But it must not be forgotten that Comte wrote his Positivist Philosophy long before the years 1856-1862, which, as stated above, suddenly widened the horizon of science and the world-concept of every educated man.

The works which appeared in these five or six years have wrought so complete a change in the views on nature, on life in general, and on the life of human societies, that it has no parallel in the whole history of science for the past two thousand years. That which had been but vaguely understood--sometimes only guessed at by the encyclopædists, and that which the best minds in the first half of the nineteenth century had so much difficulty in explaining, appeared now in the full armor of science; and it presented itself so thoroughly investigated through the inductive-deductive method that every other method was at once adjudged imperfect, false and--unnecessary.

Let us, then, dwell a little longer upon the results obtained in these years, that we may better appreciate the next attempt at a synthetic philosophy, which was made by Herbert Spencer.

Grove, Clausius, Helmholtz, Joule, and a whole group of physicists and astronomers, as also Kirchhoff, who discovered the spectroscopic analysis and gave us the means of determining the composition of the most distant stars,--these, in rapid succession at the end of the fifties, proved the unity of nature throughout the inorganic world. To talk of certain mysterious, imponderable fluids--calorific, magnetic, electrical--at once became impossible. It was shown that the mechanical motion of molecules which takes place in the waves of the sea or in the vibrations of a bell or a tuning fork, was adequate to the explanation of all the phenomena of heat, light, electricity and magnetism; that we can measure them and weigh their energy. More than this: that in the heavenly bodies most remote from us the same vibration of molecules takes place, with the same effects. Nay, the mass movements of the heavenly bodies themselves, which run through space according to the laws of universal gravitation, represent, in all likelihood, nothing else than the resultants of these vibrations of light and electricity, transmitted for billions and trillions of miles through interstellar space.

The same calorific and electrical vibrations of molecules of matter proved also adequate to explain all chemical phenomena. And then, the very life of plants and animals, in its infinitely varied manifestations, has been found to be nothing else than a continually going on exchange of molecules in that wide range of very complex, and hence unstable and easily decomposed, chemical compounds from which are built the tissues of every living being.

Then, already during those years it was understood--and for the past ten years it has been still more firmly established--that the life of the cells of the nervous system and their property of transmitting vibrations from one to the other, afforded a mechanical explanation of the nervous life of animals. Owing to these investigations, we can now understand, without leaving the domain of purely physiological observations, how impressions and images are produced and retained in the brain, how their mutual effects result in the association of ideas (every new impression awakening impressions previously stored up), and hence also--in thought.

Of course, very much still remains to be done and to be discovered in this vast domain; science, scarcely freed yet from the metaphysics which so long hampered it, is only now beginning to explore the wide field of physical psychology. But the start has already been made, and a solid foundation is laid for further labors. The old-fashioned classification of phenomena into two sets, which the German philosopher Kant endeavored to establish,--one concerned with investigations "in time and space" (the world of physical Phenomena) and the other "in time only" (the world of spiritual phenomena),--now falls of itself. And to the question once asked by the Russian physiologist, Setchenov: "By whom and how should psychology be studied?" science has already given the answer: "By physiologists, and by the physiological method." And, indeed, the recent labors of the physiologists have already succeeded in shedding incomparably more light than all the intricate discussions of the metaphysicists, upon the mechanism of thought; the awakening of impressions, their retention and transmission.

In this, its chief stronghold, metaphysics was thus worsted. The field in which it considered itself invincible has now been taken possession of by natural science and materialist philosophy, and these two are promoting the growth of knowledge in this direction faster than centuries of metaphysical speculation have done.

__________

In these same years another important step was made. Darwin's book on "The Origin of Species" appeared and eclipsed all the rest.

Already in the last century Buffon (apparently even Linnæus), and on the threshold of the nineteenth century Lamarck, had ventured to maintain that the existing species of plants and animals are not fixed forms; that they are variable and vary continually even now. The very fact of family likeness which exists between groups of forms--Lamarck pointed out--is a proof of their common descent from a common ancestry. Thus, for example, the various forms of meadow buttercups, water buttercups, and all other buttercups which we see on our meadows and swamps, must have been produced by the action of environment upon descendants from one common type of ancestors. Likewise, the present species of wolves, dogs, jackals and foxes did not exist in a remote past, but there was in their stead one kind of animals out of which, under various conditions, the wolves, the dogs, the jackals and the foxes have gradually evolved.

But in the eighteenth century such heresies as these had to be uttered with great circumspection. The Church was still very powerful then, and for such heretical views the naturalist had to reckon with prison, torture, or the lunatic's asylum. The "heretics" consequently were cautious in their expressions. Now, however, Darwin and A. R. Wallace could boldly maintain so great a heresy. Darwin even ventured to declare that man, too, had originated, in the same way of slow physiological evolution, from some lower forms of ape-like animals; that his "immortal spirit" and his "moral soul" are as much a product of evolution as the mind and the moral habits of the ant or of the chimpanzee.

We know what storms then broke out upon Darwin and, especially, upon his bold and gifted disciple, Huxley, who sharply emphasized just those conclusions from Darwin's work which were most dreaded by the clergy. It was a fierce battle, but, owing to the support of the masses of the public, the victory was won, nevertheless, by the Darwinians; and the result was that an entirely new and extremely important science--Biology, the science of life in all its manifestations--has grown up under our very eyes during the last forty years.

At the same time Darwin's work furnished a new key to the understanding of all sorts of phenomena--physical, vitals and social. It opened up a new road for their investigation. The idea of a continuous development (evolution) and of a continual adaptation to changing environment, found a much wider application than the origin of species. It was applied to the study of all nature, as well as to men and their social institutions, and it disclosed in these branches entirely unknown horizons, giving explanations of facts which hitherto had seemed quite inexplicable.

Owing to the impulse given by Darwin's work to all natural sciences, Biology was created, which, in Herbert Spencer's hands, soon explained to us how the countless forms of living beings inhabiting the earth may have developed, and enabled Haeckel to make the first attempt at formulating a genealogy of all animals, man included. In the same way a solid foundation for the history of the development of man's customs, manners, beliefs and institutions was laid down--a history the want of which was strongly felt by the eighteenth century philosophers and by Auguste Comte. At the present time this history can be written without resorting to either the formulæ of Hegelean metapysics or to "innate ideas" and "inspiration from without"--without any of those dead formulæ behind which, concealed bywords as by clouds, was always hidden the same ancient ignorance and the same superstition. Owing, on the one hand, to the labors of the naturalists, and, on the other, to those of Henry Maine and his followers, who applied the same inductive method to the study of primitive customs and laws that have grown out of them, it became possible in recent years to place the history of the origin and development of human institutions upon as firm a basis as that of the development of any form of plants or animals.

It would, of course, be extremely unfair to forget the enormous work that was done earlier--already in the thirties--towards the working out of the history of institutions by the school of Augustin Thierry in France, by that of Maurer and the "Germanists" in Germany, and in Russia, somewhat later, by Kostomárov, Belyáev and others. In fact, the principle of evolution had been applied to the study of manners and institutions, and also to languages, from the time of the encyclopædists. But to obtain correct, scientific deductions from all this mass of work became possible only when the scientists could look upon the established facts in the same way as the naturalist regards the continuous development of the organs of a plant or of a new species.

The metaphysical formulæ have helped, in their time, to make certain approximate generalizations. Especially did they stimulate the slumbering thought, disturbing it by their vague hints as to the unity of life in nature. At a time when the inductive generalizations of the encyclopædists and their English predecessors were almost forgotten (in the first half of the nineteenth century), and when it required some civic courage to speak of the unity of physical and spiritual nature--the obscure metaphysics still upheld the tendency toward generalization. But those generalizations were established either by means of the dialectic method or by means of a semi-conscious induction, and, therefore, were always characterized by a hopeless indefiniteness. The former kind of generalizations was deduced by means of really fallacious syllogisms--similar to those by which in ancient times certain Greeks used to prove that the planets must move in circles "because the circle is the most perfect curve;" and the meagerness of the premises would then be concealed by misty words, and, worse still, by an obscure and clumsy exposition. As to the semi-conscious inductions which were made here and there, they were based upon a very limited circle of observations--similar to the broad but unwarranted generalization of Weissmann, which have recently created some sensation. Then, as the induction was unconscious the generalizations were put forth in the shape of hard and fast laws, while in reality they were but simple suppositions--hypotheses, or beginnings only of generalizations, which, far from being "laws," required yet the very first verification by observation. Finally, all these broad deductions, expressed as they were in most abstract forms--as, for instance, the Hegelean "thesis, antithesis, and synthesis,"--left full play for the individual to come to the most varied and often opposite practical conclusions; so that they could give birth, for instance, to Bakunin's revolutionary enthusiasm and to the Dresden Revolution, to the revolutionary Jacobinism of Marx and to the recognition of the "reasonableness of what exists," which reconciled so many Germans to the reaction then existing--to say nothing of the recent vagaries of the so-called Russian Marxists.

(Source: Translated by David A. Modell and published by The Social Science Club of Philadelphia in 1903.)