fundamental substratum which, if it can be reached, will be found to be eternal. I develop this idea further in the sequel. This is, at any rate, what Professor Haeckel was evidently groping after, as many others have groped before him, and the nature of this fundamental persistent entity or entities (for we must not assume without proof that there is only one: there may be several, and at any rate their ultimate unification may be a still further advanced and more transcendental problem) may with some appropriateness be called 'the problem of the universe,' since it is clearly the problem of existence. Professor Haeckel thinks he has solved the problem, grasped the fundamental reality, and found it to be matter and energy and nothing else; though why he chooses to regard matter and energy as one thing instead of two is not perfectly plain to me, nor, I venture to say, is it really plain to him.

Making the assumption, then, that there is something, or that there are several things, to be discovered, which may thus have the most fundamental property, viz., persistent immutable existence, the 'problem' has resolved itself into the discovery of what these things actually are. It will not do to jump at some object and assume that that is it.

A multitude of things obviously perish, thereby showing themselves to be trivial or accidental arrangements, according to our hypothesis. A flame is extinguished and dies, a mountain is ultimately ground into sand by the slow influence of denudation, a planet or a sun may lose its identity by encounter with other bodies. All these are temporary collocations of atoms; and it appears now that an atom may break up into electric charges, and these again may some day be found capable of resolving themselves into pristine ether. If so, then these also are temporary, and in the material universe it is the ether only which persists—the Ether with such states of motion or strain as it eternally possesses—in which case the Ether will have proved itself the material substratum and most fundamental known entity on that side.

But are we to conclude, therefore, that nothing else exists? that the existence of one thing disproves the existence of others? The contention would be absurd. The category of life has not been touched in anything we have said so far; no relation has been established between life and energy, or between life and ether. The nature of life is unknown. Is life also a thing of which constancy can be asserted? When it disappears from a material environment is it knocked out of existence, or is it merely transferred to some other surroundings, becoming as difficult to identify and recognise as are the gases of a burnt manuscript or the vapour of a vanished cloud? Is it a temporary trivial collocation associated with certain complex groupings of the atoms of matter, and resolved into nothingness when that grouping is interfered with? or is it something immaterial and itself fundamental, something which uses these collocations of matter in order to display itself amid material surroundings, but is otherwise essentially independent of them? (This idea is expanded in Chapters VI. to X., and see note at end of present chapter.)

Professor Haeckel would answer this question with a contemptuous negative; and the treatment which he would thus give to life he would also extend to mind and consciousness, to affection, to art, to poetry, to religion, and all the other facts of experience to which in the process of evolution humanity has risen: I say he would answer the question, whether these had any real existence other than as a necessary concomitant of a sufficiently complex material aggregate, with a contemptuous negative; but I challenge him to say by what right he gives that answer. His speculation is that all these properties are nascent and latent in the material atoms themselves, that these have the potentiality of life and choice and consciousness, which we perceive in their developed combinations. As a speculation this is legitimate; but the only answer that can by science legitimately be given at the present time is the answer given by du Bois-Reymond, ignoramus, we do not know.

Scientifically we do not; and for a man of science to pretend, or to assert in a popular treatise, that we do, is essentially and seriously to mislead. (See Chapter VII. below.) It may even be a question whether the assertion of entire ignorance at the present time is completely appropriate, whether we have not some positive evidence against Professor Haeckel's contention. I believe that we have; and though I may acquiesce in an assertion of present ignorance, I am not at all willing to accept the next sentence of Professor du Bois-Reymond's answer, and to say ignorabimus, we never shall know.

The matter seems to me within the legitimate lines of scientific inquiry, and it is unwise to attempt prediction, especially negative prediction, or to attempt to close the door to the future developments of knowledge.

But I am content to say for the present that from the point of view of strict science it is not yet possible to give any positive answer to these questions; that they must await the progress of discovery. It becomes a question of some interest, therefore, how it is possible for Professor Haeckel and for others of his school to have arrived at the idea not only that a scientific answer can be given, but that already it has been given, and that they know distinctly what it is.

Note on the Word "Life."

Until a term is accurately defined, and even afterwards for some purposes, it is permissible to use a word of large significance in more than one sense. Thus the word "light" may be considered a psychological term, denoting a certain sensation, or a physiological term, signifying the stimulus of certain specialised nerve-endings, or a physical term, expressing briefly an electromagnetic wave-disturbance in the ether. I am using the word "life" in a quite general sense, as is obvious, for if it be limited to certain metabolic processes in protoplasm—which is the narrowest of its legitimate meanings—what I have said about its possible existence apart from matter would be absurd. It may be convenient to employ the word "vitality" for this limited sense; but so far as I know, there is no general consensus of usage, and the context must suffice to show a friendly reader the connotation intended.

CHAPTER III

THE DEVELOPMENT OF LIFE

This leads me to the second main thesis or central scientific doctrine of Professor Haeckel's treatise, the biological one; and it is this which I shall now proceed to illustrate by further quotations, viz., the connection as he conceives it between life and matter.

His view is that life has arisen from inorganic matter without antecedent life. The experimental facts of biogenesis he discards in favour of a hypothetical and at present undiscovered kind of spontaneous generation. He assumes that the chemico-physical properties of carbon confer so peculiar a power on its albuminoid compounds that they develop into living protoplasm. He says that he formulated this view thirty-three years ago, and that no better monistic theory has arisen to replace it, while to reject some form of spontaneous generation is to admit a miracle:—