As an episode in this somewhat abstract discussion, it may be diverting to notice the question of priority of discovery, touched upon in the following note (p. 454): “Until I recently consulted his ‘Outlines of Astronomy’ on another question, I was not aware that, so far back as 1833, Sir John Herschel had enunciated the doctrine that ‘the sun’s rays are the ultimate source of almost every motion which takes place on the surface of the earth.’ He expressly includes all geologic, meteorologic, and vital actions; as also those which we produce by the combustion of coal. The late George Stephenson appears to have been wrongly credited with this last idea.”
In order to add to the thorough discussion of this important question, we wish to suggest the claims of Thomas Carlyle, who, as far back as 1830, wrote the following passage in his Sartor Resartus (Am. ed. pp. 55-6): “Well sang the Hebrew Psalmist: ‘If I take the wings of the morning, and dwell in the uttermost parts of the Universe, God is there.’ Thou, too, O cultivated reader, who too probably art no psalmist, but a prosaist, knowing God only by tradition, knowest thou any corner of the world where at least force is not? The drop which thou shakest from thy wet hand, rests not where it falls, but to-morrow thou findest it swept away; already, on the wings of the north wind, it is nearing the tropic of Cancer. How it came to evaporate and not lie motionless? Thinkest thou there is aught motionless, without force, and dead?
“As I rode through the Schwartzwald, I said to myself: That little fire which glows starlike across the dark-growing (nachtende) moor, where the sooty smith bends over his anvil, and thou hopest to replace thy lost horseshoe—is it a detached, separated speck, cut off from the whole universe, or indissolubly joined to the whole? Thou fool, that smithy-fire was primarily kindled at the sun; is fed by air that circulates from beyond Noah’s deluge, from beyond the Dog star; it is a little ganglion, or nervous centre in the great vital system of immensity.”
We have, finally, to consider the correlation theory in connection with equilibrium.
I. Motion results from destroyed equilibrium. The whole totality does not correspond to itself, its ideal and real contradict each other. The movement is the restoring of the equilibrium, or the bringing into unity of the ideal and real. To illustrate: a spring (made of steel, rubber, or any elastic material) has a certain form in which, it may exist without tension; this may be called the ideal shape, or simply the ideal. If the spring is forced to assume another shape, its real shape becomes different from the ideal; its equilibrium is destroyed, and force is manifested as a tendency to restore the equilibrium (or unity of the ideal and real). Generalize this: all forces have the same nature; (a) expansive forces arise from the ideal existing without—a gas, steam, for example, ideally takes up a more extended space than it has really; it expands to fill it. Or (b) contractive forces: the multiplicity ideally exists within; e. g. attraction of gravitation; matter trying to find the centre of the earth, its ideal. The will acts in this way: The ideal is changed first, and draws the real after it. I first destroy, in thought and will, the identity of ideal and real; the tension resulting is force. Thinking, since it deals with the universal (or the potential and the actual) is an original source of force, and, as will result in the sequel from a reverse analysis (see below, V. 3, c) the only source of force.
II. Persistence of force requires an unrestorable equilibrium; in moving to restore one equilibrium, it must destroy another—its equivalent.
III. But this contradicts the above developed conception of force as follows: (a) Since force results from destroyed equilibrium, it follows (b) that it requires as much force to destroy the equilibrium as is developed in the restoring of it (and this notion is the basis of the correlation theory). But (c) if the first equilibrium (already destroyed) can only be restored by the destroying of another equal to the same, it has already formed an equilibrium with the second, and the occasion of the motion is removed.
If two forces are equal and opposed, which will give way?
By this dialectic consideration of force, we learn the insufficiency of the theory of correlation as the ultimate truth. Instead of being “the sole truth, which transcends experience by underlying it” (p. 258), we are obliged to confess that this “persistence of force” rests on the category of causality; its thin disguise consists in the substitution of other words for the metaphysical expression, “Every effect must be equal to its cause.” And this, when tortured in the crucible, confesses that the only efficient cause is “causi sui;” hence the effect is equal to its cause, because it is the cause.
And the correlation theory results in showing that force cannot be, unless self-originated.