members. The theory of evolution, by its doctrine of the hereditary transmission of acquired modifications, gives a scientific basis for this existing solidarity between man and society.

The great consensus of opinion amongst those who are best qualified to judge-amongst those who alone are qualified to judge-may be regarded as having established the claim of the theory of evolution to give the most satisfactory account of all forms of natural life. And it may seem only advancing the theory a step further, or only developing one of its applications, to make it yield a complete explanation of human nature, mental as well as physical. If ethics, then, is to be founded on a "natural" basis, no theory would seem to be complete which leaves evolution out of account.

In general, the theory of evolution is an assertion of the unity of life, or, in its widest form, of the unity of existence. Progressive modifications and hereditary transmission of such modifications are, it is contended, sufficient to explain the different forms and species which life now manifests. The assumption is specially discarded that there are fixed differences between kinds of living things making it impossible for them all to have developed from simple germs, originally of like constitution, which have, in the course of time, become more heterogeneous and complex, and so given rise to the wealth of organic life. But this general doc

an assertion

of the unity

of life;

in first instance, historical;

trine, held (wholly or in part) in modern times by Kant, Wolff, and Lamarck, needed to be supplemented by a definite view of the way in which the progressive modifications took place; and this required to be established as a really operative cause, before evolution could receive scientific proof. This more special element of the theory was Darwin's contribution to the subject. Evolution, he showed, and herein consists his theoretical advance on Lamarck,-has taken place by the "natural selection" of organisms, so modified as to fit them for survival in the struggle for existence. Organisms in which advantageous modifications have been produced tend to survive, and to transmit their modified structure to descendants, while organisms in which such modifications have not been produced, are less able to preserve their life and to hand it on to successors. Older types, it is true, remain, but only in circumstances in which their continued existence does not seriously interfere with the organisms which, in the struggle for life, have developed a structure better suited to their environment: when more perfect and less perfect forms cannot exist together, only the better adapted survive.

The theory of evolution is thus primarily the history of an order of sequent facts and relations. It is an account of the origin or growth of things, which attempts to explain their nature and consti

a teleological aspect,

have ethical

quences.

人

tution by showing how they have come to be what they are. But, in so doing, it naturally reveals the method and tendency of this order. And it is by but implies means of this its teleological aspect that we see how it may be possible for it not merely to trace the de- which may velopment of historical facts, such as the feelings conseand customs of men, but at the same time to make a more real contribution to ethics by pointing out the course of action to which human nature is adapted. It does not, like the old teleology, attempt to show that each thing has been formed with the design of subserving some particular purpose. On the contrary, it reverses this way of looking at things. The fitness of an organism to fulfil any definite end comes to be regarded as the result not of a conscious design, independent of the environment, but of the modifications produced on the organism through the necessity laid upon it by its surroundings of adapting itself to them or else disappearing. What the theory does show is, that adaptation to environment is necessary for life, and that organisms unable to adapt themselves pass away. Adaptation to environment will thus be implied in, or be an essential means towards, selfpreservation and race-preservation, self-development and race-development. And should this preservation or development be looked upon as the end of conduct, the adaptation to environment it implies may help to define and characterise the end.

Again when an organism adapts itself to its environment, it does so by some modification being produced in its structure corresponding to the modified function required by the conditions of life. In this way, one organism increases in complexity in a certain direction, while another organism, in different circumstances, also develops a more complicated structure, though one of a different kind. Thus organisms, alike to begin with, become heterogeneous in nature through exposure to different surroundings. At the same time, by constant interaction with their environments, they become more definite and coherent in structure. Incipient modifications are developed and defined in different ways by different circumstances, and the parts of a living being are brought into closer reciprocal relations, and thus welded into a coherent organic whole. This is what Mr Spencer means when he says that evolution implies a transition from “an indefinite incoherent homogeneity to a definite coherent heterogeneity":1 the whole process being interconnected in such a way that these different aspects of it-definiteness, coherence, heterogeneity -increase together and imply one another. By this the inference would appear to be suggested that, if conduct is to harmonise with the conditions of evolution, this characteristic feature of it must be recognised in the ethical end.

1 First Principles, 4th ed., p. 380.

of its historical and

aspects.

In saying this, I am perhaps anticipating results. Distinction But it is well to show at the outset how the essentially historical inquiry carried out by the evolu- ethical tionists may suggest conclusions which are ethical in their nature. To some, indeed, it will appear superfluous to have spent even a sentence in suggesting a prima facie case for the ethical importance of evolution. If there is one subject more than another, it may be thought, which has secured a place for itself in the scientific consciousness of the day, it is the evolution-theory of ethics. Without question, the phrase has been received into the scientific vocabulary; but there is a good deal, even in the official literature on the question, to make one doubt whether it is always used with a distinct conception of its meaning. When reference is made to the "ethics of evolution," no more is sometimes meant-though a great deal more should be meant -than an historical account of the growth of moral ideas and customs, which may provide (as Mr Stephen expresses it) " a new armoury wherewith to encounter certain plausible objections of the so-called Intuitionists." This, however, would only affect the ethical psychology of an opposed school. The profounder question still remains, What bearing has the theory of evolution, or its historical psychology and sociology, on the nature of the ethical end, or on the standard for distinguishing right and wrong in conduct? The answer to this question

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