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Chapter VII
NINETEENTH-CENTURY SCIENCE AND PHILOSOPHIC THOUGHT
General Tendencies of Scientific Thought—Matter and Force— The Theory of Energy—Psychology—Biology and Materialism —Science and Sociology—Evolution and Religion—Evolution and Philosophy.
In the seventeenth and eighteenth centuries the influence General of that nationalism which replaced the ecclesiastical uni- Tendencies versalism of the Middle Ages began to be apparent. Science, r^^ht^ indeed thought in general, acquired strongly-marked national characters and was accompanied by an intellectual separation between the nations, while the several vernacular languages of Europe superseded Latin as the vehicle for scientific writing. Journeys of intellectual discovery, such as those of Voltaire to England in 1726, of Adam Smith to France in 1765, and of Wordsworth and Coleridge to Germany in 1798, had-to be undertaken before the Newtonian astronomy, the economics of the "physiocrats", or the philosophy of Kant and Schelling could become known in countries other than those of their authors.1
In the early years of the nineteenth century the scientific centre of the world was Paris. In 1798 the Revolutionary Government had guillotined Lavoisier, Bailly, and Cousin, driven Condorcet to suicide, and suspended theAcadémie des Sciences. But it soon found that, it had to appeal for help to the former members of that Society: " everything was wanting for the defence of the country", science became a necessity to society at large, and in 1795 theAcadémiewas reopened as part of theInstituí.The mathematics of Laplace, Lagrange and Monge, the new chemistry initiated by Lavoisier, and the geometrical crystallography created by the Abbé Haüy, united to form a brilliant constellation of physical sciences.
The theory of probability, founded by Pascal and Fermat in the seventeenth century, was developed into a system by Laplace, and applied not only to estimate the errors of physical
1 J. T. Men, History of European Thought in the Nineteenth Century, 4 vols. Edinburgh and London, 1806-1814, vol. i, p. 16.
General measurement but also to rationalize such human affairs as Tendencies insurance and the statistics of the problems of government and of Scientific administration where large numbers are involved. Cuvier carried exact research into comparative anatomy, and, in his position as permanent secretary of theAcadémie des Sciences, did much to keep the scientific spirit up to a high standard in all subjects.
During the eighteenth century it was in France alone that science permeated literature; "no other country has a Fon- tenelle, a Voltaire, a Buffon"; and in the early nineteenth century this connection between science and literature was maintained on a lofty and dignified plane, largely owing to the constitution of theAcadémieas part of theInstituí.
If the home of French science is to be found in theAcadémie, that of German lay in the Universities. But long after the methods of exact science were being used in Paris, the German Universities, while eminent in classical and philosophic studies, were teaching a hybrid Naturphilosophie, which deduced its conclusions from doubtful philosophic theories, instead of obtaining them by the patient study of natural phenomena. About 1880 this influence died away, partly owing to the mathematics of Gauss and to the chemical work of Liebig, who, trained at Paris under Gay-Lussac, had opened a laboratory at Giessen in 1826. From then onwards, the systematic organization of research has been carried further in Germany than in any other country, and German com- pendiums and analyses of the world's work have been preeminent. Moreover the wider meaning of the word Wissenschaft, which includes all systematic knowledge, whether in what we should call science or in philology, history and philosophy, has done much to keep all these subjects in touch with each other and to give them all a correspondingly wider outlook.
Perhaps the most striking peculiarity of English science has been its individualist spirit, and the frequency with which work of brilliant genius has been done by those of no academic position. This is illustrated by a list of the great men of science of the first half of the nineteenth century, when Oxford and Cambridge, unrivalled as places of liberal education, were not yet awake to the continental spirit of research. Complaints were frequent that the state of science was low in England,1
1 See for example, Edinburgh Review, vol. xxvii, 1816, p. 98, and C. Babbage, Decline of the State of Science in England, 1880.
and it needed the stimulus of an undergraduate society, General formed by Babbage, Herschel and Peacock, to introduce Tendencies continental mathematics, largely developed though they were Scientific from those of Newton, into the University of Cambridge. Thought
But, in the middle of the century, Oxford and Cambridge were reformed, and rapidly became as efficient in modern studies as in the graceful activities which they had inherited from earlier times. Mathematical physics, first of the sciences, found once more a congenial home in Cambridge, and later, under the inspiration of Clerk Maxwell, Lord Rayleigh and J. J. Thomson, the world-famous experimental school of the Cavendish Laboratory grew up. The biological subjects followed, under the leadership of Michael Foster, Langley and Bateson, and Cambridge took its place as the great home of science we know to-day.
Thus, during the second half of the nineteenth century, the intellectual isolation of the nations of Europe, which had lasted through the first half, was again broken down. Facilities of transport increased personal intercourse, scientific periodicals and the proceedings of learned societies brought new results to the cognizance of all those interested, and science became once more international.
On the other hand, the different departments of knowledge became more specialized, and, as national barriers were overthrown, departmental isolation increased. At the beginning of the nineteenth century it was still possible for German Universities to have courses of lectures on Encyclopcidie, under the impression that unity and completeness of knowledge could be found in one and the same arrangement of study.1 Philosophy, under the influence of Kant, Fichte and Schleier- macher, still took into account all branches of knowledge, and in its turn still permeated scientific thought.
How science and philosophy for a time lost touch with each other will be described later. The process was doubtless hastened by the simultaneous segregation of science into sciences. The growth of knowledge went on so fast that no man could keep track of it all. Meanwhile laboratories, which hitherto had been the private rooms of individual "natural philosophers were built and endowed by or for Universities, and brought the experimental method of study not only to 1 Mere, hoc. ext. vol. I, p. 87.
General those who were advancing knowledge by research, but also to Tendencies the more elementary student. The opportunities thus provided of Sdentijkfor the more thorough study of each subject left less time for general surveys, and men of science tended not to see their wood for its trees. In recent years inter-connections between the different sciences are becoming more and more apparent, while mathematics and physics are pointing the way to a new philosophy. But, speaking generally, the fissiparous tendencies lasted till the end of the nineteenth century, save for a few broad generalizations, such as the principle of the conservation of energy, which was 3een to hold good in physics, chemistry and biology alike.
In attempting to trace the effect produced on other subjects, and especially on philosophic thought, by the growth of science during the nineteenth century, it must not be forgotten that, as already pointed out, the effect during this period of the advance in mathematics and physics was much less than it had been in the sixteenth, seventeenth and eighteenth centuries. The volume of mathematical and physical research was far greater, and the change in scientific outlook which took place between the years 1800 and 1900 was enormous, yet, from the point of view of philosophy, no such revolutionary physical discoveries were made in that century as those of Copernicus and Newton, which altered so profoundly man's idea of the position and importance in the Universe of his world and himself. In the nineteenth century a like revolutionary result came from biology, when physiology and psychology examined the relations of mind and matter, and again when the theory of evolution was established by Darwin on the basis of natural selection.
During the Renaissance and the Newtonian Epoch, we have seen the links between science and philosophy gradually loosened by the action of men of science in devising a new method of induction and experiment proper to the study of nature. Yet the philosophers tried to maintain a de jure suzerainty over the whole field of knowledge, even though <U facto the sovereignty over a large part of it had passed from them. Till the days of Kant they still framed their systems to include the results of physical science.
But we now come to a time when, chiefly owing to the influence of later Hegelians rather than of Hegel himself, the
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separation between science and philosophy became much more General distinct.Tendencies
The story is well told by Helmholtz,[1] who, writing in 1862, was near enough to the time fully to appreciate its effects:
It has been made of late a reproach against natural philosophy that it has struck out a path of its own, and has separated itself more and more widely from the other sciences [Wissenschaften] which are united by common philological and historical studies. This opposition has, in fact, been long apparent, and seems to me to have grown up mainly under the influence of the Hegelian philosophy, or, at any rate, to have been brought out into more distinct relief by that philosophy. Certainly, at the end of the last century, when Kantian philosophy reigned supreme, such a schism had never been proclaimed; on the contrary, Kant's philosophy rested on exactly the same ground as the physical sciences, as is evident from his own scientific works, especially from his "Cosmogony", based upon Newton's Law of Gravitation, which afterwards, under the name of Laplace's Nebular Hypothesis, came to be universally recognized. The sole object of Kant's "Critical Philosophy" was to test the sources and the authority of our knowledge, and to fix a definite scope and standard for the researches of philosophy, as compared with other sciences. According to his teaching, a principle discovered a priori by pure thought was a rule applicable to the method of pure thought, and nothing further; it could contain no real, positive knowledge. [Hegel's] "Philosophy of Identity"* was bolder. It started with the hypothesis that not only spiritual phenomena, but even the actual world—nature, that is, and man—were the result of an act of thought on the part of a creative mind, similar, it was supposed, in kind to the human mind. On this hypothesis it seemed competent for the human mind, even without the guidance of external experience, to think over again the thoughts of the Creator, and to rediscover them by its own inner activity. Such was the view with which the "Philosophy of Identity " set to work to construct a priori the results of other sciences. The process might be more or less successful in matters of theology, law, politics, language, art, history, in short in all sciences, the subject- matter of which really grows out of our moral nature, and which are therefore properly classed together under the name of moral sciences.... But even granting that Hegel was more or less successful in constructing, a priori, the leading results of the moral sciences, still it was no proof of the correctness of the hypothesis of Identity with which he started. The facts of nature would have been the crucial test.... It was at this point that Hegel's philosophy, we venture to say, utterly broke down. His system of nature seemed, at least to natural philosophers, absolutely crazy. Of all the distinguished scientific men who were his contemporaries, not one was found to stand up for his ideas. Accordingly, Hegel himself, convinced of the importance of winning for his philosophy in
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General the field of physical science that recognition which had been so freely Tendencies accorded to it elsewhere, launched out, with unusual vehemence and of Scientific acrimony, against the natural philosophers, and especially against Sir Thought Isaac Newton, as the first and greatest representative of physical investigation. The philosophers accused the scientific men of narrowness; the scientific men retorted that the philosophers were crazy. And so it came about that men of science began to lay some stress on the banishment of all philosophic influences from their work; while some of them, including men of the greatest acuteness, went so far as to condemn philosophy altogether, not merely as useless, but as mischievous dreaming. Thus, it must be confessed, not only were the illegitimate pretensions of the Hegelian system to subordinate to itself all other studies rejected, but no regard was paid to the rightful claims of philosophy, that is, the criticism of the sources of cognition, and the definition of the functions of the intellect.
For about half a century, especially in Germany, this separation between science and philosophy persisted. The Hegelians despised the experimentalists, somewhat as did the Greek philosophers. The men of science disliked and finally ignored the Hegelians. Even Helmholtz, in deploring this attitude, as is seen above, limited philosophy to its critical function—the elucidation of the theory of knowledge—and denied its claim to attack other more speculative problems, such as the deeper questions of the nature of reality and the meaning of the Universe.
The philosophers, from their side, were equally blind, and used any weapon which came to their hand in their attack on the experimentalists. The poet Goethe had done good work in both animal and vegetable comparative anatomy, where the facts lay on the surface. But where deeper analysis was needed, as in physics, Goethe's method failed. A flash of poetic insight assured him that white light must be simpler and purer than coloured, and that therefore Newton's theory of colour must be wrong.1 He would not consider the facts brought out by careful experiment or the inferences drawn from them. To him the senses must reveal at once the truth about nature, and the true inwardness of things be made visible by direct aesthetic imagination. He therefore framed a theory of colour in which white light was fundamental—a theory which could not stand the simplest physical analysis, and was supported by nothing but Goethe's abuse of Newton and by the compromising help of the Hegelians. It is not surprising that the men of
1 Helmholtz, loc. cit. p. 88.
science learnt to ignore the writings of the philosophers. But General the complete separation could not last long, and science soon Tendencies began once more to influence the general thought of the time. ^Scientfa
In England a new variety of an old controversy arose u between Whewell on the one hand, who maintained the a priori nature of mathematics, and Herschel and John Stuart Mill on the other, who held that Euclidean axioms, such as that two parallel straight lines produced to infinity can never meet, are inductions from experience.1 Kant referred the validity of these axioms, as Of other scientific concepts, to the nature of our minds, and nowadays the axioms might be regarded as mere definitions of the kind of space we were going to investigate in our geometry. Other axioms can be framed which lead to a geometry of non-Euclidean space. Indeed the work of Lobatchewski, Bolyai, Gauss and Riemann gradually showed that what we call space is a particular case of a general possible manifoldness which may have four or more dimensions. Our minds can frame the axioms and investigate the properties of these other kinds of "space". Experience, it is true, shows that the space we observe is approximately three dimensional and Euclidean, but, examined more accurately by Einstein, it proved to be not exactly so, but to conform, as far as present accuracy goes, to one out of the many other possible kinds of space. Thus the Whewell-Mill controversy, like so many others, has faded away into a solution which contains the essence of both alternatives.
Whewell distinguished the necessary axioms of mathematics from the merely probable hypotheses of natural science, which he recognized as being based on induction from experience, though, following Kant, he held that in every act of knowledge a formal or mental element co-operates with an element derived directly from sensation. Mill's attitude is partly due to the fact that, in his day, empiricists were still opposing, consciously or unconsciously, the old phantom of innate ideas—Platonic revelations from a super-sensual world. The same survival seems to have misled Ueberweg in his polemic against Kant.2 Nineteenth-century empiricists often failed to see the strength or bearings of the view that experience does