Evolution (or Evolutionism) is the view that the whole world and all it contains was not established once for all, but that it is in a state of perpetual motion and development.
I. Scope of the Term : As a metaphysical theory evolution is distinguished from the doctrine of Emanation (q.v.) by the fact that according to the latter the primal principle remains unchanged in quantity and quality in spite of every efflux and development proceeding from it; while according to the theory of development in its logical completeness nothing is excluded from the process of development or changenot even the original principle itself, if any such is assumed. Another point of difference is, that in the doctrine of emanation the development proceeds by various stages from the highest to ever lower stages, while evolution works continually toward what is higher and more perfect. Both these theories, and especially the latter, are opposed to that of creation, according to which the whole world and the matter contained in it are the products of a free and conscious act of God; and they are opposed equally to the sort of dualism, in the main Platonic, which conceives a permanent world of ideas in contrast with a mutable matter still to be formed and derives the visible phenomena from the influence of the former upon the latter. In a narrower biological sense evolution often means the development of organic beings from inorganic matter, and their further descent from one another. In the views of the evolutionistic school two different tendencies are to be distinguished. One is teleological, or more broadly organic, which deduces motion and change from internal causes or purposes inherent in the things subject to the process. This view is found not seldom in the older philosophers, and also in the modern, especially the German idealists. The other may be called the mechanical, since it ascribes the changes to external causes. This is the view chiefly held by modern evolutionists.
The terms evolution and development in this sense are of comparatively recent origin, and when they first make their appearance relate not to the entire universe but to some special partial process. The doctrine, however, which is now meant by them, appears in the early stages of Greek philosophy, and traces of it may be found in Oriental thought. The terms evolution and evolutionism, though f¿und in a partially analogous sense as early as Nicholas of Cusa, and in Leibnitz and other seventeenth and eighteenth century philosophers in a sense still nearer to the modern, seem to have gained their full import first in England. They are now used also by French and German writers, and designate what forms an important, if not the central, point in the modern conception of the world.
II. Darwin's Greek Predecessors:
1. Anaximender and Epicurus. Evolution is not so much a modern discovery as some of its advocates would have us believe. It made its appearance early in Greek philosophy, and maintained its position more or less, with the most diverse modifications, and frequently confused with the idea of emanation, until the close of ancient thought. The Greeks had, it is true, no term exactly equivalent to "evolution"; but when Thales asserts that all things originated from water; when Anaximenes calls air the principle of all things, regarding the subsequent process as a thinning or thickening, they must have considered individual beings and the phenomenal world as a result of evolution, even if they did not carry the process out in detail. Anaximander is often regarded as a precursor of the modern theory of development. He deduces living beings, in a gradual development, from moisture under the influence of warmth, and suggests the view that men originated from animals of another sort, since if they had come into existence as human beings, needing fostering care for a long time, they would not have been able to maintain their existence. In Empedocles, as in Epicurus and Lucretius, who follow in his footsteps, there are rudimentary suggestions of the Darwinian theory in its broader sense; and here too, as with Darwin, the mechanical principle comes in; the process is adapted to a certain end by a sort of natural selection, without regarding nature as deliberately forming its results for these ends.
2. Heraclitus and the Stoics. If the mechanical view is to be found in these philosophers, the teleological occurs in Heraclitus, who conceives the process as a rational development, in accordance with the Logos, and names steps of the process, as from igneous air to water, and thence to earth. The Stoics followed Heraclitus in the main lines of their physics. The primal principle is, as with him, igneous air. only that this is named God by them with much greater definiteness. The Godhead has life in itself, and develops into the universe, differentiating primarily into two kinds of elementsthe finer or active, and the coarser or passive. Formation or development goes on continuously, under the impulse of the formative principle, by whatever name it is known, until all is once more dissolved by the ekpyrōsis into the fundamental principle, and the whole process begins over again. Their conception of the process as analogous to the development of the seed finds special expression in their term of logos spermatikos. In one point the Stoics differ essentially from Heraclitus. With them the whole process is accomplished according to certain ends indwelling in the Godhead, which is a provident, careful intelligence, while no providence is assumed in Heraclitus.
3. Empedocles and Democritus. Empedocles asserts definitely that the sphairos, as the full reconciliation of opposites, is opposed, as the superior, to the individual beings brought into existence by hatred, which are then once more united by love to the primal essence, the interchange of world-periods thus continuing indefinitely. Development is to be found also in the atomistic philosopher Democritus; in a purely mechanical manner without any purpose, bodies come into existence out of atoms, and ultimately entire worlds appear and disappear from and to eternity. Like his predecessors, Democritus, deduces organic beings from what is inorganicmoist earth or slime.
4. Plato and Aristotle. Development, as well as the process of becoming in general, was denied by the Eleatic philosophers. Their doctrine, diametrically opposed to the older thoroughgoing evolutionism, had its influence in determining the acceptance of unchangeable ideas, or forms, by Plato and Aristotle. Though Plato reproduces the doctrine of Heraclitus as to the flux of all things in the phenomenal world, he denies any continuous change in the world of ideas. Change is permanent only in so far as the eternal forms stamp themselves upon individual objects. Though this, as a rule, takes place but imperfectly, the stubborn mass is so far affected that all works out as far as possible for the best. The demiurge willed that all should become as far as possible like himself; and so the world finally becomes beautiful and perfect. Here we have a development, though the principle which has the most real existence does not change; the forms, or archetypal ideas, remain eternally what they are.
In Aristotle also the forms are the real existences, working in matter but eternally remaining the same, at once the motive cause and the effectual end of all things. Here the idea of evolution is clearer than in Plato, especially for the physical world, which is wholly dominated by purpose. The transition from lifeless to living matter is a gradual one, so that the dividing-line between them is scarcely perceptible. Next to lifeless matter comes the vegetable kingdom, which seems, compared with the inorganic, to have life, but appears lifeless compared with the organic. The transition from plants to animals is again a gradual one. The lowest organisms originate from the primeval slime, or from animal differentiation; there is a continual progression from simple, undeveloped types to the higher and more perfect. As the highest stage, the end and aim of the whole process, man appears; all lower forms are merely unsuccessful attempts to produce him. The ape is a transitional stage between man and other viviparous animals. If development has so important a work in Aristotle's physics, it is not less important in his metaphysics. The whole transition from potentiality to actuality (from dynamis to entelecheia) is nothing but a transition from the lower to the higher, everything striving to assimilate itself to the absolutely perfect, to the Divine. Thus Aristotle, like Plato, regards the entire order of the universe as a sort of deification. But the part played in the development by the Godhead, the absolutely immaterial form, is less than that of the forms which operate in matter, since, being already everything, it is incapable of becoming anything else. Thus Aristotle, despite his evolutionistic notions, does not take the view of a thoroughgoing evolutionist as regards the universe; nor do the Neoplatonists, whose highest principle remains wholly unchanged, though all things emanate from it.
III. Medieval Views:
1. Augustine, Erigena, and Cusa. No more absolutely than with Plato and Aristotle was the idea of evolution accepted by patristic and scholastic theology and philosophy, both on account of the dualism which runs through them as an echo of the two great Greek masters, and on account of the generally accepted Christian theory of creation. However, evolution is not generally denied; and with Augustine (De civitate dei, xv. 1) it is taken as the basis for a philosophy of history. Erigena and some of his followers seem to teach a sort of evolution. The issue of finite beings from God is called analysis or resolutio, in contrast to the reversio, or deificatio, the return to God, who once more assimilates all things. God himself, although denominatedthe beginning, middle, and end, all in allremains unmixed in his own essence, transcendent though immanent in the world. The teaching of Nicholas of Cusa is similar to Erigena's, though a certain amount of Pythagoreanism comes in here. The world exhibits explicitly what the Godhead implicitly contains; the world is an animated, ordered whole, in which God is everywhere present. Since God embraces all things in himself, he unites all opposites: he is the complicatio omnium contradictoriorum. The idea of evolution thus appears in Nicholas in a rather pantheistic form, but it is not logically carried out.
2. Giordano Bruno. In spite of some obscurities in his conception of the world Giordano Bruno is a little clearer. According to him God is the immanent first cause in the universe; there is no difference between matter and form; matter, which includes in itself forms and ends, is the source of all becoming and of all actuality. The infinite ether which fills infinite space conceals within itself the nucleus of all things, and they proceed from it according to determinate laws, yet in a teleological manner. Thus the worlds originate not by an arbitrary act, but by an inner necessity of the divine nature. They are natura naturata, as distinguished from the operative nature of God, natura naturans, which is present in all things as the being of all that is, the beauty of all that is fair. As in the Stoic teaching, with which Bruno's philosophy has much in common, the conception of evolution comes out clearly both for physics and metaphysics.
IV. The Theory in Modern Philosophy:
1. Descartes, Leibnitz, Herder. Leibnitz attempted to reconcile the mechanical-physical and the teleological views, after Descartes, in his Principia philosophis, excluding all purpose, had explained nature, both lifeless and living, as mere mechanism. It is right, however, to point out that Descartes had a meta-physics above his physics, in which the conception of God took an important place, and that thus the mechanical notion of evolution did not really include everything. In Leibnitz the principles of mechanics and physics are dependent upon the direction of a supreme intelligence, without which they would be inexplicable to us. Only by such a preliminary assumption are we able to recognize that one ordered thing follows upon another continuously. It is in this sense that the law of continuity is to be understood, which is of such great importance in Leibnitz. At bottom it is the same as the law of ordered development. The genera of all beings follow continuously one upon another, and between the main classes, as between animals and vegetables, there must be a continuous sequence of intermediate beings. Here again, however, evolution is not taught in its most thorough form, since the divine monad, of God, does not come into the world but transcends it.
Among the German philosophers of the eighteenth century Herder must be mentioned first of the pioneers of modern evolutionism. He lays down the doctrine of a continuous development in the unity of nature from inorganic to organic, from the stone to the plant, from the plant to the animal, and from the animal to man. As nature develops according to fixed laws and natural conditions, so does history, which is only a continuation of the process of nature. Both nature and history labor to educate man in perfect humanity; but as this is seldom attained, a future life is suggested. Lessing had dwelt on the education of the human race as a development to the higher and more perfect. It is only recently that the significance of Herder, in regard to the conception and treatment of historic development, has been adequately recognized. Goethe also followed out the idea of evolution in his zoological and botanical investigations, with his theory of the metamorphosis of plants and his endeavor to discover unity in different organisms.
2. Kant, Shelling, and Others. Kant is also often mentioned as having been an early teacher of the modern theory of descent. It is true he considers the analogy of the forms which he finds in various classes of organisms a ground for supposing that they may have come originally from a common source. He calls the hypothesis that specifically different beings have originated one from the other "a daring adventure of the reason." But he entertains the thought that in a later epoch "an orang-outang or a chimpanzee may develop the organs which serve for walking, grasping objects, and speakingin short, that he may evolve the structure of man, with an organ for the use of reason, which shall gradually develop itself by social culture." Here, indeed, important ideas of Darwin were anticipated; but Kents critical system was such that development could have no predominant place in it.
The idea of evolution came out more strongly in his German idealistic successors, especially in Schelling, who regarded nature as a preliminary stage to mind, and the process of physical development as continuing in history. The unconscious productions of nature are only unsuccessful attempts to reflect itself; lifeless nature is an immature intelligence, so that in its phenomena an intelligent character appears only unconsciously. Its highest aim, that of becoming an object to itself, is only attained in the highest and last reflectionin man, or in what we call reason, through which for the first time nature returns perfectly upon itself. All stages of nature are connected by a common life, and show in their development a conclusive unity. The course of history as a whole must be conceived as offering a gradually progressive revelation of the Absolute. For this he names three periodsthat of fate, that of nature, and that of providence, of which we are now in the second. Schellings followers carried the idea of development somewhat further than their master. This is true especially of Oken, who conceives natural science as the science of the eternal transformation of God into the world, of the dissolution of the Absolute into plurality, and of its continuous further operation in this plurality. The development is continued through the vegetable and animal kingdoms up to man, who in his art and science and polity completely establishes the will of nature. Oken, it is true, conceived man as the sole object of all animal development, so that the lower stages are only abortive attempts to produce hima theory afterward controverted by Ernst von Baer and Cuvier, the former of whom, standing somewhat in opposition to Darwin, is of great interest to the student of the history of the theory of evolution.
3. Schleiermacher and Hegel. Some evolutionistic ideas are found in Krause and Schleiermacher; but Hegel, with his absolute idealism, is a more notable representative of them. In his system philosophy is the science of the Absolute, of the absolute reason developing or unfolding itself. Reason develops itself first in the abstract element of thought, then expresses itself externally in nature, and finally returns from this externalization into itself in mind. As Heraclitus had taught eternal becoming, so Hegel, who avowedly accepted all the propositions of the Ephesian philosopher in his logic, taught eternal proceeding. The difference between the Greek and the German was that the former believed in the flux of matter, of fire transmuting itself by degrees into all things, and in nature as the sole existence, outside of which there was nothing; while the latter conceived the abstract idea or reason as that which really is or becomes, and nature as only a necessary but transient phase in the process of development. With Heraclitus evolution meant the return of all things into the primal principle followed by a new world-development; with Hegel it was an eternal process of thought, giving no answer to the question as to the end of historical development.
4. Lamarck and Darwin. While Heraclitus had laid down his doctrine of eternal becoming rather by intuition than on the ground of experience, and the entire evolutionary process of Hegel had been expressly conceived as based on pure thought, Darwins epoch-making doctrine rested upon a vast mass of ascertained facts. He was, of course, not the first to lay down the origin of species one from another as a formal doctrine. Besides those predecessors of his to whom allusion has already been made, two others may be mentioned here: his father, Erasmus Darwin, who emphasized organic variability; and still more Lamarck, who denied the immutability of species and forms, and claimed to have demonstrated by observation the gradual development of the animal kingdom. What is new in Charles Darwin is not his theory of descent, but its confirmation by the theory of natural selection and the survival of the fittest in the struggle for existence. Thus a result is brought about which corresponds as far as possible to a rational end in a purely mechanical process, without any cooperation of teleological principles, without any innate tendency in the organisms to proceed to a higher stage. This theory postulates in the later organisms deviations from the earlier ones, and that these deviations, in so far as they are improvements, perpetuate themselves and become generic marks of differentiation. This, however, imports a difficulty, since the origin of the first of these deviations is inexplicable. The differentia of mankind, whom Darwin, led by the force of analogy, deduces from a species of apes, consists in intellect and moral qualities, but comes into existence only by degrees. The moral sensibilities develop from the original social impulse innate in man; this impulse is an effort to secure not so much individual happiness as the general welfare.
5. Haeckel, Fouillée, Guyau. It would be impossible to name here all those who, in different countries, have followed in Darwins footsteps, first in the biological field and then in those of psychology, ethics, sociology, and religion. They have carried his teaching further in several directions, modifying it to some extent and making it fruitful, while positivism has not seldom come into alliance with it. In Germany Ernst Haeckel must be mentioned with his biogenetic law, according to which the development of the individual is an epitome of the history of the race, and with his less securely grounded notion of the world-ether as a creative deity. In France Alfred Fouillée worked out a theory of idea-forces, a combination of Platonic idealism with English (though not specifically Darwinian) evolutionism. Marie-Jean Guyau understood by evolution a life led according to the fundamental law that the most intensive life is also the most extensive. He develops his ethics altogether from the facts of the social existence of mankind, and his religion is a universal sociomorphism, the feeling of the unity of man with the entire cosmos.
6. Herbert Spencer. The most careful and thorough development of the whole system took place in England. For a long time it was represented principally by the work of Herbert Spencer, who had come out for the principle of evolution even before the publication of Darwin's Origin of Species. He carries the idea through the whole range of philosophy in his great System of Synthetic Philosophy and undertakes to show that development is the highest law of all nature, not merely of the organic. As the foundation of all that exists, though itself unknowable and only revealing itself in material and mental forms, he places a power, the Absolute, of which we have but an indefinite conception. The individual processes of the world of phenomena are classed under the head of evolution, or extension of movement, with which integration of matter, union into a single whole, is connected, and dissolution or absorption of movement, which includes disintegration of matter, the breaking of connection. Both processes go on simultaneously, and include the history of every existence which we can perceive. In the course of their development the organisms incorporate matter with themselves; the plant grows by taking into itself elements which have previously existed in the form of gases, and the animal by assimilating elements found in plants and in other animals. The same sort of integration is observed in social organisms, as when nomadic families unite into a tribe, or subjects under a prince, and princes under a king. In like manner integration is evident in the development of language, of art, and of science, especially philosophy. But as the individuals unite into a whole, a strongly marked differentiation goes on at the same time, as in the distinction between the surface and the interior of the earth, or between various climates. Natural selection is not considered necessary to account for varying species, but gradual conditions of life create them. The aim of the development is to show a condition of perfect balance in the whole; when this is attained, the development, in virtue of the continuous operation of external powers, passes into dissolution. Those epochs of development and of dissolution follow alternately upon each other. This view of Spencer suggests the hodos anō and hodos katō of Heraclitus, and his flowing back of individual things into the primal principle.
Similar principles are carried out not only for organic phenomena but also for mental and social; and on the basis of the theory of evolution a remarkable combination of intuitionism and empiricism is achieved. In his principles of sociology Spencer lays down the laws of hyperorganic evolution, and gives the various stages of human customs and especially of religious ideas, deducing all religion much too one-sidedly from ancestor-worship. The belief in an immortal "second self" is explained by such phenomena as shadows and echoes. The notion of gods is supposed to arise from the idea of a ghostly life after death. In his Principles Of Ethics he attempts a similar compromise between intuitionism and empiricism, deducing the consciousness of duty from innumerable accumulated experiences. The compelling element in moral actions, originally arising from fear of religious, civil, or social punishment, disappears with the development of true morality. There is no permanent opposition between egoism and altruism, but the latter develops simultaneously with the former.
7. Modifications of Spencer. Spencer's ethical principles were fruitfully modified, especially by Sir Leslie Stephen and S. Alexander though with constant adherence to the idea of development. While the doctrine of evolution in Huxley and Tyndall is associated with agnosticism, and thus freed from all connection with metaphysics, as indeed was the case with Spencer, in spite of his recognition of the Absolute as the necessary basis for religion and for thought, in another direction an attempt was made to combine evolutionism closely with a metaphysics in which the idea of God was prominent. Thus the evolution theory of Clifford and Romanes led them to a thoroughgoing monism, and that of J. M. F. Schiller to pluralism. According to the last-named a personal deity, limited in power, exists side by side with a multitude of intellectual beings, who existed before the formation of the world in a chaotic state as absolutely isolated individuals. The process of world formation begins with the decision of the divine Spirit to bring a harmony of the cosmos out of these many existences. Though Spencer's influence in philosophical development was not so great in Germany as in England, the idea of development has continued in recent years to exert no little power. Space forbids more than a mention of Lotze's teleological idealism; Von Hartmann's absolute monism, in which the goal of the teleological development of the universe is the reversion of the will into not-willing; Wundt's metaphysics of the will, according to which the world is a development, an eternal becoming, in which nature is a preliminary stage to mind; and Nietzsche's individualism, the final point of which is the development of the superman.
V. Relation to Modern Theology:
When the Darwinian hypothesis was first broached in Great Britain and America it caused nothing less than a panic in nearly all circles of religious thought. The fear was that if it was true it must result in the transformation of all religious values. Here and there it was indeed advocated by distinguished scientists and theologians in the interests of faith, but it was for the most part met by fierce and prolonged opposition. The following beliefs became the center of interest and have remained such until the present day. (1) The Biblical account of the creation : whether it had a beginning; whether God was the Creator, or the world was eternally in process of becoming; further, whether the Genesis story could be harmonized with geology, astronomy, biology, archeology, and other sciences. (2) The Biblical account of man; whether he was wholly and immediately created by God, or, even if his body was organically related to the animal world, his mind was a direct creation, or finally, whether both body and mind shared in the development from lower forms of life. (3) Concerning man's personal history: whether he began in a state of "original righteousness" from which he fell only to be recovered by a miraculous intervention, or started low down, at the outset scarcely to be distinguished from the highest existing animal consciousness. (4) Involved in man's personal history was a profound modification of the origin and development of the idea of God from the lowest fetishism or animism through polytheism to ethical monotheism (see COMPARATIVE RELIGION, VI., 1), of the idea of the Scriptures as not inerrant and infallible, but as recording the stages through which man's consciousness has passed in its apprehension of the ethical and religious meaning of life, and of the entire range of Christian beliefsprovidence, sin and evil, the person and work of Christ, the Christian life, the Church, and the future. A similar change of values has occurred in other regions of thought. (5) In psychology and ethics (q.v.) the static has given place to the genetic and historic point of view. (6) In apologetics (q.v.) for the traditional conception of prophecy as predictive and miracles as out of relation to natural law has been substituted the spiritual and dynamic doctrine of man and the world. (7) The philosophy of religion has found in comparative religion the key to its interpretation of religion as a fact of universal human experience. (8) While the uniqueness of Christianity is recognizednow more than ever beforeits organic relation to pre-Christian types of experience is the subject of exhaustive inquiry and its development as a system of beliefs, institutions, and ideals becomes more clearly evident to students of its history.
Since evolution as a scientific theory is only a method according to which at any given period existing conditions have come into being, it does not primarily concern the grounds of reality. It is atheistic only when as a philosophy it reduces the world-ground to a system of mechanical necessity (see ATHEISM). When, however, the ultimate reality is conceived as a power realizing rational ends in the universe, evolution is affirmed as the uniform method by which this power fulfils its purposes (cf. B. P. Bowne, Theism, New York, 1902).
C. A. B.