SPONTANEITY. the name for the doctrine, referring to the human mind, that mus cular action may, and does, arise from purely internal causes, and independent of tho stimulus of It had long been the tacit assumption in mental philosophy, that we are never moved to action of any kind, except under the stimulation of some feeling, some pleasure or pain, or some end in view. To this is now opposed the doc trine of the spontaneous commencement of movements under certain circumstances; which, however, does not exclude, but only supplements, the operation of the feelings in stitnulatinz movements, as in the ordinary course of voluntary action. The doctrine supposes that the nerve-centers, after repose and nourishment, acquire a fulness of vital energy, which discharges itself in the play of movement, without any other occasion or motive; the addition of a feeling, or end, enhances and directs the activity, but does not wholly create it.
Of the various proofs and illustrations of spontaneity, perhaps the most striking is that furnished by the movements of young animals of the active species. A young dog or kitten shows a degree of activity out of all proportion to any feeling to be gratified, or any end to be served; we can interpret it only as internal energy seeking vent, irre tpective of the pursuit of pleasure or the avoidance of pain—in other words, the action of the will. When the accumulated energy is expended, the animal fails back into a
%tate of repose, and is then roused only by the stimulus of sensation. The state called "freshness" in a horse, for example, is a state of superabundant and irrespresible activity. Children go through the same phase: after rest or confinement, they burst. forth incontinently into some form of active excitement, of which a part may be con sidered as pure spontaneity, while part may be owing to sensation.
The doctrine is well fitted to express the difference between the active and the sensi tive temperaments; for if it were true that actions is in proportion to the stimulation of the feelings, the most susceptible characters would be the most active. But, in point of fact, the active temperament is manifested by a profusion of activity for its own sake, with little circumspection or regard to consequences; and constitutes the restless, bust ling, roughshod, energetic, and enterprising disposition of mind, as seen in sportsmen, soldiers, travelers, etc.
The explanation of the growth of the will (q.v.), or voluntary power, involves the spontaneous beginning of movements.—See Bain on The Senses and the Intellect, 2d edit., p. 76.