THE REFORMED CHURCH REVIEW NO. 2.-APRIL, 1901. I. THE INFLUENCE OF THE NATURAL SCIENCES (SECOND PAPER.) BY R. C. SCHIEDT, PH.D. The first paper on this subject largely dealt with formal questions pertaining to the definition of the natural sciences and their relation to the so-called mental sciences which prevailed in classic antiquity as well as during the first half of the past century. I shall now discuss certain fundamental features which characterize the natural sciences to such a degree that they have revolutionized our whole mode of thinking both in method and intensity. We may, at the outset, divide the natural sciences into three groups, viz., Physics, Chemistry and Biology, not for the purpose of circumscribing their specific functions, but in order to derive from them certain general principles which may serve as elevations from which to survey the whole field. Physics and chemistry primarily deal with the lifeless, i. e., which inanimate nature, while biology on the other hand touches life, especially in Zoology and Botany, and here again more from the physiological than from the morphological aspect. However, the laws of inanimate nature, as studied in physics and chemistry, also reign in biology, but they are so complicated here, that they cannot be utilized for methodical inquiry and, therefore, a peculiarly biological system of investigation has come to prevail. I shall first of all discuss the importance which must be attached to the idea of the infinitesimal in modern science. It is true atomistic theories prevailed in classic antiquity, but only as speculations; they lacked that inward bond of proof which rests upon the phenomena of external nature. Newton was the first one who introduced in a truly scientific way the principle of the infinitesimal as the key to the comprehension of large phenomena. He created, cotemporaneously with Leibnitz, a new mathematical discipline, the infinitesimal calculus, so valuable for geometry. It is much easier to work with figures composed of straight lines than with figures composed of curves. In order to calculate a curve we divide it into a given number of parts and connect these by straight lines. The sum of these lines will be the more accurate the smaller the individual divided parts of the curve are. The same is true, only in a higher degree, of the calculation of whole planes, viz., triangles, rectangles, etc., and still more of solid bodies; the smaller the cubes are into which a given body is divided the more minute and accurate will be the resulting calculation of the contents of the whole body. principle both in physics and astronomy. same force which sustains the planets in their course also controls the fall of bodies. Newton showed that all bodies are attracted by the earth and that this attraction is a special case of the universal quality of matter. He not only stated the fact but also explained the law of gravitation. "Masses attract each other in the inverse ratio of the squares of their distances, but in the direct ratio of their masses." When he speaks of distance he refers, of course, in very large bodies to only two points, and for every two points the distance varies. Infinitesimal calculus again solves the question by finding the sum total of the distances between all the possible two points and then deducts from it the total effect of the two large bodies upon each other. Such is the method of the astronomer and physicist in searching for the common bond of a multitude of phenomena and in gaining a real insight into Newton applied this this multitude. He goes back to the effect of smallest particles in the sense of the infinitesimal calculus, i. e., to elementary effects. This method applies to the theories of heat, of electricity, of light; here, too, the laws of phenomena are established for infinitesimal parts, and from them the explanation of visible phenomena is derived. It was practically a similar idea upon which a hundred years later modern chemistry was established. Every one is familiar with the fundamental principles of chemical science; when, e. g. sulphur and iron are mixed in definite weight proportions and then heated a new substance is obtained, the properties of which are entirely different from those of its component element. Even the most careful microscopic examination fails to detect any traces of either sulphur or iron. A similar phenomenon is observed in the decomposition of acidulated water by the electric current; the resulting elments hydrogen and oxygen have nothing whatsoever in common with water; when these gases are carefully collected and measured they always represent two volumes of hydrogen and one volume of oxgyen, while their weight proportion is approximately that of one to eight. The first example illustrates the process of synthesis, the second that of analysis; both are opposite operations. These facts have led to the atomistic theory of matter, according to which matter is not infinitely divisible, not even in the sense of the infinitesimal calculus; on the contrary it has its ultimate limit in the atom, i. e., in the indivisible. The actual size of an atom, however, cannot be observed by the senses, no matter how powerful a microscope may be used. The variation of visible matter is due to the fact that the atoms of different simple elements combine to form the molecules of complex compounds. All visible matter is composed of such molecules. Every molecule of sulphide of iron contains an atom of iron and an atom of sulphur, and every molecule of water two atoms of hydrogen and one atom of oxygen, and just as atoms have to be thought of as separate in space, so likewise molecules. This conception may be taken as literal or merely symbolical; the latter view comes more and more to prevail. How important the infinitesimal has become in biology is a matter of universal experience. The study of the cell has revolutionized the whole sphere of medicine, and modern bacteriology has changed our entire mode of living. Compared with the atoms of the chemist these smallest elements are large; they lie within the limits of microscopic vision, especially since the wonderful discovery of certain color-stains. A large number of these vegetable tormentors of the human race are now successfully controlled by the master hand of the scientist. The fearful ravages of the socalled germ diseases would certainly have baffled the progress of the human race, if man had not thrown his searchlight beyond the boundary of vision into the realm of the invisible. The principle of comparison thus applied to the three important branches of the natural sciences shows us on the one hand a broad difference between the mathematico-physical and the chemico-biological factors, on the other hand, however, a close relation between the two; while the one presupposes the infinitesimal and unlimited divisibility the other is limited by the molecule, the cell, the bacterium, and yet both follow similar paths of investigation in certain other definite directions; the principle of energy in physics elaborated by the law of the conservation of energy, points to the same processes of thought known in biology by the name of embryological development. Both are investigations of the complex simultaneously introduced into science about fifty years ago; both created a tremendous stir in the world of thought. They lead us from the consideration of the minute to that of magnitudes. The law of the conservation of energy is made the universal topic of modern popular scientific lectures. Its applications are startling and dazzling at the same time. The transformation of heat into labor and vice versa can be very clearly exhibited through the steam engine, especially when connected with a set of electrical apparatus, for heat turned into electricity is almost entirely consumed either in the form of electricity, or of light or sound or magnetism. These facts have, moreover, become matters of everyday experience and need, therefore, no further demonstration, they do not deal primarily with the infinitesimal but with the gigantic; they have given our age its robust character. A parallel to this important physical law is furnished by certain complex results obtained in modern biology, indicated in the terms heredity, adaptation, struggle for existence, natural selection. Although the infinitesimal plays an important rôle in some of these phenomena, it is in no case open to scientific demonstration. Their influence upon social science, theology, philosophy and education has likewise been of a gigantic rather than of a minute character. The biological sciences have demonstrated the fact that scientific thinking is capable of mastering the most complicated material; they are of typical value for all complex conditions. The question now arises, what is the specific characteristic of scientific thinking, i. e., of thinking derived from the study of the natural sciences in their widest sense? The answer to this question leads us into an inquiry into the inductive and deductive methods of thought. Induction leads so to speak from the mouth of the river to its source; deduction from the source to the ocean. Deduction bases its conclusions upon an assured foundation, induction is searching for such a foundation. Deduction appeals to the force of logic, assured of the correctness of its premises; induction is constantly looking for objections and corrections on its way to a definite fundamental principle. Deduction is constantly exposed to objection and prejudice, its assurance is timid; induction is free from prejudice, it is not bound by any fundamental principle. Deduction lies nearer to the human mind than induction. The philosophers of the past very readily established all sorts of assumptions, upon which they built their airy systems. Aristotle speculated upon the fall of bodies; he assumes that the heavier of two stones would fall faster than the lighter in proportion to its weight, while science has established the fact that all bodies fall with equal rapidity. The establishment of fundamental premises is the most difficult problem in science. The nature student constantly tests his steps and findings, distrusting rather than trusting. The old deductive methods are the childhood |