The Principles of Psychology, Vols. 1-2

Mr. Ward gives, in his Encyclopaedia Britanniea article (Psychology, p. 65, col. 1), a still more refined attempt to specify the 'temporal sign.' The problem being, among a number of other things thought as successive, but simultaneously thought, to determine which is first and which last, he says: "After each distinct representation, abed, there may inter vene the representation of that movement of attention of which we are aware in passing from one object to another. In our present reminiscence we have, it must be allowed, little direct proof of this intervention ; though there is, I think, indirect evidence of it in the tendency of the flow of ideas to follow the order in which the presentations were at first attended to. With the movement itself when the direction of attention changes, we are familiar enough, though the residua of such movements are not ordinarily conspicuous. These residua, then, are our temporal signs. . . . But tem poral signs alone will not furnish all the pictorial exactness of the time-per spective. These give us only a fixed series; but the law of oblivisceuce, by insuring a progressive variation in intensity as we pass from one member of the series to the other, yields the effect which we call time-distance. By themselves such variations in intensity would leave us liable to confound more vivid representations in the distance with fainter ones nearer the present, but from this mistake the temporal signs save us ; where the memory-continuum is imperfect such mistakes continually occur. On the other hand, where these variations are slight and imperceptible, though the memory-continuum preserves the order of events intact, we have still no such distinct appreciation of comparative distance in time as we have nearer to the present, where these perceptive effects are considerable. . . .

Locke speaks of our ideas succeeding each other ' at certain distances not much unlike the images in the inside of a lantern turned round by the heat of a candle, 'and 'guesses' that 'this appearance of theirs in train varies not very much in awaking man.' Now what is this ' distance ' that separates a from b, bfrom c, and so on ; and what means have we of knowing that it is tolerably constant in waking life? It is, probably, that, the residuum of which I have called a temporal sign; or, in other words, it is the movement of attention from a to b." Nevertheless, Mr. Ward does not call our feeling of this movement of attention the original of our feeling of time, or its brain -process the brun-process which directly causes us to perceive time. He says, a moment later, that " though the fixation of attention does of course really occupy time, it is probably not in the first instance perceived as time— i.e. as continuous ' protensily,' to use a term of Hamilton's— but as intensity. Thus, if this supposition be true, there is an element in our concrete time perceptions which has no place in our abstract conception of Tim*. In Time physically conceived there is no trace of intensity ; in time

The phenomena of ' summation of stimuli ' in the nervous system prove that each stimulus leaves some latent activity psychically experienced, duration is primarily an intensive magnitude, and so far literally a perception." Its 'original' is, then, if I understand Mr Ward, something like a feeling which accompanies, as pleasure and pain may accompany, the movements of attention. Its brain-process must, it would seem, be assimilated in general type to the brain -processes of pleasure and pain. Such would seem more or less consciously to be Mr. Ward's own view, for he says : " Everybody knows what it is to be distracted by a rapid succession of varied impressions, and equally what it is to be wearied by the slow and monotonous recurrence of the same impressions. Now these ' feelings ' of distraction and tedium owe their characteristic qualities to movements of attention. In the first, attention is kept incessantly on the move ; before it is accommodated to a, it is disturbed by the sudden ness, intensity, and novelty of b ; in the second, it is kept all but stationary by the repeated presentation of the same impression. Such excess and defect of surprises make one realize a fact which in ordinary life is so obscure as to escape notice. But recent experiments have set this fact in a more striking light, and made clear what Locke had dimly before his mind in talking of a certain distance between the presentations of a waking man. In estimating very short periods of time of a second or less, indicated, say, by the beats of a metronome, it is found that there is a certain period for which the mean of a number of estimates is correct, while shorter periods are on the whole over-, and longer periods under-estimated.

I take this to be evidence of the time occupied in accommodating or fixing attention.' Alluding to the fact that a series of experiences, a b c d e, may seen* short in retrospect, which seemed everlasting in passing, he says: " What tells in retrospect is the series abode, etc.; what tells in the present is the intervening t\ ty t<, , etc., or rather the original accommodation of which these temporal signs are the residuum." And he concludes thus : "We seem to have proof that our perception of duration rests ultimately upon quasi-motor objects of varying intensity, the duration of which we do not directly experience as duration at all."

Wundt also thinks that the interval of about three-fourths of a second, which is estimated with the minimum of error, points to a connection between the time-feeling and the succession of distinctly ' apperceived ' objects before the mind. The 'association-time' is also equal to about thr£e fourths of a second. This association-time he regards as a sort of ;uterual standard of duration to which we in voluntarily assimilate all inter vals which we trj to reproduce, bringing shorter ones up to it and longer ones down. [In the Stevens result we should have to say contrast instead of assimilate, for the longer intervals there seem longer, and the shorter ones shorter still.] "Singularly enough," he adds (Physiol. Psych., IT. 286), " this time is about that in which in rapid walking, according to the Webers, our legs perform their swing. It seems thus not unlikely that both psychical constants, that of the average speed of reproduction and that of the surest estimation of time, have formed themselves under the influ ence of those most habitual movements of the body which we also use when w? try to subdivide rhythmically longer tracts of time."

jehind it which only gradually passes away. (See above, pp. 82-85.) Psychological proof of the same fact is afforded by those ' after-images ' which we perceive when a sensorial stimulus is gone. We may read off peculiarities in an after-image, left by an object on the eye, which we failed to note in the original. We may ' hark back ' and take in the meaning of a sound several seconds after it has ceased. Delay for a minute, however, and the echo itself of the clock or the question is mute ; present sensations have banished it beyond recall. With the feeling of the present thing there must at all times mingle the fading echo of all those other things which the previous few seconds have supplied. Or, to state it in neural terms, there is at every moment a cumulation of brain-processes overlapping each other, of ivhich the fainter ones are the dying phases of processes ivhich bict shortly previous were active in a maximal degree. The AMOUNT OF THE OVERLAPPING determines the feeling of the DURATION OCCUPIED. WHAT EVENTS shall appear to occupy the duration depends on just WHAT PROCESSES the overlapping pro cesses are. We know so little of the intimate nature of the brain's activity that even where a sensation monotonously endures, we cannot say that the earlier moments of it do

Finally, Prof. Mach makes a suggestion move specific still. After say ing very rightly that we have a real sensation of time — how otherwise should we identify two entirely different airs as being played in the same 'time'? how distinguish in memory the first stroke of the clock from the second, unless to each there clove its special time-sensation, which revived with it? — he says "it is probable that this feeling is connected with that organic consumption which is necessarily linked with the production of conscious ness, and that the time which we feel is probably due to the [mechanical?] work of [the process of ?] attention. When attention is strained, time seems long; during easy occupation, short, etc. . . . The fatigue of the organ of consciousness, as long as we wake, continually increases, and the work of attention augments as continually. Those impressions which are conjoined with a greater amount of work of attention appear to us as the later." The apparent relative displacement of certain simultaneous events and certain anachronisms of dreams are held by Mach to be easily explicable as effects of a splitting of the attention between two objects, one of which consumes most of it (Beitnlge zur Analyse der Empfindungen, p. 103 foil.). Mach's theory seems worthy of being better worked out. It is hard to say now whether he, Ward, and Wundt mean at bottom the same thing or not. The theory advanced in my own text, it will be remarked, does not pretend to bean explanation, but only an elementary statement of the 'law' whic> makes us aware of time. The Herbartian mythology purports to explain

not leave fading processes behind which coexist with those of the present moment. Duration and events together form our intuition of the specious present with its content.* Why such an intuition should result from such a combination of brain-processes I do not pretend to say. All I aim at is to state the most elemental form of the psycho-physical con junction. I have assumed that the brain-processes are sensational ones. Processes of active attention (see Mr. Ward's account in the long foot-note) will leave similar fading brain-pro cesses behind. If the mental processes are conceptual, a complication is introduced of which I will in a moment speak. Meanwhile, still speaking of sensational processes, a remark of Wundt's will throw additional light on the account I give. As is known, Wundt and others have proved that every act of perception of a sensorial stimulus takes an appreciable time. When two different stimuli — e.g. a sight and a sound — are given at once or nearly at once, we have difficulty in attending to both, and may wrongly judge their interval, or even invert their order. Now, as the result of his experiments on such stimuli. Wundt lays down this law : t that of the three possible de terminations we may make of their order —

"namely, simultaneity, continuous transition, and discontinuous tran sition — only the first and last are realized, never the second. Invari ably, when we fail to perceive the impressions as simultaneous, we notice a shorter or longer empty time between them, wlricli seems to correspond to the sinking of one of the ideas and to the rise of the other. . . . For our attention may share itself equally between the two impressions, which will then compose one total percept [and be simultaneously felt]; or it may be so adapted to one event as to cause

* It would be rash to say definitely just how many seconds long this specious present must needs be, for processes fade ' asymptotically,' and the distinctly intuited present merges into a penumbra of mere dim recency before it turns into the past which is simply reproduced and conceived. Many a thing which we do not distinctly date by intercalating it in a place between two other things will, nevertheless, come to us with this feeling of belonging to a near past. This sense of recency is a feeling sui generis, and may affect things that happened hours ago. It would seem to show that their brain-processes are still in a state modified by the foregoing excite ment, still in a ' fading ' phase, in spite of the long interval.

it to be perceived immediately, and then the second event can be per ceived only after a certain time of latency, during which the attention reaches its effective maximum for it and diminishes for the first event. In this case the events are perceived as two, and in successive order — that is, as separated by a time-interval in which attention is not sufficient ly accommodated to either to bring a distinct perception about. . . . While we are hurrying from one to the other, everything between them vanishes in the twilight of general consciousness." *

One might call this the law of discontinuous succession in lime, of percepts to tvhich we cannot easily attend at once. Each percept then requires a separate brain-process ; and when one brain-process is at its maximum, the other would ap pear perforce to be in either a waning or a waxing phase. If our theory of the time-feeling be true, empty time must then subjectively appear to separate the two percepts, no matter how close together they may objectively be ; for, according to that theory, the feeling of a time-duration is the immediate effect of such an overlapping of brain-pro-

*1 leave my text as it was printed before Miinsterberg's essay appeared (see above page 620, note). He denies that we measure any but minimal durations by the amount of fading in the ideatioual processes, and talks almost exclusively of our feelings of muscular tension in his account, whereas I have made no mention of such things in mine. I cannot, how ever, see that there is any conflict between what he and I suggest. I am mainly concerned with the consciousness of duration regarded as a specific sort of object, he is concerned with this object's measurement exclusively. Feelings of tension might be the means of the measurement, whilst overlap ping processes of any and every kind gave the object to be measured. The accommodative and respiratory movements from which the feelings of tension come form regularly recurring sensations divided by their ' phases ' into intervals as definite as those by which a yardstick is divided by the marks upon its length.

Let a1, a2, a3, a4, be homologous phases in four successive movements of this kind. If four outer stimuli 1, 2, 3, 4, coincide each with one of these successive phases, then their 'distances apart ' are felt as equal, other wise not. But there is no reason whatever to suppose that the mere over lapping of the brain-process of 2 by the fading process of 1, or that of 8 by that of 2, etc., does not give the cJiaracteristic quality of content which we call ' distance apart ' in this experience, and which by aid of the muscular feelings gets judged to be equal. Doubtless the muscular feelings can give us the object ' time ' as well as its measure, because their earlier phases leave fading sensations which constantly overlap the vivid sensation of the present phase. But it would be contrary to analogy to suppose that they should be the only experiences which give this object. 1 do not understand Herr Munsterberg to claim this for them. He takes our seme of time for granted, and only discusses its measurement.

cesses of different phase — wherever and from whatever cause it may occur. To pass, now, to conceptual processes : Suppose I think of the Creation, then of the Christian era, then of the battle of Waterloo, all within a few seconds. These matters have their dates far outside the specious present. The pro cesses by which I think them, however, all overlap. What events, then, does the specious present seem to contain? Simply my successive acts of thinking these long-past things, not the long-past things themselves. As the in stantly-present thought may be of a long-past thing, so the just-past thought may be of another long-past thing. When a long-past event is reproduced in memory and conceived with its date, the reproduction and conceiving traverse the specious present. The immediate content of the latter is thus all my direct experiences, whether subjective or ob jective. Some of these meanwhile may be representative of other experiences indefinitely remote.

The number of these direct experiences which the specious present and immediately-intuited past may em brace measures the extent of our ' primary,' as Exner calls it, or, as Richet calls it, of our ' elementary ' memory.* The sensation resultant from the overlapping is that of the duration which the experiences seem to fill. As is the num ber of any larger set of events to that of these experiences, so we suppose is the length of that duration to this duration. But of the longer duration we have no direct * realizing sense.' The variations in our appreciation of the same amount of real time may possibly be explained by altera tions in the rate of fading in the images, producing changes in the complication of superposed processes, to which changes changed states of consciousness may correspond. But however long ivemay conceive a space of time to be, the objective amount of it which is directly perceived at any one moment by us can never exceed the scope of our * primary memory ' at the moment in question.!

f I have spoken of fading brainprocesses alone, but only for simplicity's sake. Dawning processes probably play as important a part in giving the feeling of duration to the specious present. We have every reason to think that creatures may possi bly differ enormously in the amounts of duration which they intuitively feel, and in the fineness of the events that may fill it. Yon Bser has indulged* in some interesting compu tations of the effect of such differences in changing the aspect of Nature. Suppose we were able, within the length of a second, to note 10,000 events distinctly, instead of barely 10, as now ; if our life were then destined to hold the same number of impressions, it might be 1000 times as short. We should live less than a month, and personally know nothing of the change of seasons. If born in winter, we should believe in summer as we now believe in the heats of the Carbonifer ous era. The motions of organic beings would be so slow to our senses as to be inferred, not seen. The sun would stand still in the sky, the moon be almost free from change, and so on. But now reverse the hypothesis and suppose a being to get only one 1000th part of the sensations that we get in a given time, and consequently to live 1000 times as long. Winters and summers will be to him like quarters of an hour. Mushrooms and the swifter-growing plants will shoot into being so rapidly as to appear instantaneous creations ; annual shrubs will rise and fall from the earth like restlessly boilingwater springs ; the motions of animals will be as invisible as are to us the movements of bullets and cannon-balls ; the sun will scour through the sky like a meteor, leaving a fiery trail behind him, etc. That such imaginary cases (barring the superhuman longevity) may be realized somewheie in the animal kingdom, it would be rash to deny.

"A gnat's wings,' says Mr Spencor,t " make ten or fifteen thousand strokes a second. Each stroke implies a separate nervous action. Each sucn nervous action or change in a nervous centre is probably as ap preciable by the gnat as is a quick movement of his arm by a man. And if this, or anything like this, is the fact, then the time occupied by a given external change, measured by many movements in the one case, must seem much longer than in the other case, when measured by one movement."

Iii hashish-intoxication there is a curious increase in the apparent time-perspective. We utter a sentence, and ere fclie end is reached the beginning seems already to date from indefinitely long ago. We enter a short street, and it is aa if we should never get to the end of it. This alteration might conceivably result from an approach to the condition of Von Brer's and Spencer's short-lived beings. If our dis crimination of successions became finer-grained, so that we noted ten stages in a process where previously we only noted one ; and if at the same time the processes faded ten times as fast as before ; we might have a specious present of the same subjective length as now, giving us the same time-feeling and containing as many distinguishable suc cessive events, but out from the earlier end of it would have dropped nine tenths of the real events it now contains. They would have fallen into the general reservoir of merely dated memories, reproducible at will. The beginning of our sentences would have to be expressly recalled ; each word would appear to pass through consciousness at a tenth of its usual speed. The condition would, in short, be ex actly analogous to the enlargement of space by a micro scope ; fewer real things at once in the immediate field of view, but each of them taking up more than its normal room, and making the excluded ones seem unnaturally far away.

Under other conditions, processes seem to fade rapidly without the compensating increase in the subdivisibility of successions. Here the apparent length of the specious present contracts. Consciousness dwindles to a point, and loses all intuitive sense of the whence and whither of its path. Express acts of memory replace rapid bird's-eye views. In my own case, something like this occurs in ex treme fatigue. Long illnesses produce it. Occasionally, it appears to accompany aphasia.* It would be vain to seek

*"The patient cannot retain the image of an object more than a moment. His memory is as short for sounds, letters, figures, and printed words. If we cover a written or printed word with a sheet of paper in which a little window has been cut, so that only the first letter is visible through the window, he pronounces this letter. If, then, the sheet is moved so as to cover the first letter and make the second one visible, he pro nounces the second, but forgets the first, and cannot pronounce the first and second together." And so forth to the end. " If he closes his eyes and draws his finger explori'igly over a well known object like a knife or key

to imagine the exact brain-change in any of these cases. But we must admit the possibility that to some extent the variations of time-estimate between youth and age, and ex citement and ennui, are due to such causes, more immedi ate than to the one we assigned some time ago. But whether our feeling of the time which immediately -past * events have filled be of something long or of something short, ii is not ivhat it is because tliose events are past, but because they have left behind them processes which are present. To those pro cesses, however caused, the mind ivould still respond by feeling a specious present, with one part of it just vanishing or vanished into the past. As the Creator is supposed to have made Adam with a navel — sign of a birth which never occurred — • so He might instantaneously make a man with a brain in which were processes just like the ' fading ' ones of an ordi nary brain. The first real stimulus after creation would set up a process additional to these. The processes would over lap ; and the new-created man would unquestionably have the feeling, at the very primal instant of his life, of liaviiito been in existence already some little space of time.

he cannot combine the separate impressions and recognize the object. But if it is put into his hand so that he can simultaneously touch it with several fingers, he names it without difficulty. This patient has thus lost the ca pacity for grouping successive . . . impressions . . . into a whole and per ceiving them as a whole." (Grashey, in Archiv fiir Psychiatric, Bd. xvi. pp. 672-673.) It is hard to believe that in such a patient the time intuited was not clipped oil' like the impressions it held, though perhaps not so much of it.

I have myself often noted a curious exaggeration of time-perspective at the moment of a falling asleep. A person will be moving or doing some thing in the room, and a certain stage of his act (whatever it may be) will be my last waking perception. Then a subsequent stage will wake me to a new perception. The two stages of the act will not be more than a few seconds apart ; and yet it always seems to me as if, between the earlier and the later one, a long interval has passed away. I conjecturally account for the phenomenon thus, calling the two stages of the act a and b respectively : Were 1 awake, a would leave a fading process in my sensorium which would overlap the process of b when the latter came, and both would then appear in the same specious present, a belonging to its earlier end. But the sudden advent of the brain-change called sleep extinguishes a's fading process abruptly. When b then comes and wakes me, a comes back, it is true, but not as belonging to the specious present. It lias to be specialty revoked in memory. This mode of revocation usually characterizes longpast things — whence the illusion.

Let me sum up, now, by saying that we are constantly con scious of a certain duration — the specious present — varying in length from a few seconds to probably not more than a minute, and that this duration (with its content perceived as having one part earlier and the other part later) is the original intuition of time. Longer times are conceived by adding, chorter ones by dividing, portions of this vaguely bounded unit, and are habitually thought by us symboli cally. Kant's notion of an intuition of objective time as an infinite necessary continuum has nothing to support it. The cause of the intuition which we really have cannot be the duration of our brain-processes or our mental changes. That duration is rather the object of the intuition which, being realized at every moment of such duration, must be due to a permanently present cause. This cause — probably the simultaneous presence of brain-processes of different phase — fluctuates ; and hence a certain range of variation in the amount of the intuition, and in its subdivisibility, accrues.

IN the last chapter what concerned us was the direcV intuition of time. We found it limited to intervals of con siderably less than a minute. Beyond its borders extends the immense region of conceived time, past and future, into one direction or another of which we mentally project all the events which we think of as real, and form a systematic order of them by giving to each a date. The relation of con ceived to intuited time is just like that of the fictitious space pictured on the flat back-scene of a theatre to the actual space of the stage. The objects painted on the former (trees, columns, houses in a receding street, etc.) carry back the series of similar objects solidly placed upon the latter, and we think we see things in a continuous perspective, when we really see thus only a few of them and imagine that we see the rest. The chapter which lies before us deals with the way in which we paint the remote past, as it were, upon a canvas in onr memory, and yet often imagine that we have direct vision of its depths.

The stream of thought flows on; but most of its seg ments fall into the bottomless abyss of oblivion. Of some, no memory survives the instant of their passage. Of others, it is confined to a few moments, hours, or days. Others, again, leave vestiges which are indestructible, and by means of which they may be recalled as long as life endures. Can we explain these differences? The first point to be noticed is that for a state of mind to survive in memory it must have endured for a certain length of time. In other words, it must be what I call a substan tive state. Prepositional and conjunctival states of mind are not remembered as independent facts — we cannot recall

just how we felt when we said 'how* or 'notwithstanding.' Our consciousness of these transitive states is shut up to 1 1 their own moment — hence one difficulty in introspective psychologizing. Any state of mind which is shut up to its own moment and fails to become an object for succeeding states of mind, is as if it belonged to another stream of thought. Or rather, it belongs only physically, not intellectually, to its own stream, forming a bridge from one segment of it to another, but not being appropriated inwardly by former seg ments or appearing as part of the empirical self, in the manner explained in Chapter X. All the intellectual value for us of a state of mind depends on our after-memory of it. Only then is it combined in a system and knowingly made to contribute to a result. Only then does it count for us. So that the EFFECTIVE consciousness we have of our states is the after-consciousness ; and the more of this there is, the more influence does the original state have, and the more perma nent a factor is it of our world. An indelibly-imprinted pain may color a life ; but, as Professor Bichet says :

" To suffer for only a hundredth of a second is not to suffer at all ; and for my part I would readily agree to undergo a pain, however acute and intense it might be, provided it should last only a hundredth of a second, and leave after it neither reverberation nor recall." * Not that a momentary state of consciousness need be practically resultless. Far from it : such a state, though absolutely unremembered, might at its own moment deter mine the transition of our thinking in a vital way, and de cide our action irrevocably.! But the idea of it could not

f Professor Richet has therefore no right to say, as he does in another place (Revue Philosophique, xxi. 570): " Without memory no conscious sensation, without memory no consciousness." All he is entitled to say is. "Without memory no consciousness known outside of itself." Of the sort of consciousness that is an object for later states, and becomes as it were permanent, he gives a good example: "Who of us, alas ! has not ex perienced a bitter and profound grief, the immense laceration cause by the death of some cherished fellow-being? Well, in these great griefs the ( present endures neither for a minute, for an hour, nor for a day, but for \ weeks and months. The memory of the cruel moment will not efface itself from consciousness. It disappears not, but remains living, present.