Note at — Chapter V

The problem awaiting the philosophic physicist runs as follows:—

It remains to be seen how closely and with what degree of distinctness, science can approximate these impalpable forces governing the natural world, to the forces we are accustomed to call immaterial, because they become known to us by the activities of Thought and Will.

This problem—the incorporeity of Matter, or a near approach to it—has been a favourite subject of speculation in all ages. The curious reader may track it from the pre-and post-Christian Greeks through Arabian and Jewish philosophies to the Schoolmen (who borrowed from Jews unknowingly) and so transmitted it down like an heirloom to our own later controversialists. The subject has been treated on Metaphysical grounds, for Religious interests, or as a weapon keen edged in demolishing antagonistic cosmologies. But it has not often been entertained for purely scientific reasons, and as one of those so-called "useless questions" which always turn out most prolific seminal principles, fertile in explaining nature and throwing out branches in numerous unforeseen directions.

It was thus however and with no side views that the illustrious Faraday looked at this subject. With what effect may be best learned by putting together two separate accounts of his reasoning.

In 1844, Dr. Bence Jones informs us Faraday (then in his 53rd year) indulged in "A speculation respecting that view of the nature of matter which considers its ultimate atoms as centres of force, and not as so many little bodies surrounded by forces.... The particle, indeed, is supposed to exist only by these forces, and where they are it is."

This speculation did in fact give a tone to that memorable season—now thirty years ago.

Dr. Tyndall says:—"On Friday, January 19, 1844, he opened the weekly evening meetings of the Royal Institution by a discourse entitled 'A speculation touching Electric Conduction and the nature of Matter.' In this discourse he not only attempts the overthrow of Dalton's Theory of Atoms, but also the subversion of all ordinary scientific ideas regarding the nature and relations of Matter and Force. He objected to the use of the term atom:—'I have not yet found a mind,' he says, 'that did habitually separate it from its accompanying temptations; and there can be no doubt that the words definite proportions, equivalent, primes, etc., which did and do fully express all the facts of what is usually called the atomic theory in chemistry, were dismissed because they were not expressive enough, and did not say all that was in the mind of him who used the word atom in their stead,'" (Faraday as a Discoverer, pp. 119-20.)

And again:—"With his usual courage and sincerity he pushes his view to its utmost consequences. 'This view of the constitution of matter,' he continues, 'would seem to involve necessarily the conclusion that matter fills all space, or at least all space to which gravitation extends; for gravitation is a property of matter dependent on a certain force, and it is this force which constitutes the matter. In that view matter is not merely mutually penetrable; but each atom extends, so to say, throughout the whole of the solar system, yet always retaining its own centre of force.'" Faraday "compares the interpenetration of two atoms to the coalescence of two distinct waves, which though for a moment blended to a single mass, preserve their individuality, and afterwards separate." (Ibid. pp. 123-4 and note.)

The subject did not easily lose its hold on the philosopher's mind. "At the Institution," writes Dr. Bence Jones, "he gave eight lectures after Easter on the phenomena and philosophy of heat. He ended this course thus:—'We know nothing about matter but its forces—nothing in the creation but the effect of these forces; further our sensations and perceptions are not fitted to carry us; all the rest, which we may conceive we know, is only imagination.' He gave two Friday discourses: the first on the nature of matter, the other on recent improvements in the silvering of mirrors.

"His notes of the first lecture begin thus:—'Speculations dangerous temptations; generally avoid them; but a time to speculate as well as to refrain, all depends upon the temper of the mind. I was led to consider the nature of space in relation to electric conduction, and so of matter, i.e. whether continuous or consisting of particles with intervening space, according to its supposed constitution. Consider this point, remarking the assumptions everywhere.

"'Chemical considerations abundant, but almost all assumption. Easy to speak of atomic proportions, multiple proportions, isomeric and isomorphic phenomena and compound bases; and to account for effects we have only to hang on to assumed atoms the properties or arrangement of properties assumed to be sufficient for the purpose. But the fundamental and main facts are expressed by the term definite proportion,—the rest, including the atomic notion, is assumption.

"'The view that physical chemistry necessarily takes of atoms is now very large and complicated; first many elementary atoms—next compound and complicated atoms. System within system, like the starry heavens, may be right—but may be all wrong. Thus see how little of general theory of matter is known as fact, and how much is assumption.

"'Final brooding impression, that particles are only centres of force; that the force or forces constitute the matter; that therefore there is no space between the particles distinct from the particles of matter; that they touch each other just as much in gases as in liquids or solids; and that they are materially penetrable, probably even to their very centres. That, for instance, water is not two particles of oxygen side by side, but two spheres of power mutually penetrated, and the centres even coinciding.'" Bence Jones—Life of Faraday, Vol. II., pp. 177-78.

These views (best known as Boscovich's theory), though not generally held in scientific circles, are favoured by Bacon's most able commentator, Robert Leslie Ellis, and are pronounced by Professor Huxley a "tenable hypothesis." Mr. Spencer poises the balance as follows:—"Though the combining weights of the respective elements are termed by chemists their 'equivalents,' for the purpose of avoiding a questionable assumption, we are unable to think of the combination of such definite weights, without supposing it to take place between definite numbers of definite particles. And thus it would appear that the Newtonian view is at any rate preferable to that of Boscovich. A disciple of Boscovich, however, may reply that his master's theory is involved in that of Newton; and cannot indeed be escaped. 'What,' he may ask, 'is it that holds together the parts of these ultimate atoms?' 'A cohesive force,' his opponent must answer. 'And what,' he may continue, 'is it that holds together the parts of any fragments, into which, by sufficient force, an ultimate atom might be broken?' Again the answer must be—a cohesive force. 'And what,' he may still ask, 'if the ultimate atom were, as we can imagine it to be, reduced to parts as small in proportion to it, as it is in proportion to a tangible mass of matter—what must give each part the ability to sustain itself, and to occupy space?' Still there is no answer but—a cohesive force. Carry the process in thought as far as we may, until the extension of the parts is less than can be imagined, we still cannot escape the admission of forces by which the extension is upheld; and we can find no limit until we arrive at the conception of centres of force without any extension." First Principles, p. 54.

It is evident that Faraday was able to think in a manner which has been often declared impossible. Mr. Spencer's statement of the counter case is alone sufficient to prove that the inquiry is sure to be recurrent. We may add with Dr. Tyndall that facts alone cannot satisfy the mind, and that when a law is established, the question "why" is inevitable. Compare foot-note p. 324 post.