We are now in a position to examine with more precision the extremely important laws of nervous action which are involved in the phenomena designated by the terms Reflex Action, Automatic Action, and Voluntary Action.
“L’organisme le plus complexe est un vaste mécanisme qui résulte de l’assemblage de mécanismes secondaires.”--CLAUDE BERNARD.
“Les corps vivants sont machines à l’infini.”--LEIBNITZ.
“Noi lamentiamo con Majendie che nel linguaggio fisiologico siensi intruse le preopinioni psicologiche col trascico inevitabile del vocaboli, ai quali codeste preopinioni si trovano legate. Probabilmente questa fu una delle principali cagioni degli errori e degli equivoci anatomofisiologici, da cui non poterono svincolarsi, a loro insaputa, i cultori sperimentali della scienza, perchè nell’ interpretare i fenomeni osservati erano obbligati ad usare il linguaggio di una false moneta in corso.”--LUSSANA _e_ LEMOIGNE, _Fisiologia dei Centri Nervosi_, 1871, I. 16.
1. Modern Philosophy has moved along two increasingly divergent lines. One, traversed by Galileo, Descartes, Newton, and Laplace, had for its goal the absolute disengagement of the physical from the mental, i. e. the objective from the subjective aspect of phenomena, so that the physical universe, thus freed from all the complexities of Feeling, might be interpreted in mechanical terms. As a preliminary simplification of the problem this was indispensable; only by it could the First Notion of primitive speculation be replaced by the Theoretic Conception of scientific speculation.[204] The early thinker inevitably invested all external objects with properties and qualities similar to those he assigned to human beings, and their actions he assigned to human motives. Sun, moon, and stars seemed living beings; flames, streams, and winds were supposed to be moved by feelings such as those known to move animals and men. Nor was any other conception then possible: men could only interpret the unknown by the known, and their standard of all action was necessarily drawn from their own actions. Not having analyzed Volition and Emotion, above all not having localized these in a neuro-muscular system, men could not suspect that the movements of planets and plants, and of streams and stones, had motors of a different kind from the movements of animals. The scientific conception of inert insensible Matter was only attained through a long education in abstraction; and is assuredly never attained by animals, or by savages. But no sooner were vital conditions recognized, than the difference between vital and mechanical movements emerged. When men learned that many of their own actions were unaccompanied either by Love or Hate, by Pleasure or Pain, and that many were unprompted by conscious intention, while others were unaccompanied by conscious sensation, they easily concluded that wherever the special conditions of Feeling were absent, the actions must have some other motors. Intelligence, Emotion, Volition, and Sensation being one by one stripped away from all but a particular class of bodies, nothing remained for the other bodies but insensible Matter and Motion. This was the Theoretic Conception which science substituted for the First Notion. It was aided by the observation of the misleading tendency of interpreting physical phenomena by the human standard, substituting our fancies in the place of facts, manipulating the order of the universe according to our imagination of what it might be, or ought to be. Hence the vigilance of the new school in suppressing everything pertaining to the subjective aspect of phenomena, and the insistance on a purely objective classification, so that by this means we might attain to a knowledge of things as they are. By thus withdrawing Life and Mind from Nature, and regarding the universe solely in the light of Motion and the laws of Motion, two great scientific ends were furthered, namely, a classification of conceptions, and a precision of terms. Objective phenomena made a class apart, and the great aim of research was to find a mathematical expression for all varieties under this class. Masses were conceived as aggregates of Atoms, and these were reduced to mathematical points. Forces were only different modes of Motion. All the numberless differences which perception recognized as _qualities_ in things, were reduced to mere variations in _quantity_. Thus all that was particular and concrete became resolved by analysis into what was general and abstract. The Cosmos then only presented a problem of Mechanics.