A criticism of Hume's Tenth and Eleventh sections occupies a long note appended by Lord Brougham to his "Discourse on Natural Theology"—a volume I suppose accessible to almost all students of the science.
[77] The word Creation must here be construed strictly, so as to signify a true Beginning;—the idea that is of a law-governed materies mundi, a substantial force, and movement evoked into primary Existence.
The prospect of final change yet to be, is thus similarly connected by a living philosopher (Helmholtz) with the history of our world's Past:—
"We estimate the duration of human History at 6,000 years; but immeasurable as this time may appear to us, what is it in comparison with the time during which the earth carried successive series of rank plants and mighty animals, and no men; during which in our neighbourhood the amber-tree bloomed, and dropped its costly gum on the earth and in the sea; when in Siberia, Europe, and North America groves of tropical palms flourished; where gigantic lizards, and after them elephants, whose mighty remains we still find buried in the earth, found a home? Different geologists, proceeding from different premises, have sought to estimate the duration of the above-named creative period, and vary from a million to nine million years.——The time during which the earth generated organic beings is again small when compared with the ages during which the world was a ball of fused rocks. For the duration of its cooling from 2,000° to 200° Centigrade the experiments of Bishop upon basalt show that about 350 millions of years would be necessary.——And with regard to the time during which the first nebulous mass condensed into our planetary system, our most daring conjectures must cease. The history of man, therefore, is but a short ripple in the ocean of time.——For a much longer series of years than that during which he has already occupied this world, the existence of the present state of inorganic nature favourable to the duration of man seems to be secured, so that for ourselves and for long generations after us we have nothing to fear. But the same forces of air and water, and of the volcanic interior, which produced former geological revolutions, and buried one series of living forms after another, act still upon the earth's crust. They more probably will bring about the last day of the human race than those distant cosmical alterations of which we have spoken, forcing us perhaps to make way for new and more complete living forms, as the lizards and the mammoth have given place to us and our fellow-creatures which now exist.
"Thus the thread which was spun in darkness by those who sought a perpetual motion has conducted us to a universal law of nature, which radiates light into the distant nights of the beginning and of the end of the history of the universe. To our own race it permits a long but not an endless existence; it threatens it with a day of judgment, the dawn of which is still happily obscured. As each of us singly must endure the thought of his death, the race must endure the same. But above the forms of life gone by, the human race has higher moral problems before it, the bearer of which it is, and in the completion of which it fulfils its destiny." Helmholtz, Popular Lectures on Scientific Subjects, p. 191, seq.
The distinguished German had just before observed, "Even though the force store of our planetary system is so immensely great ... still the inexorable laws of mechanics indicate that this store of force, which can only suffer loss and not gain, must be finally exhausted." On the subject of such vast cosmical changes, the reader may like to peruse the remarks of Littré in his most recent volume—"Les choses, ou, pour mieux dire, nos choses sont d'hier, dût cet hier comporter de prodigieuses durées.
"Cette nouveauté est un témoignage que notre monde, notre univers, auront une fin. Ce qui a commencé doit finir, la raison le dit, et toutes nos connaissances physiques le confirment. Le soleil et les étoiles se refroidissent incessamment, versant dans les espaces une chaleur qui ne leur revient jamais. Quelque chauds qu'ils soient, ils le sont chaque jour un peu moins, le calorique s'y épuisera; ils s'éteindront, comme déjà leurs planètes se sont éteintes. Que deviendront ces masses animées d'un mouvement rapide? Nul ne peut le dire. Mais il suffirait d'un choc entre elles pour y transformer un prodigieux mouvement en une prodigieuse incandescence, et y renouveler un cycle de chaleur et d'expansion.
"Ce serait se perdre en vaines et gratuites hypothèses, que de spéculer sur ce que deviendra notre univers quand il aura pris fin, comme de spéculer sur ce qu'il fut avant qu'il eût pris commencement." Littré, La Science, pp. 560, 1.
There are thinkers who believe that these cycles, immeasurable to Man, took their governing laws from a supreme Designer. They will be aided by Helmholtz and Littré in shaping their ideas of His far-reaching wisdom and power. There are also thinkers who find within their own inward Being a consciousness of kinship with the Source of Causation, so infinitely beyond cycles apparently infinite. How great then the value of human Spirits bearing His likeness, and with it a promise of surviving the period when our world's cycles shall vanish away in Space—to be replaced by other hereditary cycles, or to be remembered no more for ever!
[78] This article has been lately reprinted in a volume of "Critiques and Addresses," and Leibniz's censure of Newton will be found on p. 323. It may be convenient for some readers to be informed that the Correspondence between Clarke and Leibniz to which I have referred will be found at the end of Erdmann's Opera Leibnitii (Berlin, 1840), a portable and useful Edition. The sentences quoted by me are on page 747.