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Darwin (Erasmus) professes the same theory, substituting for the word vibration' the expression sensorial movements.' Although his system is full of absurd hypotheses,' he has the merit of seeing that psychology is subordinate to the laws of life, and of cutting short ill-put questions and factitious problems. Why with two eyes do we see objects single? Why, the images being reversed upon the retina, do we see objects straight ? These questions and those of the same kind are psychological, and cannot be resolved either by optics or anatomy. We might as well deduce the assimilation of sugar from the angles of its crystals, as deduce the perception of an object from the laws of optics ; sugar must be dissolved before being assimilated, and so the retinal images must be transformed by the sensational centre, before affecting the brain. And this is not a gratuitous hypothesis, it is sustained by facts. It can be demonstrated. We see objects single with our two eyes, but we also hear sounds as single with our two ears ; our two nostrils give us a single scent; our five fingers give us objects as single. These facts have a bearing upon one another, and they demand reflection. Their explanation ought to be psychological, and I think, says Mr. Lewes, that it is very simple. Here it is :
'I believe the explanation to be very simple. We cannot have two precisely similar sensations at precisely the same instant; the simultaneousness of the two sensations renders them indistinguishable. Two sounds of precisely the same pitch and intensity, succeeding each other by an appreciable interval, will be heard as two sounds; but if they succeed each other so rapidly that the interval is inappreciable, no distinction will be felt, and the two will be heard as one, because heard simultaneously. . . . The various Sensational Centres are variously affected by the same stimuli : electricity giving to the gustatory nerve the stimulus of savorous bodies, to the auditory nerve the stimulus of sonorous vibrations, to the optic nerve the stimulus of luminous bodies, to the tactile nerves the stimulus of touch. .. Nor is this all : narcotics introduced into the blood excite in each Sensational Centre the
1 Ibid. vol. ii. p. 358.
specific sensation normally excited by its external stimuli. ... From these indubitable facts it is not difficult to elicit a conclusion, namely, that sensation depends on the Sensational Centre, and not on the external stimulus, . . . and there the impression first becomes a sensation. . . . When therefore it is asked, Why do we see objects erect, when they throw inverted images on the retina ? the answer is,—Because we do not see the retinal image at all ; we see, or are affected by, the object; and our perception of the erectness of that object does not depend on vision, but on our conceptions of space and the relations of space, which are not given in the visual sensation.' 1
The Scotch school is summarily treated ;although its psychology contains much available matter for students, it is entirely dead as a doctrine. It is dead, and it deserved to die, because it had no object and no true method. It has added verbal analysis to verbal analysis, metaphysical explanation to metaphysical explanation ; whilst physiologists and some psychologists were going to the bottom of things.
Those to whom this allusion is made appear to be Cabanis and Gall.
The mention of the name of Cabanis immediately recalls the famous 'secretion of thought.' By an unhappy phrase, says Mr. Lewes,3 Cabanis has given the advantage to his adversaries, and has prevented the progress of his own doctrines. He has been understood to have said that the brain secretes thought as the liver secretes bile. He never said anything of the sort. It is true that by a deplorable ambiguity of language he may lead us to interpret him as holding that thought is a secretion, while in reality he meant to say that it is a function. Certainly, if he did regard thought as a secretion, the error was monstrous, and the outcry against him was justifiable.'' But the truth is, that he, like many biologists and psychologists, had very obscure ideas upon function. His great merit has been clear perception of the relations of psychology to the science of life, and the recognition of a great truth, already clearly seen by Aristotle, and thus expressed by St. Thomas Aquinas : 'Impossibile est in uno homine esse plures animas per essentiam differentes, sed una tantum est anima intellectiva quæ vegetativo et sensitivo et intellectivo officiis fungitur.'
Lewes, History of Philosophy, vol. ii. p. 359-361. 2 Ibid. p. 393.
3 Ibid. p. 375. 4 For the text of the phrase, see Cabanis, Rapports du Physique et du Moral, ed. Peisse, p. 138, with a note by the editor, who does not take it seriously.
• History of Philosophy, vol. ii. p. 376.
Gall is treated with fulness and favour in pages 394 to 435 ; Mr. Lewes attributes to him one merit, that of having rendered service to physiology and to psychology even by the daring of his hypotheses; and two defects, that of completely neglecting subjective analysis in psychology, and of having founded a phrenology or cranioscopy belied by facts and the progress of science.
If Gall has been accused of materialism, it has been wrongfully, because he has several times declared that he 'confines himself to phenomena,' and that he has never comprised in his researches anything relating to the essence of the body, or of the soul. “I do not understand,' he says, 'that our faculties are a product of organization, because this would be to confound the conditions with the efficient causes.' It may be said that Gall has put a definite end to the dispute between the partisans of innate ideas, and the doctrine of sensation, by showing that there are innate tendencies, as much affective as intellectual, which belong to the organic structure of man. Two psychological facts, already vaguely perceived, have been brought out by him :
1. The fundamental tendencies are innate, and cannot be created by education.
11. The various faculties are essentially distinct and independent, though intimately united among themselves.
He has also clearly seen and clearly expressed that the greatest obstacle to the progress of psychological researches is to isolate man from the animal series, and to consider him as governed by totally special organic laws.
He has understood that psychology, being a branch of biology,
1 Mr. Lewes, quoting in p. 648 an analogous expression of Vogt's, manifests his distaste to phrases made for effect, aiming at terrifying, and which he calls 'pistol-shots.'
and consequently subject to all the biological laws, must be studied according to biological methods. Zoological, anatomical, philosophical, and pathological observations, all these are necessary as a basis: and certainly Gall has amassed more facts of this sort than any of his predecessors; he has exhibited the patience and the skill of an investigator, although he may have drawn from all his collection of materials false interpretations and unverified conclusions. But there is another very important instrument of research, which Gall has omitted ; this is subjective analysis; an instrument so necessary that several psychologists, neglecting the importance of biological researches, maintain that psychology ought to be erected into a distinct science, and founded upon that analysis. Hence the weakness of the psychological classifications of Gall, Spurzheim, and George Combe has rendered them rather more acceptable, but no one has had the faintest conception of what psychological analysis ought to be, of its means, of its conditions, and of the problems which it has to solve. How are we to determine whether a mental manifestation is the direct product of a faculty, or the indirect product of two or more faculties? How are we to distinguish between faculties and modes, between elementary actions and associated actions, between energies and synergies? These are very important questions, which no one has tried to solve. Gall attributes to us twenty-seven faculties, among which are those of veneration, of individuality, of colour, of eventuality, and many others which evidently are not at all original faculties. His doctrine is thus very weak on this point. Nevertheless, the great principle of Kant, that we must seek in the laws of thought a solution of philosophical problems, Gall has had the merit of approaching on the biological side.
"We ought to seek our ideas and our knowledge partly in the phenomena of the exterior world, and in their rational employment, and partly in the innate laws of the moral and intellectual faculties.' 1
Physiologically he takes his revenge. His novelty consists in his precision. The relations between the physical and the moral
1 Gall, Functions of the Brain, i. 84.
nature had been vaguely recognised; also general relations of the nervous system and the mental functions; but none had ever attempted a precise demonstration of them. Many facts were known, such as the following : the toothache, which disappears when we reach the dentist's door ; taking water, fancying that it is an emetic, and vomiting in consequence. These facts were explained by attributing them to the imagination. That is well; but by what material conditions did imagination act upon the viscera or upon the tooth? These simple-minded explanations supposed a sort of autocratic imagination, without feeling any necessity of discovering a particular mechanism for the production of the results. Gall has not succeeded in discovering one, but at least he has seen that it was necessary to substitute precise ideas for the vague generalities then current. Phrenology or cranioscopy had this aim; it assigned each part of the cerebral mass as the seat of one particular faculty. But this hypothesis had to be confronted with facts, and it was found to be false. The most eminent neurologists declared against it, so that now phrenology finds itself in the rear of the discoveries of physiology, without having ever succeeded in constituting its psychology.
We have not to follow Mr. Lewes in his explanation of German philosophy, nor in his criticism on Auguste Comte. Here, however, there is one point which we must notice. We know that Stuart Mill has keenly criticised the omission of psychology in the classification of the sciences, such as is admitted by the positive school.1 Mr. Lewes replies to this criticism by the following distinction : If it is a question of recognising that psychology is a possible science, and of great value, that subjective analysis has been misunderstood by Comte, and that he has done wrong in regarding internal observation as an illusory process, I agree with Mr. Mill. But if it is a question of recognising in psychology an independent science, separate from biology, and to assign it a place of its own in the hierarchy of abstract sciences, then I am with M. Comte. Psychology may be a concrete
1 On this point see Littré, Auguste Comte et Stuart Mill, and two articles in the Revue des Deux Mondes, on La Philosophie positive, September and November 1867.