INTRODUCTION.

§1. I PROPOSE in the following pages to give the chief conclusions reached by Modern Science on the central questions of religion, morals, and society,-to state, in a word, the general creed of Science; and, as the scientific faith may still be fallible, or of unequal degrees of credit, I propose, in the second place, to offer some comments and criticisms on some of its more doubtful articles, with a view to their reconsideration or revision.

Already many have taken in hand to set forth the scientific faith, together with the grounds on which it rests. In particular, eminent physicists and naturalists both in this country and in Germany-Huxley, Clifford, Tyndall, Haeckel, Helmholtz, Tait, and Balfour Stewart have all attempted it in essays, addresses, or books, with more or less pretence at fulness. But the physicists and naturalists, though they may be depended upon to reflect accurately the tendency of scientific thought on the questions within their respective provinces which touch on the sphere of religion, do not speak with the same authority on questions moral, social, or philosophical.

The scientific thinkers, to whom the work more properly belongs, have also attempted to give expositions of scientific faith and doctrine. Within the past forty years Comte, Mill, Strauss, and Herbert Spencer have all essayed it. But as the two former wrote before the discovery of the two most comprehensive generalizations in physics and biology-the law of the Conservation of Energy and the law of Natural Selection-they failed to reach the new and more commanding point of view which these two laws place henceforth at the disposal of thinkers. Their systems are accordingly to a considerable extent superseded as incomplete scientific explanations of the universe, while the moral and social doctrines of both are pronounced by Herbert Spencer inconsistent with the deepest and widest generalizations of the laws of life and society.

Herbert Spencer has himself, in the various volumes of his new system of evolution-philosophy, given the most complete and philosophic statement of the scientific faith, and he has given it with special references to the above-named. highest laws. But waiving the fact that physicists object to some of his physics, and philosophers to some of his philosophy, the system is itself so voluminous and vast-in fact, so severe a course of reading, which postulates a special facility in the art of quickly apprehending the meaning of a train of abstract symbols, scientific and philosophic-that a more compendious if not an easier exposition would seem a matter to be desired. To supply some such condensed exposition to the large and increasing class who have an intelligent human interest in the new scientific theories, and in the great collision and controversy now going on between the new and old beliefs is one object of this book; to supplement the exposition with a criticism which may

assist them to separate the false from the true elements in the new creed, is the second and possibly more important object.

§ 2. In the absence of any single and universally acknowledged authority on all articles of faith and doctrine I have taken the consensus of scientific opinion amongst the few highest authorities on each particular article, and I have treated this as the orthodox teaching of Science-as what would have been the decision had all such authorities met together in Council to fix the faith. Thus, on the question of the origin and future dissolution of our earth and solar system, the most eminent physicists are in the main agreed, however much they may differ on such philosophical questions as the immortality of the Soul or the existence of God. Professors Tait and Helmholtz, for example, differing on the latter, are still agreed that a widely dispersed nebulous matter, closing together under gravitation, awoke the sun's fires, and produced the earth and planets originally at molten heat. They are further agreed, and so also are Professors Balfour Stewart and Clifford, in accepting Sir W. Thomson's doctrine of the Dissipation of Energy with the consequent future dissolution of all the systems of the universe. There is a consensus of opinion, that is to say, amongst the foremost physicists as to the remote physical beginning and far-off end of the material universe, though they differ widely as to the nature and destiny of the human soul. Accordingly, this consensus of opinion may be accounted an article of scientific faith, even though some physicists seem disposed to doubt it.

In like manner, I have treated as the orthodox belief the Darwinian doctrine of the origin of Species, and in particular

of the animal origin of Man, even though there still exists with respect to both an eminent body of scientific dissent. It is to be so held because the balance of biological authority, estimated not less in quality than in quantity, has clearly pronounced in its favour; and because on these two points the biologists form the final court of appeal.

But when we come to mental, moral, and social questions, neither physicists nor naturalists are any longer authorities, however little some of them seem disposed to concede the point. In particular, when the question relates to man and his behaviour under the complex motive forces, conscious or unconscious, which determine it (supposing the question to come at all within the range of scientific methods or treatment), we shall no longer refer to the physicist or the naturalist for the scientific doctrine. Not to the physicist certainly, whose special studies of the invariable behaviour of matter or the settled sequences of physical phenomena prepare him very imperfectly for the investigation of the widely different phenomena presented by human conduct; nor yet to the naturalist, whose infinitely wider subject of plant and animal life forbids the due concentration of regard upon the special human subject, particularly on its inner conscious side. Nor need we greatly care as yet to consult that new man of science, the anthropologist,-not at least until he has a little more systematized the miscellaneous mass of facts referring to man in all times and climes which at present forms the subject-matter of his study.

On all questions concerning man himself, his virtues and vices, and the uniformity, such as it is, which his life in society presents, we are properly referred, on the part of science, to a different order of specialists-to the psychologist, the moralist, the sociologist, to such authorities as Mill, or

Bain, or Herbert Spencer, who, in addition to their writings on the philosophy or the logic of the sciences, have dealt expressly, and from the scientific point of view, with ethical and social questions. It is true, indeed, that both physical and vital phenomena are manifested in the human subject, that man is both a machine and an organism in which the law of the transmutation of energy is fulfilled; true, therefore, that he is so far a proper subject for physical and biological investigation; still, neither the most important nor the most interesting problems presented by man relate to the mechanism, however express and admirable, of his physical structure, nor to the transmutations of physical into vital and mental energy which really has place within the human machine. Nor do they relate to those other facts of organic functions and their various relations, with which the science of physiology deals. The most important problems presented by man from the point of view of science are psychological, moral, and social, and our scientific authorities may be credited with having taken into consideration such physical and physiological conclusions as have special and important bearing on these questions.

§ 3. Thus far on the subject of authorities. But it may be said, If your exposition be unexceptionable, and your finding of faith and doctrine accurately gathered from the first and surest sources as respects each particular article, is it not a little presumptuous to affect thereafter to criticise such acknowledged authorities?

I think not, and for the following reasons:-In the first place, we must distinguish between scientific faith and scientific fact, between a fully verified law and a supposed inference hazarded from it without being contained