But even this is not all that can be said as to the fluctuating character of that fundamental material quality "inertia." It appears possible, if electrons approach too near each other, so as to encroach on each other's magnetic field as they move, that then their inertia may fall in value during the time they are contiguous. No experimental fact has yet suggested this at present: it is improbable that even in the tightest combinations they ever really approach close enough to each other to make the effect appreciable in the slightest degree; still, strictly speaking, the inertia of matter is a known mathematical function of the distance of electrons apart, compared with their size, as well as of their absolute speed through the ether; and hence it may be found to vary from either of two distinct reasons. Nevertheless, even this variation would not be expressed as a failure in the conservation of matter, though there is now no single material property that can be specified as really and genuinely constant. So long as the electric centres of strain, or whatever they are—so long as the electric charges themselves—continue unaltered, we should prefer to say that at least the basis of matter was fundamentally conserved.
Further than this, however, we cannot go; and to say, as Professor Haeckel says, that the modern physicist has grown so accustomed to the conservation of matter that he is unable to conceive the contrary, is simply untrue. Whatever may be the case in real fact, there is no question with respect to the possibility of conception. The electrons themselves must be explained somehow; and the only surmise which at present holds the field is that they are knots or twists or vortices, or some sort of either static or kinetic modification, of the ether of space—a small bit partitioned off from the rest and individualised by reason of this identifying peculiarity. It may be that these knots cannot be untied, these twists undone, these vortices broken up; it may be that neither artificially nor spontaneously are they ever in the slightest degree changed. It may be so, but we do not know; and it is quite easy to conceive them broken up, the identity of the electron lost, its substance resolved into the original ether, without parts or individual properties. If this happened, within our ken, we should have to confess that the properties of matter were gone, and that hence everything that could by any stretch of language be called "matter" was destroyed, since no identifying property remained. The discovery of such an event may lie in the science of the future; it would be an epoch-making event in the history of science, but no physicist would be upset by it—perhaps not even surprised; nor would any one have good reason to be astonished if the correlative phenomenon occurred, and under certain conditions some knots or strains were some day caused in the ether, which had not been previously there; and so "matter," or the foundation of matter, artificially produced. In other words, the destruction and the creation of matter are well within the range of scientific conception, and may be within the realm of experimental possibility.
Persistence of the Existent.
Is there, then, no meaning in the conception which Professor Haeckel and others have so enthusiastically formulated, and which certainly commends itself to every one as representing in some sense a genuine truth, whether it be called a "law of substance" or whatever it be called? There does seem a certain plausibility in the idea, pure guess or assumption though it be, that anything which really and fundamentally exists, in a serious and untrivial and non-accidental sense, can be trusted not suddenly to go out of existence and leave no trace behind. In other words, there seems some reason to suppose that anything which actually exists must be in some way or other perpetual; that real existence is not a capricious and changing attribute: arbitrary collocations and accidental relations may and must be temporary, but there may be in each a 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.