Thought

I myself am inclined to hold that man really thinks very little and very seldom.—Wilhelm Wundt

§ 61. The Nature of Thought.—“The train of thoughts, or mental discourse,” wrote Hobbes in 1651, “is of two sorts. The first is unguided, without design, and inconstant; in which case the thoughts are said to wander, and seem impertinent one to another, as in a dream. The second is more constant; as being regulated by some desire, and design: and because the end, by the greatness of the impression, comes often to mind, in case our thoughts begin to wander, they are quickly again reduced into the way.” Hobbes is here distinguishing, so far as unaided observation allows him, between the mental connections that reflect a random play of the associative tendencies, and those whose course is directed by some determining tendency. The former, to be sure, are never wholly random; ideas are grouped together by the situation in which they appear (p. 165); and it is only fair to say that Hobbes himself, in other passages, recognises this guidance. There is, nevertheless, a marked difference between the two kinds of ‘mental discourse,’ between (say) the casual flow of conversation and the working out of an argument; and it is the second kind, the progressive movement of ideas towards an end, that modern psychology has technically named thought.

You notice that we have spoken of a ‘progressive’ movement; and you notice that Hobbes writes a little cautiously of regulated discourse; even in that, our thoughts may ‘begin to wander,’ These are merely different ways of saying that thought goes on in the state of secondary attention; it is an experience of the same general type as recollection, constructive imagination, selective and volitional action. We therefore ‘think,’ in the technical sense, far less often than the popular use of the word would suggest. For, on the one hand, we accept a great many judgements, ready made, from our surroundings; parents and teachers and friends are constantly expressing opinions which we adopt without question, opinions which they themselves have adopted, for the most part, in the same unquestioning way. The present generation takes the motor-car and the air-ship for granted; it finds them natural and obvious; and every generation falls heir to a body of social, political, religious, Æsthetic, and moral judgements which also seem natural and obvious; thought is not needed, and so is rarely undertaken. Secondly, even if we are obliged to think, we still tend to think no further than is necessary for the practice of life; we attain a certain level of thought, in the mastery of our business or profession, and there stop; the pattern of secondary attention is replaced by that of derived primary attention. Most of our thought, in other words, is either borrowed thought or routine thought, that is, is not (in the psychological sense) thought at all; independent, sustained, original thinking is as rare as creative imagination or as sagacious and farsighted action. In all probability, it always has been rare; our ancestors probably thought as we think, only a few with real seriousness, and they only between whiles; but a very little thinking gives man an immense superiority over the lower animals!

We have now to ask, first, about the terms in which thought goes on; and we shall find that it may go on in imaginal complexes, in words, and in mental attitudes. We then discuss the pattern of thought; and we shall find that thinking is characterised by the ‘division into pairs’ which we mentioned on p. 205. Lastly, we shall take up, separately, some of the special features of this general pattern.

§ 62. Imaginal Processes in Thought: The Abstract Idea.—A great deal of controversy has raged about the abstract or general idea. We can see to-day that the name is, psychologically, a misnomer. Just as no idea is, in its own right, an idea of memory or of imagination, so also no idea is, in its own right, an abstract idea; an idea becomes, is made into, an abstract idea whenever its context and determination carry the meaning of abstractness and generality. The associationists, however, looked at things differently; they thought that any idea which means ‘abstract’ must also itself be abstract; and so they distinguished a special class of abstract ideas. We obtain such ideas, they said, in this way: we review a large number of particular ideas, and we separate out the elements that are common to all of them; this common remainder is then a general or abstract idea which represents the whole group of particulars. Thus, “by leaving out of the particular colours perceived by sense that which distinguishes them one from another; and retaining that only which is common to all; the mind makes an idea of colour in abstract which is neither red, nor blue, nor white, nor any other determinate colour.”

An emphatic protest was raised against this theory by the idealistic philosopher George Berkeley (1685-1753). “The idea of man that I frame to myself must be either of a white or a black or a tawny, a straight or a crooked, a tall or a low or a middle-sized man. I cannot by any effort of thought conceive [that is, mentally picture] the abstract idea above described.” It is, truly, a little difficult to imagine an abstract ‘colour’ with all the specific colour-elements left out! Yet the theory is so plausible, as long as process and meaning are confused, that it has been revived again, though in somewhat altered form. The suggestion has been made that an abstract idea is a sort of composite photograph, a mental picture which results from the superposition of many particular perceptions or ideas, and which therefore shows the common elements distinct and the individual elements blurred. A passage from Huxley illustrates this view. “An anatomist who occupies himself intently with the examination of several specimens of some new kind of animal, in course of time acquires so vivid a conception of its form and structure, that the idea may take visible shape and become a sort of waking dream. But the figure which thus presents itself is generic, not specific. It is no copy of any one specimen, but, more or less, a mean of the series.” To which we reply that ‘the figure which presents itself’ is as specific and particular as any other idea; only, it means the genus; the anatomist is working under the suggestion of a type, of a composite picture that will make a diagram in a text-book or monograph; and his idea is abstract in virtue of this determination and context, and not because it pictures the mean of a series.

The fact is, to repeat, that any idea is made into an abstract idea when context and determination carry the meaning of abstractness; and there is no doubt that, in minds of a certain type, imaginal processes other than words may take on this context and suffer this determination, so that thought may go on in imaginal terms. Experiments show that visual imagery may play its part, along with verbal ideas and attitudes, in a single train of thought; one recent writer describes visual images of a complex kind as centres of ‘activity’ in the progress of thinking. Blindfold chess-players, if they are of the motor type, think of attack and defence in terms of ‘lines of force’ which connect the various pieces on the board, and which they themselves ‘feel’ in kinÆsthetic imagery as pushes and pulls in hand and arm. We saw on p. 77 that such general notions as ‘virtue’ and ‘commerce’ may come to mind in the form of habitual images. No doubt, these images were at first contextual processes surrounding a verbal idea; they are therefore secondary, and not original; yet they may now replace the verbal idea, and do duty by themselves as abstract ideas. There are probably a good many of us whose abstract idea of ‘triangle’ is simply a mental picture of the little equilateral triangle that stands for the word in text-books of geometry.

Is there, then, no truth at all in the theory of the composite photograph? Not an atom, so far as regards the genesis of the abstract idea; one might superpose individual ideas ad infinitum, and one would still have nothing more than an individual idea. But if we leave the abstract idea out of the question, and consider the history of ideas, in minds of the imaginal type, then the composite photograph has more to say for itself. For we know from p. 156 that the associative tendencies, if left to themselves, gradually die out; and that the weaker die out more quickly than the stronger. Consider what this means! I have a mental picture of a landscape, and I do not see the actual scene for some years. The picture fades out; but it fades out unevenly; its various features are correlated with associative tendencies of varying strength. So I shall always imagine a semicircle of mountains with the valley opening towards me, and the river meandering down the valley; for these are features common to many landscapes and strongly impressed upon my nervous system; but I shall lose the relative heights of the mountains, and the particular turns of the river, and the special distribution of villages and churches; for these are individual features, and have been less frequently repeated. My mental picture of the landscape thus approaches a type; and the same thing is true of all complex images, if they are left to themselves, and the underlying associative tendencies decay from old age. These typical images are, nevertheless, ideas of particular scenes or things or faces; their rounding and smoothing do not make them abstract; while, conversely, the image that carries an abstract meaning may be as firmly outlined as a steel engraving. The typical image depends upon the inherent strength and weakness of associative tendencies; the abstract meaning is due to determinations which cut across the associative tendencies, perhaps to arrest or short-circuit, perhaps to rearrange them; there can be no necessary connection between typical image and abstract idea.

§ 63. Thought and Language.—It has often been said that thought would be impossible without words; and it is true that we can hardly conceive of human thought save as formed and embodied and expressed in language. Thought and articulate speech grew up, so to say, side by side; each implies the other; they are two sides of the same phase of mental development. The old conundrum ‘Why don’t the animals talk? Because they have nothing to say’ contains so much of sound psychology; if the animals thought, they would undoubtedly use their vocal organs for speech; and since they do not talk, they cannot either be thinking. All this is true: and yet we must acknowledge that thought is not necessarily wedded to speech; it probably appeared, at least in rudimentary guise, before words came into being, and it persists (so to say) after words have ceased to be. There is a gesture-language that can serve as the medium of thought, and that is probably older than speech; and there is a thinking in images and attitudes that dispenses with words.

A gesture is an expressive movement; and all gestures have their origin in the movements that express emotion. But a gesture can serve as the medium of thought only if it is made with the intention to communicate, to impart some meaning; and it is this intention that seems to be the important thing, the specifically human endowment; though we can say nothing more of it now than that it is one of the ingrained tendencies of our nervous system (p. 135). Gestures, at any rate, can give rise to a language of their own; and we may study this language in various dialects; among deaf-mutes who have not been subject to special training; in the Cistercian communities, which are vowed to silence in the ordinary affairs of life; among uncivilised peoples, like the Indian tribes of North America; and finally in the lower strata of civilised societies,—here the Southern Italians are typical. There is a strong family resemblance throughout. We find that gestures express both the feeling-side and the idea-side of emotions; and we find, naturally enough, that development has gone further on the side of idea, where the gesture becomes a means for the expression of thought. The simplest kind of ideational gesture is the demonstrative, which points towards, directly indicates, the object that excites emotion; we point our finger at the thing that has frightened us, or shake our fist at the man who has made us angry. Representative gesture depicts the object: whether by a finger-drawing of its outline in the air, or by the reproduction of one of its characteristic features, or by some purely symbolic movement. Thus, a deaf-mute gesture for ‘smoke’ is a spiral action of the forefinger from below upwards; for ‘child,’ the action of cradling and rocking the right elbow in the left hand; for ‘truth,’ the movement of the forefinger in a straight line from the mouth. This gesture-language has its own syntax, its own laws of growth and change, its own psychological history; but it could not hold its own against articulate speech.

The struggle was, in all probability, brief; because, at the very beginning, speech itself was a gesture; the essential thing about it was not the sound, but the movement. If, then, gesture-language is older than speech, it can hardly be much older; for the sound that accompanied the gesture would soon attract attention, and the superiority of articulate sound over visible movement would soon be recognised. Attempts have been made, of course,—we may say ‘of course’ at this point of our psychological knowledge!—to read a meaning into the sounds themselves. There is a theory which traces the origin of language to the imitation of natural sounds, and so makes it begin with words like hiss and roar; and there is a theory which traces it to ejaculations and merely mechanical utterances, and so makes it begin with oh and ah and a sort of infantile babble. Neither of these theories will hold water. Apart from the psychological arguments, which we cannot here set forth, there is the evidence of fact: words like hiss and roar form a very small part of the vocabulary of any language; exclamations and interjections are emotive and not ideational, and have had but little development; and the babble of the human infant is not primitive, but corresponds with a stage in the maturing of an inherited speech-mechanism. No! the sound was, at first, simply the incidental accompaniment of the gesture, of a movement which included the muscles of the larynx; it derived its meaning from the gesture-context; and presently, under the influence of continued social intercourse, it proved its superiority to gesture and acquired its independence. We may say in the large that the word heard has never had any other than a derivative and symbolic meaning, and that the self-sufficiency of the word-gesture, combined sound and movement, is the origin of language.

What a word should ‘mean,’ therefore, depended in the first instance upon the context and determination of the articulated sound. Just as any idea may serve as an abstract idea, so may any word whatever serve as an abstract verbal idea, as what is technically called a concept, provided only that its context and determination carry the meaning of abstractness. We saw, however, that the context of the abstract idea may drop away, and the mental correlates of its determination lapse, so that finally some conventional image, like the triangle, is taken as abstract, wears the very stamp of abstractness upon it. This is preeminently the case with words. Every generation, we must remember, inherits the speech of preceding generations; language comes to us ready made. We learn from the study of language itself that the abstract words were originally concrete; thus the Latin sapio, to taste, sapor, taste, are connected with sapa, must, sapo, soap, sebum, tallow,—with the names of substances that are readily diluted or liquefied; but the situations that made them abstract dropped out of mind long ago. The child finds language waiting for it, and finds that every word incorporates a meaning; and so it comes about, not only that the mental representation of honesty or pride may be the mere word, ‘honesty’ or ‘pride,’ as it occurs in internal speech, but also that the same internal speech embodies the meaning of abstractness; the verbal image stands psychologically for an idea and logically for a meaning.

§ 64. Mental Attitudes.—If you look back over a course of thought, you will find verbal ideas, and you will perhaps find imaginal complexes of various kinds; but you will also find experiences of another sort, which have come to be known as mental attitudes. They are vague and elusive processes, which carry as if in a nutshell the entire meaning of a situation. Some of them belong to the feeling-side of mind: for feeling enters into the train of directed thought no less than into the freer play of association (p. 161): they are reported as ‘feelings’ of hesitation, vacillation, incapacity, expectancy, surprise, triviality, relevancy, and so on. Others are more nearly related to ideas; they are generally reported by a phrase beginning with ‘I knew that ...,’ ‘I was sure that ...,’ ‘I realised that ...,’ or some like expression. Suppose, for instance, that the observer is required to solve ‘in his head’ some mathematical problem, or to think out the answer to some difficult question that bears upon his special line of study. He may say, in the course of his report: “At that point it occurred to me that I had lost the first partial product,” “It seemed to me that the whole thing was taking too long a time,” “I suddenly realised that I had never thought of that before,” “It flashed upon me that the question was only another form of the old difficulty,” “I could not see the answer, but I knew that I could work it out,” and so forth. All these that-clauses may stand for mental attitudes.

It is clear that, so far as the verbal expressions go, the observer is reporting meanings and not processes. Our task is, then, to discover what processes lie behind the meanings; and here the opinions of psychologists are sharply at variance. One party believes that the mental attitudes are unique and simple, that they cannot be further analysed, and that they must therefore be given rank as mental elements alongside of sensation and feeling. Another party, to which the author belongs, believes that the attitudes are analysable, if only they are taken out of the thought-context and examined by themselves under more favourable conditions, and that their analysis yields nothing else than sensations and feelings. The whole matter is still under discussion, and you will do best to suspend judgement. Meantime we may look at a couple of instances.

Consider, first, the attitude of expectation. It is not difficult to devise experiments which shall set up in the observer an expectant attitude; thus, in a very simple case, the experimenter might hang a weight by a cord to the ceiling, tie a loose piece of string to the cord, and light the end of the string; the observer would then watch the progress of the flame, expecting that it will presently reach the cord, burn that, and so cause the weight to fall to the floor. What are the processes in the observer’s mind as he watches? You will naturally think of an image; the observer will imagine the fall of the weight. Not necessarily; not even usually; the image of expectation must go the same road as the image of recognition (p. 184). Ordinarily, expectation consists simply of kinÆsthetic and organic sensations; sometimes there are verbal ideas; only occasionally is there an image. If the experience is novel, the sensations are likely to be tinged by feeling; there is a trace of anxiety, of apprehension. Analysis reveals nothing more.

We have, then, in expectation a directed experience; the perception of the flaming string acts as a suggestion, turning the observer’s mental processes into a single channel. The kinÆsthetic and organic sensations derive in part from the bodily attitude of attention: tense muscles, inhibited breathing, adjustment of the organ of sight. Yet the observer is not merely attentive; the suggestion, the determination is there; and the sensations derive in part from that. They are contextual processes, and carry the meaning that ‘so-and-so is going to happen.’ They are therefore precisely like the ‘sensations of intended movement’ that characterise the motor reaction (p. 241); we might even call them, following that analogy, ‘sensations of future occurrence.’ All the same, they are, if we regard them as processes, just kinÆsthetic and organic sensations, held together in a certain pattern by the perceptive suggestion; expectation shows nothing unique or ultimate behind or beyond them.

In course of time, if the situation is repeated, the feeling of anxiety fades away, and the experience becomes indifferent. With still further repetition, the ‘sensations of future occurrence’ also drop away; the suggestion from the flaming string then sets the organism, automatically, for the coming event; and the set has no mental correlates whatever.

A like procedure might be followed with vacillation, triviality, and the rest; and the outcome, in the author’s belief, would be the same. It is less easy to attack the intellectual attitudes, those expressed by that-clauses. Suppose, however, that you have to write two letters: the one to an intimate friend, dealing with your home-life and things that have happened in your immediate circle, and the other to a business correspondent, regarding some contract that must be drawn up in precise terms. Do you not sit down to write with a felt difference of bodily attitude, almost as if in the two cases you were a different organism? There are different visceral pressures, differences of tonicity in the muscles of back and legs, differences in the sensed play of facial expression, differences in the movements of arm and hand in the intervals of setting pen to paper, rather obvious differences in respiration, and marked differences of local or general involuntary movement,—all of them deriving from the different suggestions or determinations which prompt the letters. Here, then, are two thats: ‘I was sure that he would be interested in any gossip,’ and ‘I knew very well that I had to write carefully’; and the processes that carry these meanings seem, again, to reduce to a certain pattern of kinÆsthetic and organic sensations, tinged very likely by feeling. When observation reveals such a wealth of sensory processes, it seems unnecessary to assume a new mental element for the intellectual attitudes.

We saw on p. 4 that the concern of science is with facts. But just because facts are the staple of science, it is well that we should be a little jealous about them, that we should scrutinise every alleged fact as severely as our methods allow, and criticise it in the light of every possible theory. That is the present condition of the mental attitude; experiments are being made, and arguments brought forward, for and against its novelty and uniqueness; and the struggle must be carried through to the bitter end; for only in that way can the truth come stably to light. Meantime, those who are in the fight must of necessity take a side; the onlooker, as we have said, is well advised to await the issue.

§ 65. The Pattern of Thought.—There is a broad general resemblance between the pattern of thought and that of constructive imagination; it has indeed been said, though with exaggeration, that thought is an imagining in words, and imagination a thinking in images. The thinker, like the artist, sets out with a plan or design, and aims at a goal; and thought, like imagination, is a more or less steady flow, in a single direction, from the fountain-head of nervous disposition. ‘Happy thoughts’ occur in thinking, as they occur in imagination; there is a like movement between the poles of feeling; and the empathic experiences of the artist are paralleled by the mental attitudes of the thinker. In all these respects, the pattern of thought repeats what has been said on pp. 198 ff. of the pattern of constructive imagination.

Thought, however, has its distinctive features; for it is subject to two of the great directive tendencies that we mentioned on p. 205: the tendency to objectify, to find ‘real things’ in the world about us, and the tendency to dual division. The tendency to objectify underlies perception as well as thought; the earliest ‘real things’ were, we must suppose, external and material things; but with the growth of ideas the tendency bears also upon the things of mind, upon concepts and abstract ideas; these are taken as real in every case of thinking. The tendency to dual division is characteristic of thought; thinking is essentially divisive, even if the goal of thought is constructive. Here, then, is the main difference between thought and constructive imagination: that imagination proceeds to the exhibition of a single something, a statue or a picture or a poem; whereas thought proceeds to the exhibition of two somethings in relation, and ends with what the logicians call a judgement.

The tendency to dual division is so natural to us, and is impressed so deeply in our nervous make-up, that we can hardly hope to go behind it. We can hardly even describe a situation which calls for thought without presupposing the very tendency which is characteristic of thought. For what are the situations? They are situations which ask a question; and we cannot ask a question without putting it in the form of a judgement. Primitive man, wandering from place to place, comes back to a scene that he knew under other circumstances; the tree which was leafy is now bare, the river-bed which was full of water is now dry. If there is no feeling of familiarity, and therefore no recognition, the situation may still ask him: ‘Same?’ and his reply ‘Same scene; different features’ is the reply of thought. He has tried to understand things; his secondary attention has played upon the scene perceived and the scene remembered; he has in the upshot divided the permanent from the changing, the ‘thing’ from the ‘properties’ of the thing; he has reached a conclusion, or formed a judgement.

All thought is of this kind, an answer to a question. Let us take the case of a scientific problem. Suppose that flints, which bear the marks of human workmanship, are found in a Pliocene bed, which has apparently remained undisturbed. The geologist is called upon to decide whether the deposit really has been undisturbed, so that the ‘find’ is reliable evidence of the existence of man in Tertiary times. The situation asks him a number of questions: has the bed been misplaced by faulting? can the materials have been brought to their present position by water? are there any signs that Quaternary man used the place? are the flints associated with bones of Tertiary animals? and so on and so forth. He forms a whole series of judgements; feature after feature of the situation is attended to, and every one in its turn is supplemented by ideas derived from previous knowledge; there is the familiar conflict of secondary attention, repeated over and over. Every judgement affirms or denies some property of the situation, in accordance with the original problem; and the outcome of the series of judgements, of the whole train of thought, is a final judgement,—still, of course, under the determination of the problem,—‘this bed has (or has not) been disturbed’. If the flints themselves are only doubtfully of human workmanship, then the situation is doubly complicated; the questions and the partial judgements are more numerous; but the general pattern of thought is the same.

The tendency to dual division shows itself, then, in the form of the judgement, in the opposition of ‘subject’ to ‘predicate’; it shows itself further in the grammatical distinctions of substantive and adjective, verb and object, verb and adverb. And all thought or reasoning seems to reduce, in the last resort, to a succession of judgements which, under the particular suggestion or determination, exhausts the possibilities of dual division. The duality, however, is not always obvious at first glance. Ideas are involved; and the arousal of a particular idea may mean the excitement of a whole nest of associative tendencies; subject or predicate or both may thus be supplemented in manifold wise; and the train of thought may appear to be variously and irregularly divided. Only a careful observation will show that these supplementary processes derive, not directly from the suggestive situation, but rather from the secondary excitement of associative tendencies. Moreover, the judgements themselves are not always explicit; they may occur in nutshell form, as mental attitudes. The tendency to dual division is thus masked in two ways: by incidental associations, and by attitudes. It seems, nevertheless, to underlie the whole structure of thought.

We are still in the dark as to psychological details. We have evidence that there is no psychological difference between an affirmative and a negative judgement; but we do not even know whether the judgement, affirmative and negative, implies a specific mental pattern of its own, as the idea implies the pattern of core and context, or whether it may express a variety of patterns. On the whole, the latter alternative seems the more probable; if there is any stable characteristic of the judgement, it is not a definite pattern or arrangement of mental processes, but rather a definite mental attitude, the ‘feeling of validity’; and this attitude seems to be allied to the feeling of familiarity in recognition, and so to be remotely akin to the emotion of relief. As far as our evidence goes, it appears to accompany every true judgement, that is to say, every judgement which is formed in the state of secondary attention. A ‘feeling of relation’ need not accompany the final judgement, but is likely to crop up here and there in the course of a train of thought, assuring us that certain things go together, belong to the same ‘circle’ of ideas, and that certain other things are contradictory, and cannot go together. These relational feelings or attitudes are contextual affairs, deriving probably from the kinÆsthesis of bodily attitude; they are, however, very difficult to analyse, and their precise psychological nature is still in dispute.

In conclusion, let us revert for a moment to the comparison of thought with constructive imagination. We have said that the two are broadly similar; and we may now add that judgements occur in imagination, and fetches of imagination in a train of thought. The differences are, nevertheless, great enough to justify the popular distinction of the two mental modes; for thought advances by repeated dissections of a situation which is taken as real, while imagination realises in the work of art a situation which at first was vague or fragmentary.

§ 66. Abstraction and Generalisation.—We have spoken of the abstract or general idea, as if the two adjectives were interchangeable; and abstraction and generalisation are, in fact, only two phases of the same procedure. When we abstract, we pick out the features of a situation that are relevant to our present determination, and neglect the other features. When we generalise, we bring to light resemblances that have been merged with differences; but this statement implies that we neglect the differences, as irrelevant, and pick out the likenesses, as relevant; generalisation is thus only a special case of abstraction. We have seen that every suggestion is double-faced, positive as well as negative; and we may perhaps say that in thinking of abstraction we emphasise the negative face, the discarding of the irrelevant, while in thinking of generalisation we emphasise the positive face, the bringing together of the similars which are relevant.

Experiments upon abstraction may be made in the manner outlined on p. 250: a complex stimulus (say, a visual stimulus that shows differences of colour, of number, of arrangement) is exhibited for a brief time; the observer is asked to attend to some one aspect of it (say, colour); and then, his report given, is asked to state what he can of the other aspects (number and form). Two general results may be mentioned. It is found, as might perhaps have been expected, that things which make the least appeal to attention are also the things most easily overlooked. Colour and form, for instance, are more attractive than number; and when the observer is told to attend to colour or form, number may go entirely unnoticed; whereas, when he is told to attend to number,—a relatively difficult task,—he is still able to say something of colour and form. The result seems only natural; but you may not see at once that it throws scientific light on a matter of some practical importance. We all know from sad experience that when thought, our own or another’s, flows smoothly and easily, it is likely to be superficial; the very smoothness of the flow means that difficulties have been overlooked. The obverse of this fact is, now, that if we struggle with the knotty points of a subject, we get a grip upon the whole; the interesting and attractive things take care of themselves; their native appeal to the attention keeps them in mind. So the experiments upon abstraction point a moral, at the same time that they illustrate the nervous mechanism of thought itself. They show, secondly, that the negative effect of abstraction varies in degree; the aspects of stimulus from which we abstract may be wholly suppressed, so that no report at all can be made of them, or may be apprehended indefinitely, so that the report is general; thus, form may be correctly named, while the colours are reported merely as ‘different,’ or as ‘dark.’ Another significant result! for it means that a concept is more easily touched off than a special name; we may fail to identify colours as red or blue when we can still say that they are dark or different. The reason is that the concept, the general name, is applied far oftener than the special name; its associative tendencies are therefore both deeper seated and more numerous. We have a parallel case in the image of p. 266, which slowly loses its distinctive features and approaches a type; and we have others in the gradual decay of memory with old age: a grandfather may forget the names of his grandchildren, but he does not forget that they are ‘boys’ and ‘girls.’