The Principles of Psychology, Vols. 1-2

Similarly, the increased wariness of the large birds, of those on islands frequented by men, of the woodcock, of the foxes, may be due to the fact that the bolder families have been killed off, and left none but the naturally timid behind, or simply to the individual experience of older birds being imparted by example to the young so that a new educational tradition has occurred. — The cases of physical refinement, nervous temperament, Yankee type, etc., also need much more discriminating treatment than they have yet received from the Lamarckians. There is no real evidence that physical refinement and nervosity tend to accumulate from generation to generation in aristocratic or intellectual families ; nor is there any that the change in that direction which Europeans transplanted to America undergo is not all completed in the first generation of children bred on our soil. To my mind, the facts all point that way. Similarly the better breathing of the greyhounds born in Mexico was surely due to a post-natal adaptation of the pups' thorax to the rarer air.

Distinct neurotic degeneration may undoubtedly accumulate from parent to child, and as the parent usually in this case grows worse by his own irregular habits of life, the temptation lies near to ascribe the child's deterioration to this cause. This, again, is a hasty conclusion. For neurotic degeneration is unquestionably a disease whose original causes are unknown ; and like other * accidental variations * it is hereditary. But it ultimately ends in sterility ; and it seems to me quite unfair to draw any conclusions from its natural history in favor of the transmission of acquired peculiarities. Nor does the degeneration of the children of alcoholics prove anything in favor of their having inherited the shattered nervous system which the alcohol has induced in their parents : because the poison usually has a chance to directly affect their own bodies before birth, by acting on the germinal matter from which they are formed whilst it is still nourished by the alcoholized blood of the parent. In many cases, moreover, the parental alcoholics are themselves degenerates neurotically, and the drink-habit is only a symptom of their disease, which in some form or other they also propagate to their children.

There remain the inherited mutilations of the guineapig. But these are such startling exceptions to the ordinary rule with animals that they should hardly be used as examples of a typical process. The docility of domestic cattle is certainly in part due to man's selection, etc., etc. In a word, the proofs form rather a beggarly array. Add to this that the writers who have tried to carry out the theory of transmitted habit with any detail are always obliged somewhere to admit inexplicable variation. Thus Spencer allows that

" Sociality can begin only where, through some slight variation, there is less tendency than usual for the individuals to disperse. . . . That slight variations of mental nature, sufficient to initiate this process, may be fairly assumed, all our domestic animals show us: differences in their characters and likings are conspicuous. Sociality having thus commenced, and survival of the fittest tending ever to maintain and increase it, it will be further strengthened by the inherited effects of habit.'* Again, in writing of the pleasure of pity, Mr. Spencer says : " This feeling is not one that has arisen through the inherited effects of experiences, but belongs to a quite different group, traceable to the survival of the fittest simply — to the natural selection of incidental variations. In this group are included all the bodily appetites, together with those simpler instincts, sexual and parental, by which every race is maintained ; and which must exist before the higher processes of mental evolution can commence." +

The inheritance of tricks of manner and trifling peculi^ arities, such as handwriting, certain odd gestures when pleased, peculiar movements during sleep, etc., have also been quoted in favor of the theory of transmission of acquired habits. Strangely enough ; for of all things in the world these tricks seem most like idiosyncratic variations. They are usually defects or oddities which the education of the individual, the pressure of what is really acquired by him, would counteract, but which are too native to be repressed, and breaks through all artificial barriers, in his children as well as in himself.

I leave my text practically just as it was written in 1885. I proceeded at that time to draw a tentative conclusion to the effect that the origin of most of our instincts must certainly be deemed fruits of the back-door method of genesis, and not of ancestral experience in the proper meaning of the term. Whether acquired ancestral habits played any part at all in their production was still an open question in which it would be as rash to affirm as to deny. Already before that time, however. Professor Weismann of Freiburg had begun a very serious attack upon the Lamarckian theory,"^ and his polemic has at last excited such a widespread interest among naturalists that the whilom almost unhesitatingly accepted theory seems almost on the point of being abandoned.

I will therefore add some of Weismann's criticisms of the supposed evidence to my own. In the first place, he has a captivating theory of descent of his own,t which makes him think it a priori impossible that any peculiarity acquired during lifetime by the parent should be transmitted to the germ. Into the nature of that theory this is not the place to go. Suffice to say that it has made him a keener critic of Lamarck's and Spencer's theory than he otherwise might have been. The only way in which the germinal products can be influenced whilst in the body of the parent is, accord-

* Ueber die Vererbung (Jena, 1883). Prof. Weismann's Essays on Heredity have recently (1889) been published in English in a collected form, f Best expressed in the Essay on the ContinuitcU des Keimplasmas (1885). ing to Weismann, by good or bad nutrition. Through this they may degenerate in various ways or lose vitality altogether. They may also be infected through the blood by small-pox, syphilis, or other virulent diseases, and otherwise be poisoned. But peculiarities of neural structure and habit in the parents ivhich the parents themselves were not horn tdthy they can never acquire unless perhaps accidentally through some coincidental variation of their own. Accidental variations develop of course into idiosyncrasies which tend to pass to later generations in virtue of the well-known law which no one doubts.

Eeferriug to the often-heard assertion that the increase of talent found in certain families from one generation to another is due to the transmitted effects of exercise of the faculty concerned (the Bachs, the Bernoullis, Mozart, etc.), he sensibly remarks, that the talent being kept in exercise, it ought to have gone on growing for an indefinite number of generations. As a matter of fact, it quickly reaches a maximum, and then we hear no more of it, which is what happens always when an idiosyncrasy is exposed to the effects of miscellaneous intermarriage.

The hereditary epilepsy and other degenerations of the operated guinea-pigs are explained by Professor Weismann as results of infection of the young by the parent's blood. The latter he supposes to undergo a pathologic change in consequence of the original traumatic injury. The obsolescence of disused organs he explains very satisfactorily, without invoking any transmission of the direct effects of disuse, by his theory of panmixy, for which I must refer to his own writings. Finally, he criticises searchingly the stories we occasionally hear of inherited mutilations in animals (dogs' ears and tails, etc.), and cites a prolonged series of experiments of his own on mice, which he bred for many generations, cutting off both parental tails each time, without interfering in the least with the length of tail with which the young continued to be born.

The strongest argument, after all, in favor of the La- marckian theory remains the a priori one urged by Spencer in his little work (much the solidest thing, by the way, which lie has ever written) * The Factors of Organic Evolution.' Since, says Mr. Spencer, the accidental variations of all parts of the body are independent of each other, if the entire organization of animals were due to such accidental variations alone, the amount of mutual adaptation and harmony that we now find there could hardly possibly have come about in any finite time. We must rather suppose that the divers varying parts brought the other parts into harmony with themselves by exercising them ad hoc, and that the effects of the exercise remained and were passed on to the young. This forms, of course, a gresii presumption against the all-sufficiency of the view of selection of accidental variations exclusively. But it must be admitted that in favor of the contrary view, that adaptive changes are inherited, we have as yet perhaps not one single unequivocal item of positive proof.

I must therefore end this chapter on the genesis of our mental structure by reaffirming my conviction that the socalled Experience-philosophy has failed to prove its point. No more if we take ancestral experiences into account than if we limit ourselves to those of the individual after birth, can we believe that the couplings of terms within the mind are simple copies of corresponding couplings impressed upon it by the environment. This indeed is true of a small part of our cognitions. But so far as logical and mathematical, ethical, sesthetical, and metaphysical propositions go, such an assertion is not only untrue but altogether unintelligible; for these propositions say nothing about the time- and space-order of things, and it is hard to understand how such shallow and vague accounts of them as Mill's and Spencer's could ever have been given by thinking men.

The causes of our mental structure are doubtless natural, and connected, like all our other peculiarities, with those of our nervous structure. Our interests, our tendencies of attention, our motor impulses, the aesthetic, moral, and theoretic combinations we delight in, the extent of our power of apprehending schemes of relation, just like the elementary relations themselves, time, space, difference and similarity, and the elementary kinds of feeling, have all

grown up in ways of wMcli at present we can give no account. Even in the clearest parts of Psychology our insight is insignificant enough. And the more sincerely one seeks to trace the actual course of psychogenesiSy the steps by which as a race we may have come by the peculiar mental attributes which we poi^isess, the more clearly one perceives " the slowly gathering twilight close in utter night, " Authors the titles only of whose works are cited are not, as a rule, referred to in this index.

Adaptation of mind to environmeiio results in our knowing the impressing circumstances, 625 ff. Alteration of one impression by another one simultaneously taking place, II. 28 ff., 201 A priori connections exist only between objects of perception and 'ovements, not between sensory iaeas, II. 581. A priori ideas and experience. Chapter XXVIII. A pi'iori propositions, II. 661-5 Association, Chapter XIV: is not of ideas, but of things thought of,

action-time, 427-84; accompanied by feelings of tension due to adaptation of sense-organs, 434-8; involves imagination or preperception of object, 438-44; conceivable as a mere effect, 448 ff. Babe and candle, scheme of, I. 25 Baby's first perception, II. 8, 34; his Brain, its functions. Chapter II: of frog, I. 14; of dog, 33; of monkey, 34; of man, 36; lower centres compared with hemispheres, 9-10, 75; circulation in, 97; instability, 139; its connection with Mind, 176; 'entire' brain not a real physical fact, 176; its changes as subtle as those of thought, 234; its dying vibrations operative in producing consciousness, 242

Comparison, Chapter XIII: relations discovered by comparison have nothing to do with the time and space order of their terms, II. 641; mediate, 489, 644; see difference, likeness Composition, of Mind out of its elements, see Mind-Stuff theory; differences due to, I. 491 Difference, not resolvable into composition, I. 490 ; noticed most between species of a genus, 529 ; the magnitude of, 531; least discernible, 537 ff.; methods for ascertaining, 540 ff .

Discrimination, Chapter XIII; conditions which favor it, I. 494; improves by practice, 508; spatial, II. 167 ff. See difference Duration, the primitive object in time-perception, I. 609; our estimate of short, 611 ff. Emotion, Chapter XXV: continuous with instinct, II. 442; description of typical emotions, 443-9; results from reflex effects of stimulus upon organism, 449 ff . ; their classification, 454; in anaesthetic subjects, 455; in the absence of normal stimulus, 458-60; effects of expressing, 463 ff . ; of repressing, 466; the subtler, 469 ff.; the neural process in, 472; differences in individuals, 474; evolution of special emotions, 477 ff.

Essences, their meaning, II. 329 ff . ; sentimental and mechanical, 665 Frog's nerve-centres, I. 14 Fusion of feelings unintelligible, General propositions, what they involve, II. 337 ff. See universal conceptions Habits may inhibit instincts, II. 394. Habit accounts for one large part of our knowledge. 632 Hereditary transmission of acquired characters, see inheritance Human intellect, compared with that of brute, II. 348 ff.; depends on association by similarity, 9ad ££.; various orders of, 860;

Ideal objects, eternal and necessary relations between, II. 639, 661. See conception Identity, personal, I. 288, 330 ff.; based on ordinary judgment of sameness, 384; due to resemblance and continuity of our feelings, 336; Lotzeon, 350; only relatively true, 373 Imagination, Chapter XVIII: it differs in individuals, II. 51 ff.; sometimes leaves an after-image, 67; the cerebral process of, 68 ff.; not locally distinct from that of sensation, 73; \& figured, 82

' Integration ' of feelings, Spencer's theory of, I. 151 ff. Lange, L., on reaction-time, muscular and sensorial, I. 92 Memory, Chapter XVI : it depends on material conditions, I. 2; th« essential function of the hemispheres, 20; lapses of, 373 ff., in hysterics, 384 ff.; favored by attention, 427; primary, 638, 643; analysis of the phenomenon of Memor^^, 648; the return of a mental image is not memory, 649; memory's causes, 653 ff. ; the result of association, 654; conditions of good memory, 659; brute retentiveness, 660; multiple associations, 662; improvement of memory, 667 ff . ; its usefulness depends on forgetting much, 680; its decay, 683; metaphysical explanations of it, 687 ff.

Mercier, C, on inertness of consciousness, 135; on inhibition, II. Mind, depends on brain-conditions, I. 4, 553 ; the mark of its presence, 8; difficulty of stating its connection with brain, 176; what psychology means by it, Movement, perception of, by sensory surfaces, II. 171 ff.; part played by, in vision, 197,203,234-7 the. Production of. Chap. XXII requires guiding sensations, 490 illusory perception of, during anaesthesia, 489; results from every kind of consciousness, 526

Nature, the order of, its incogru ence with that of our thought, II. 634 ff . Necessary truths are all truths of comparison, II. 641 fi., 651, 662. ^QQ experience, a priori connections, etc. Partiality of mind, see interest, teleology, intelligence, selection, essences Past time, known in a present feeling, I. 627; the immediate past is a portion of the present duration-block, 608 ff. Perceptlou, Chapter XIX : compared with sensation, II. 1, 76;

ff. Possession, Spirit-, I. 393 ff. Post-hypnotic suggestion, II. 613 Practical interests, their effects on Problematic conceptions, I. 468 Problems, the process of solution Reaction-time, I. 87; simple, 88; what it measures is not conscious thought, 90; Lange's distincliou between muscular and sensorial, 92; its variations, 94-7; influenced by expectant attention, 427 ff.; after intellectual process, 432; after discrimination, 523; after association, 557; after perception, II. 131

Reality, the Perception of. Chapter XXI; not a distinct content of consciousness, 286; various orders of, 287 ff. ; every object has some kind of reality, 291 ff . ; the choice of, 290; practical, 293 ff.; means relation to the self, 295-8; relation of sensations to, 299; of emotions, Reasoning, Chapter XXII; its definition, II. 325; involves the picking out of essences, or sagacity, 329, and abstraction, 332; its utility depends on the peculiar constitution of this world, 337 ff., 651; depends on association by similarity, 345

Reflex acts, I. 12; reaction-time measures one, 90; concatenated habits are constituted by a chain of, 116 Retinal sensibility, see mmn, space, identical points, third dimension, projection, etc. Beat of consciousness, I. 65; of Soul, 214; of sensations, no original, Sciences, the natural, the factors of their production, II. 633 ff.; a Turkish cadi upon, 640; postulate things with unchangeable properties, 666 Sciences, the pure, they express results of comparison exclusively, II. 641; classifications, 646; logic, 647; mathematics, 653

Self, consciousness of. Chap. X; not primary, I. 273; the empirical self, I. 291; its constituents, 292; the material self, 292; the social self, 293; the spiritual self, 296; resolvable into feelings localized in head, 300 ff.; consciousness of personal identity, 330 ff.; its alterations, 373 ff. Self-love, I. 317; the name for ac tive impulses and emotions to wards certain objects ; we do not love our bare principle of indi viduality, 323 Sensation, does attention increase its strength? I. 425; terminus of thought, 471

from perception, II. 1, 76; its cog nitivc function, 3; pure sensation an abstraction, 3; the terminus of thought, 7 Soul, theory of the, I. 180; inaccessibility of, 187; its essence is to think (according to Descartes), 200; seat of, 214; arguments for its existence, 343 ff. ; an unnecessary hypothesis for psychology, 350; compared with transcendental Ego, 365; a relating principle, Space, the perception of, Chapter XX; primitive extensity in three dimensions, II. 134-9; spatial order, 145; space-relations, 148; localization in, 153 ff.; how real apace is mentally constructed, 166 S. ; part played by movement in, 171-6; measurement of extensions, 177 ff.; synthesis of originally chaotic sensations of extension, 181 ff.; part played by articular surfaces in, 189 ff.; by muscles, 197 ff.; how the blind i^erceive space, 203 ff.; visual ipace, 211-268; theory of identical points, 222; of projection, 228; difficulties of sensation-theory expounded and replied to, 231- 268; historical sketch of opinion, 270 ff.

Speech, the ' centre * of, I. 55; its misleading influence in psychology, I. 194; thought possible without it, 269. See Aphasia, Phrenology Stream of Thought, Chapter IX: scheraratic representations of, I. Substitution of parts for wholes in reasoning, II. 330; of the same for the same, 650 Succession, not known by successive feelings, I. 628; vs. duration, Thought, synonym for consciousness at large, I. 186; the stream of. Chapter IX: it tends to personal form, 225; same thought never comes twice, 231 ff.; sense in which it is continuous, 237; can be carried on in any terms, 260-8; what constitutes its rational character, 269; is cognitive, 271; not made up of parts, 276 ff., II. 79 ff . ; always partial to some of its objects, I. 284 ff . ; the consciousness of it as a process, 300 ff. ; the present thought is the thinker, 369, 401; depends on material conditions. 553 Thought readmg,' II. 636

Time, occupied by neural and mental processes, see reaction-time Time, the perception of, Chapter XV; begins with duration, I. 609; compared with perception of space, 610 ff.; empty time not perceived, 619; its discrete flow, 621, 637; long intervals conceived symbolically, 622 ff.; variations in our estimate of its length, 623 ff.; cerebral process underlying, 627 ff. Unconscious states of Mind, proofs of their existence, I. 164 ff.' Ob- jections, 164 ff.