The mechanical theory of the universe, in the ordinary sense, which deals with the mathematical formulation of the laws of planetary movement, had been the work of the seventeenth century. The eighteenth century had seen attempts to explain the status quo of the planetary system as a resultant from the evolution of an elementary molecular state of the cosmic mass. With the close of the eighteenth century there appeared a group of new sciences dealing with subtler energies of matter,—with electricity, galvanism, and above all with the connexions of chemical, electric, and magnetic science. The ideas thus suggested—embraced with some generality under the title Polarity—threw light backward upon the old mechanical conceptions, and gave them a decidedly dynamic character. Even the tranquil rest of geometrical figures came to be explained as a meeting point and transition moment of opposite forces. But these ideas produced an even greater effect on biology. Here, too, the need of a special 'vital force' to explain life and organisation disappeared: organism was but a higher stage, a completer truth of mechanism: and both found their explanation in the antithesis and synthesis of forces, or in differentiation and integration of what has recently been termed an 'idée-force.' In this direction, so far as Schelling was concerned, the obvious stimulus came from the programme sketched by Kielmeyer at Stuttgart in 1793, in a lecture 'on the proportions of organic forces,' According to Kielmeyer there are three types of force in the animal organisation, sensibility, irritability and reproduction[5]. The last of these is the basic force which builds up and propagates the animal system. With irritability, or contraction in response to external stimuli—material adaptation to environment—a higher level of animal life is reached. But the highest of all forces in the living being is sensibility. In this same order may we reasonably conceive that the 'plan of nature' proceeds. Her first products show little beyond that reproductive power which makes broad and high the pyramid of life. But as the creature acquires increasing heterogeneity and a comparatively independent position, it plays the part of a re-agent against stimuli, and a source of movements. Lastly, it not merely responds to, but assimilates and appropriates the impression into a sensation: it internalises the external, and carries within itself by means of the sensibility an ever-increasing picture of the world around it.
The idea of Evolution or Development, thus introduced by Schelling into philosophy as a governing principle in the study of matter and of mind, is not to be confused either with the older use of these terms or with their current applications to-day[6]. By evolution (or development) and involution (or envelopment) the earlier speculation on biology had denoted the view that the organic germ contained in parvo all that the matured organism showed in large. As the mature bulb of the healthy hyacinth shows, when cut open, to the naked eye, the stem and flowers that will issue from it next spring; so in general the seed can be treated as a miniature organism needing only an increase of bulk to make it fully visible in details. Growth is thus not accretion, but explication and enlargement of a microscopic organism subsisting in the germ.
Evolution, in the present time, and especially since Darwin, means something more than this. It implies a theory of descent of the variety of existing organisms from other organisms of a previous age, less individualised in forms and functions. From comparatively simple and homogeneous creatures there have issued in the course of ages creatures of more complex, more highly differentiated structure; and this process of gradual differentiation may be conceived as going on through an all but infinite period. At one end we may conceive matter, just endowed with the faculties of life and organisation, but in a minimal degree; at the other end of the developmental process, creatures which have organised within themselves powers, maximal both in range and variety. The result (so far as we at present go) is a genealogy of organism which, to quote Darwin, pictures before us a 'great tree of life which fills with its dead and broken branches the crust of the earth and covers the surface with its ever branching and beautiful ramifications.'
Even Bugon, seeing how naturally he could regard 'the wolf, the fox, and the jackal' as 'degenerate species of a single family,' concluded we could not go wrong in supposing that 'nature could have with time drawn from a single being all other organised beings.' Erasmus Darwin (1794) had insisted on the power of 'appetency' in the organs of a living creature to create and acquire new structures which it handed down to its posterity. G. R. Treviranus[7] in his Biology (1802-5) had noted the influence of environment, and Jean Lamarck in his Philosophie Zoologique (1809) had—after assuming that 'nature created none but the lowest organisms'—maintained that need and use (or disuse) can so effectively modify a creature that it may even produce new organs, and give rise by imperceptible degrees to a variety of creatures as widely divergent as they now appear. E. g. 'The giraffe owes its long neck to its continued habit of browsing upon trees.' And gradually it had become recognised by speculators on this subject that, as Mr. H. Spencer wrote in 1852, 'by small increments of modification any amount of modification may in time be generated.' Finally, in 1859, Darwin, with an ample resource of illustrative examples, enforced the doctrine that the existing fauna and flora of the earth represent the result of a struggle for existence, protracted during vast ages, in which those creature's have been preserved (selected to live) which, among all the variously-endowed offspring of any kind, were best fitted to appropriate the means of subsistence in the circumstances in which they for the time found themselves placed. The circumstances of life on the globe are perpetually varying from place to place and time to time: progeny never exactly reproduce their parents, and diverge widely from each other: hence each form of life is perpetually sliding on from phase to phase, and only those survive which are best adapted to the new conditions of life.
So far as Darwinism is an attempt to show that the classes of plants and animals are not a mere juxtaposition and aggregation, but are to be explained by reference to a single genetic principle, it is in harmony with the Evolution taught by Schelling and Hegel. Both alike overthrow the hard and fast lines of division which semi-popular science insists upon, and restore the continuity of existence. Both regard Nature as an organic realm, developing by action and re-action within itself, living a common life in thorough sympathy and solidarity, and not a mere machine in which the several parts retain without change the features and functions impressed upon them at creation by some supernal architect. But they differ in other points. Ordinary Darwinism, at least, talks as if circumstances and organism were independent originally, and only brought as it were, incidentally, in contact and correlation. It fails to keep hold of the fact—of which it is abstractly aware—that the two act upon and modify each other because they are members of a larger organism. It forgets, in short, what Schelling so thoroughly realised, that the organic and inorganic, ordinarily so called, are both in a wider sense organic. It wants the courage of recognising its own tacit presuppositions.
But the characteristic difference between the evolution theory of to-day and that meant by the philosophers is different from this, though connected with it. 'The assertion,' says Schelling, 'that the various organisms have formed themselves by gradual development from one another, is a misconception of an Idea which really lies in reason[8].' And Hegel no less decidedly asserts that 'Metamorphosis' (as the term was then applied, e. g. by Goethe, to what we now call Evolution) really exists as a fact only in the case of the living individual,—not in the supposed or theoretical continuity of the species. 'It is an awkward way both ancient and modern speculative biology have had of presenting the development and transition of one physical form and sphere into a higher one as an outwardly-actual production,—which, however, in order to make it clearer, has been thrown back into the darkness of the past.'[9] Yet notwithstanding these and even later protests, there is a great charm for many minds in the evolutionist picture, e. g., of the horse of to-day as the literal descendant through nearly fifty great stages (called species) from some creature of the eocene age, which gradually transformed itself in consequence of innate instability or variability of construction and in obedience to changes in its environment. But whatever value there may be in these as yet hypothetical aids to the imagination in grasping and unifying the variety of organic life, they run on another line from the philosophical evolution. That evolution is in the Idea, the Notion. It is the 'fluidity' of terms of thought that is here sought, not of the kinds of things,—except in a secondary way. And above all, philosophy does not deal with a problem in time, with a mere sequence; if it deals with a history of nature, the agents of that history are powers and forces—and powers which are ideal no less than real.
A nearer approach to the philosophic conception is to be found in the views which modern physiology takes of the nature of organic structure and function[10]. In the simplest phases of protoplasm, the apparently homogeneous mass is really undergoing a series of changes, and indeed only exists as such, because it is the ever-renewed resultant of two correlated processes,—a movement up (anabolic change) by which dead matter is assimilated and built into it, and a movement down (katabolic changes) by which its composing elements are disintegrated and left behind, with accompanying liberation of energy. Protoplasm or 'living matter' is the incessantly formed and re-formed thin line on which these two currents for the moment converge,-a temporary crest of white foam, as it were, raising itself on the Heraclitean wave of vicissitude, where all things flow on and nothing abides. But wherever protoplasm arises and maintains itself on this borderline of ascending and descending states, it exhibits the three well-known properties of assimilation, contractility, and sensitiveness. Protoplasm, placed as it were in the mean between these two processes, is or has the synthetic power which governs them and keeps them in one. It is no mere chemical substance, undergoing composition and decomposition, but rather, if looked at from the somewhat speculative standpoint of molecular physics, a kind of intricate movement or dance of particles, a shape or 'form' instinct with the power of producing and reproducing itself, and, ultimately, in some highly differentiated phases (nerve-system), with a power of producing and reproducing a world of imagination.
A philosophy of Nature is only half a philosophy. Its purport is to set free the spirit in nature, to release intelligence from its imprisonment in material encasements which hide it from the ordinary view, and to gather together the disjecta membra of the divine into the outlines of one continuous organisation. It seeks to spiritualise nature, i. e. to present the inner idea, unity, and genetic interdependence of all its phenomena: to delineate natura formaliter spectata not as a logical skeleton of abstract categories, but in its organisation and continuous life. There remains the problem of what Schelling calls 'Transcendental Idealism':—called 'transcendental' to avoid confusion with the vulgar idealism which supposes the world to be what it calls a mere 'idea' or phantom of the mind. Schelling's is on the contrary an 'Ideal-Realism': it 'materialises the laws of intelligence to laws of nature[11].'
We need not in details consider the genesis of Reality from the action of the Ego. Substantially it is the same as that given by Fichte. An activity, which is at once self-limiting and superior to all limit, rises through stage to stage, from sensation and intuition, to reflection and intelligence, till it becomes the consciousness of a world of ob; ective reality. 'Give me,' says the transcendental philosopher, 'a nature with opposing activities, of which the one goes to infinity, and the other endeavours to behold itself in this infinity,—and from that I will show you intelligence arising with the whole system of its ideas[12].' In the first phase the 'ideal-real' world arises by the synthetic action of the 'productive intuition,' Ideas, as it were, live and move: they grow and build up: causality is neither a category nor a schema, but an intelligent 'form' which is also a force—an 'idée-force,' They are (in the Hegelian sense) 'Ideas,' i.e. neither merely objective nor merely subjective, but both at once. But such an ideal world is outside and beyond consciousness: it belongs to the same region as that higher Ego where there is no distinction between the Ego I am and the Ego I know. To follow the movement in this region needs a combination of mental vision and visual intellect, which Schelling has called the 'Intellectual Intuition.' It is a power which rising above the materialism of sense yet retains its realism; which, while intellectual, is free from abstractness. It is synthetic, and widely different from mere logical analysis. It is, in short, analogous to the artistic genius: it creates a quasi-objectivity, an ideal-reality, without which the mere words of the speculator are meaningless. By means of this 'organ,' philosophy can 'freely imitate and repeat the original series of actions in which the one "act" of self-consciousness is evolved[13].
But the 'productive intuition' is, as Kant would say, blind: it is unconscious in its operation: and it is only after an arrest, a Sabbath when it surveys and judges its work, that it begins to realise itself through a process of analysis and reflection which elicits and fixes the categories that have been operative in it. By this abstraction intelligence rises out of mere production to intelligent and conscious production, i.e. to volition, where it has an ideal and realises it. With volition and voluntary action, objectivity is to appearance further certified and fortified. It is as active, i. e. as free, and even moral, agents, that we set forward categorically the reality of the world. So, too, Fichte had declared. But, as Schelling reminds us, with this intensified assertion of a law and an ideal to which the real must and shall correspond,—with the declaration that the realm of absolute consistency and ideal truth of reason is the true and real for ever and ever—we come across the fundamental antithesis of the 'Is' and the 'Ought,5 of the objective and subjective, of unconscious necessity and self-conscious freedom. With an attempt to get a philosophy of history,—i. e. of man and mind as the culminating truth of things, we see ourselves confronted with the opposition of fatalism and chance. On one hand history is only possible for beings who have an ideal in view,—one persistent aim and principle which their work and will is the means of realising. And yet it is an ideal which only the series of generations, only the whole race, can realise. Man's license to do or to refrain rests upon a larger, latent, divine necessity which constrains it. What human agents by their free choice determine and carry out, is carried out, in the long run, by the force of an everlasting and unchanging order, to which their wills seem but a mere plaything. But that man's free agency should thus harmonise with the constrained uniformities of nature is only possible on the assumption that both are phenomena of a common ground, or basis of identity, of an 'absolute identity, in which there is no duplication, and which for that reason, because the condition of all consciousness is duplication, can never reach consciousness. This ever-Unconscious, which, as it were the everlasting Sun in the spirit-kingdom, is hidden in its own undimmed light, and which, though it is never an object, still impresses its identity on all free objects, is simultaneously the same for all intelligences, the invisible "root" of which all intelligences are only the "powers," and the everlasting mediator between the self-determining subjective in us and the objective or percipient,—simultaneously the ground of the uniformity in freedom, and of the freedom in uniformity of the objective[14].' To rise to the sense of this Absolute Identity, as common basis of harmony between the 'Ought' and the 'Is,' is to recognise Providence: it is Religion.