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.