Evolution

Evolution. 1. In Algebra or Arithmetic, is the inverse process of involution (q.v.), and as such requires a primary knowledge of the latter. Its manipulation is either effected directly by systematic guess-work, known as the process of square-root, cube-root, and the like, or indirectly by the same through the medium of logarithms. But the latter being applicable only to known numbers, can be used in arithmetical evolution only; nevertheless, its general applicability in solving any root whether integral or fractional renders it highly useful.

2. A theory which regards all higher or more complex forms of existence as following and depending on lower and simpler forms - the cause of this gradual transition being immanent in the lower form of existence which is thus transformed. It is thus an attempt to solve one of the two main problems of philosophy. The first of these problems is the ultimate nature of reality, or mind and matter in relation to one another, the statical aspect of the world: the second, which evolution attacks, is the dynamical question of becoming, how have things become what they are, and how are they now being changed. As a cosmogony (q.v.) evolution conflicts, at least partially, with the theory of emanation, which had an Oriental origin and was developed by the Neoplatonists, Gnostics, Arab philosophers and Cabalists, and with that of direct creation by a personal deity.

The foundation of the modern mechanical conception of nature and of physical evolution was laid by Descartes; added to by Leibnitz's theory of sentient monads; illustrated from the history of human progress by Pascal, Priestley, and Lessing; applied to the heavens by Kant and Laplace; and to the whole of nature and mind by Schelling and Hegel. The theory of descent or the derivative origin of existing species of plants and animals practically dates from the works of Lamarck and Treviranus in the first decade of the present century - neither Erasmus Darwin nor Goethe having essentially strengthened the position of the theory as more than a poetic fancy. The authority of Cuvier retarded the acceptance of the theory by biologists; but after the middle of the century many independent lines of research outside the field of biology prepared the way for its firm establishment.

Experiments on the mechanical production of heat and the chemical production of electricity led to the generalisation of the conservation of energy. The work of Black and Lavoisier in demonstrating the indestructibility of matter was extended by means of the spectroscope in the hands of Kirchhoff, Bunsen, Huggins, and others to the showing that the chemical elements of the heavenly bodies are the same as those of our earth. The same process of observation gave a firmer footing of fact to the nebular hypothesis of Kant and Laplace. The use of fossils by William Smith as indicating succession among sedimentary rocks, the restoration of these extinct forms of life by Cuvier and other palaeontologists, and the insistence by Hutton, Playfair, and Lyell on the sufficiency of existing physical agencies to explain the facts of geology, called attention to the immensity of the age of the earth and to its having been successively inhabited by races of plants and animals different from, and in many respects lower than, those now living. The discoveries of McEnery and Boucher de Perthes in bone-caves and river-gravels conclusively established the great antiquity of man (q.v.) on the earth, and suggested his advance in culture from the most helpless barbarism; and the application of the comparative method to the study of languages prepared the minds of scholars for similar conclusions.

Cuvier had shown biologists the existence of fundamental types of structure in groups adapted to varied modes of life and the "serial homology" of parts, such as the limbs of animals and the leaves of plants, modified for distinct functions; and Von Baer's (q.v.) parallel between the development of the individual and that of the race had shown the bearing of embryology (q.v.). When, in 1858, Darwin (q.v.) and Wallace brought forward the principle of natural selection as the mode of organic evolution, Mr. Herbert Spencer had already elaborated a consistent philosophy of evolution in which this principle readily found its place. In the Origin of Species the facts of the geographical distribution of organisms and of the existence of rudimentary or vestigiate structures were set forth in their true bearing- on the general theory; and, so far as biology is concerned, the result of the last 30 years' investigations has been to make every biologist an evolutionist, though the relative importance of the principle of natural selection, of the influence of the environment (q.v.), and of other processes, in the production and preservation of varieties is still a matter of dispute.

Darwin suggests an ethical extension of his views in defining the general good as "the rearing of the greatest number of individuals in full health and vigour and with all their faculties perfect under the conditions to which they are subject," and Mr. Spencer similarly looks on human progress as a gradual process of self-adaptation of man to his environment - i.e. of increasing happiness. [Darwinism, Development, Environment, Mimicry, Natural Selection, etc.]