sciences of statics and hydrostatics. Euclid developed, if he did not discover, the law of the reflection of light. Pythagoras discovered, and his followers developed, some of the fundamental principles of harmonics. Greater than any of the others in genuine scientific work was Hipparchus, who, with many erroneous theories, yet really laid the permanent foundation of the science of astronomy. Only one more name need be mentioned among the ancients--that of Ptolemy, who seemed possessed of a genuinely scientific spirit. He accomplished little original work, made no broad generalization (what is known as the Ptolemaic system was in reality the system of Hipparchus), but more than any other of the ancients he is the type of the true scientist in these respects--the accuracy of his observations, the thoroughness of his work at every point, and the really great additions that he made to science in the way of verifying, correcting, and extending the theory he received. He lived in the early part of the second century A. D.

And the next name to attract our notice is that of Copernicus, more than twelve hundred years later. What is the meaning of that lapse of time? After such noble foundations had been laid, was there no great scientific work built thereon in all those centuries? Absolutely none. It will be well for us to think for a moment of what were the reasons for that barrenness, for the same causes are more or less at work at all times to hinder the growth of science and the extension of scientific method.

1. And what strikes us most forcibly at the outset is a lack of the sense of the importance of physical science. Through most of that period Christianity dominated the best thought of Europe, and the tremendous practical problems that confronted the Church for a long time threw everything else into the shade; for a long time, I said, during the early part of this period in especial, when the Church in general seemed to realize its responsibility to win the whole world to its Master, and every individual coming into the Church was made to feel that the Church's work was above everything else in the world. The importance of an exhaustive knowledge of the facts of Nature seemed trifling when compared with questions of character and future life, and making the world feel the power of Christ. Eusebius only expressed the thought of much of his age when he said, speaking of those who pursued the study of physical science, "It is not through ignorance of the things admired by them, but through contempt of their useless labor, that we think little of these matters, turning our souls to the exercise of better things." And with that deliberate turning away from such subjects there would come of necessity that indistinctness of ideas about natural things which is fatal to all scientific investigation. Witness these words of Lactantius: "To search for the causes of natural things; to inquire whether the sun be as large as he seems; whether the moon is convex or concave; whether the stars are fixed in the sky or float freely in the air; of what size and of what material are the heavens, whether they be at rest or in motion; what is the magnitude of the earth, on what foundations it is suspended and balanced--to dispute and conjecture on such matters is just as if we chose to discuss what we think of a city in a remote country, of which we never heard but the name." As Whewell, from whom these last two quotations are taken, says, "It is impossible to express more forcibly that absence of any definite notions on physical subjects which led to this tone of thought."

2. Contributing, without doubt, largely to that indistinctness of ideas, and to the low value put upon physical science, was the mysticism common to the early and the mediæval Church, and to the world at large for many hundred years--the mysticism, that is to say, the habit of assigning supernatural agencies to the various phenomena of Nature, and of regarding them as subject to the vicissitudes of arbitrary will rather than as following out the workings of a consistent orderly plan. There is no need of any attempt to show how fatal such a spirit is to science, nor how that spirit seemed for a long while to dominate the world. "It changed physical science to magic; astronomy to astrology; the study of the composition of bodies to alchemy; and even mathematics was changed till it became the contemplation of the spiritual relations of number and figure." That the Church was not, as has been often charged, responsible for this spiritualizing temper of the age is apparent to any one familiar with the development of Greek philosophy and with the history of the superstitions of the Roman Empire. Nevertheless, it is also true that that temper has been increased in the past and is fostered to-day by the undue emphasis which the Church has placed upon the miraculous character of early Christianity.

3. We notice in the history of the thought of this period, both in the Church and in the world at large, a disposition rather to examine, criticise, and comment upon the work of others, than to do investigating and thinking of one's own. That such a spirit should be found in the Church is not to be wondered at, for the authority of Christ and his apostles would seem to leave no room for originality of thinking on religious subjects, and the sacred Scriptures would give abundant scope for the exercise of the highest learning and of intellectual penetration in interpreting. But the same tendency is noticed outside of the Church, as the great schools of interpreters of Aristotle and of Plato, and the large volumes of abstracts and compilations from preceding writers, bear witness. But when vast learning and ability are expended, rather on such labors than on investigation into the secrets of Nature, science does not thrive.

4. And once again we observe the gradually increasing dogmatic tendency of the Church, the claim to be the repository of all knowledge, the stifling of thought, and of investigation into what might lead men away from the truth and the "faith once delivered to the saints."

It seemed best to give in detail these four evident reasons for the barrenness of science during those centuries, because, as I said, the same things to-day, though with decreasing force, interfere with the progress of science and the extension of scientific method. I shall refer to them again a little further on.

The great revival of four centuries ago in art, in learning, in religion, reached also to science. At last the spell of ignorance, of unreasoning prejudice, of offensive dogmatism, and of vague mysticism, that had held the world for so long, was broken. The new life of science was feeble at first, and remained long in its swaddling clothes. It was about the middle of the sixteenth century that Copernicus gave his great work to the world; then no great work again for nearly one hundred years, when Kepler, Galileo, and Stevinus arise. But the century has not been an idle one. Everywhere men have been awakening to the new light, have begun to think freely and fearlessly; are no longer deterred by the cry of magic or the prohibition of church dignitaries from investigating into Nature for themselves. And so, when in the seventeenth century those mighty ones appeared, thoughtful people in great numbers were found to welcome the new truths; and at almost the same time Descartes by his essay on Scientific Method, and Bacon by the Novum Organum, were able to give an impetus to scientific investigation such as the world had never felt before.

The history of the progress of science from that time to this is too complex to receive any treatment in a paper of this character. How it has been throughout a record of successive triumphs; how gradually one department after another of Nature's workings has been mastered and reduced to orderly system; how all systems have been themselves reduced to one, harmonious and complete, in the magnificent generalization of evolution; how all the time not only has the sum of knowledge been steadily augmented, but the power of acquiring knowledge marvelously enlarged--all of that we know. That which has accomplished such results is science, and the process employed has been scientific method. We are in a position now to have a fairly intelligent idea of it. Look at it and see.

"Scientific method" is not, of course, a technical expression, as are induction, deduction, etc. Yet it means something very definite. It is that method of dealing with phenomena which reason declares and experience has shown to insure the greatest accuracy in results. There are in the complete process four necessary steps: 1. Observation of facts. 2. Comparison and classification, or generalization. 3. Deduction. 4. Verification.

We can see these steps alike in the simplest scientific attempt of our remote ancestors, and in the work of a Newton or a Darwin.

To use an illustration of the former suggested by the book of Leviticus. In very early times it was noticed that animals that had both the characteristics of being cloven-hoofed and of chewing the cud were good for food. A new animal is discovered having those characteristics. It is argued from the general principle laid down that this new animal is good for food, and the matter is verified by experiment. There are the four distinct steps: observation of the facts, drawing a principle from the comparison of the facts, deducing as to the particular case, verifying. The result is, of course, not only a classifying of the particular case, but also the extension of the principle. So with the generalization of the law of gravitation. Numberless facts were observed with the greatest care; from them the principle was generalized; from that again deductions were made as to particular cases; and the results were verified. But though the steps of the process are the same in both instances, yet what a vast difference between them! Take the first step, the observation of facts. All that the thought of the earlier age could do was to note a few striking resemblances and differences among the animals that roamed the neighboring forests. What could be done in the later age, ay, what the scientific temper of the age demanded, was the most rigidly careful examination of multitudes of facts; examination by a trained mind and with all the improved appliances which science and art had given to the world, and then submitted to the searching scrutiny of other trained minds, with like appliances. Or take the last step, verification. In one case it meant finding the effect upon the taste and upon the health. In the other, what it meant may be judged from the account we have of one of Newton's investigations. In applying his hypothesis of gravitation (it was only a hypothesis then) to the motion of the moon, there was a very slight divergence, about two feet a minute, between the time of the revolution of the moon in its orbit, as he calculated it and as he observed it. He was not satisfied until, _eighteen years after_, on account of an improvement made in the method of taking observations, he was able to obtain what he regarded as a verification.