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 excitement and ennui, are due to such causes, more immediate 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, i is not what it is because those events are past, but because they have left behind them processes which are present. To those processes, however caused, the mind would 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 occurredso 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 overlap; and the new-created man would unquestionably have the feeling, at the very primal instant of his life, of havi 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 tingers, he names it without difficulty. This patient has thus lost the capacity for grouping successive . . . impressions . . . into a whole and perceiving them as a whole." (Grashey, in Archiv für Psychiatrie, Bd. xvi. pp. 672-673.) It is hard to believe that in such a patient the time intuited was not clipped off 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 something 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 I 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 has to be specially revoked in memory. This mode of revocation usually characterizes longpast things-whence the illusion.

* Again I omit the future. merely for simplicity's sake.

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, shorter ones by dividing, portions of this vaguely bounded unit, and are habitually thought by us symbolically. 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.

CHAPTER XVI.

MEMORY.

In the last chapter what concerned us was the direct intuition of time. We found it limited to intervals of considerably 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 conceived 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 canvas in our memory, and yet often imagine that we have direct vision of its depths.

The stream of thought flows on; but most of its segments 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?

PRIMARY MEMORY.

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 substantive 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 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 segments 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 permanent a factor is it of our world. An indelibly-imprinted pain may color a life; but, as Professor Richet 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 determine the transition of our thinking in a vital way, and decide our action irrevocably.† But the idea of it could not

* L'Homme et l'Intelligence, p. 32.

+ 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 experienced 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.

afterwards determine transition and action, its content could not be conceived as one of the mind's permanent meanings: that is all I mean by saying that its intellectual value lies in after-memory.

As a rule sensations outlast for some little time the objective stimulus which occasioned them. This phenomenon is the ground of those after-images' which are familiar in the physiology of the sense-organs. If we open our eyes instantaneously upon a scene, and then shroud them in complete darkness, it will be as if we saw the scene in ghostly light through the dark screen. We can read off details in it which were unnoticed whilst the eyes were open.*

In every sphere of sense, an intermittent stimulus, often enough repeated, produces a continuous sensation. This is because the after-image of the impression just gone by blends with the new impression coming in. The effects of stimuli may thus be superposed upon each other many stages deep, the total result in consciousness being an increase in the feeling's intensity, and in all probability, as we saw in the last chapter, an elementary sense of the lapse of time (see p. 635).

coexisting with the multitude of other sensations which are juxtaposed in consciousness alongside of this one persistent emotion which is felt always in the present tense. A long time is needed ere we can attain to forgetting it, ere we can make it enter into the past. Hæret lateri letalis arundo.” (Ibid 583)

This is the primary positive after image. According to Helmholtz, one third of a second is the most favorable length of exposure to the light for producing it. Longer exposure, complicated by subsequent admission of light to the eye, results in the ordinary negative and complementary after-images, with their changes, which may (if the original impression was brilliant and the fixation long) last for many minutes. Fechner gives the name of memory-after images (Psychophysik, II 492) to the instantaneous positive effects, and distinguishes them from ordinary after images by the following characters: 1) Their originals must have been attended to, only such parts of a compound original as have been attended to appearing. This is not the case in common visuai after images. 2) The strain of attention towards them is inward, as in ordinary remembering, not outward, as in observing a common after-image. 3) A short fixation cf the original is better for the memory-after-image, a long one for the ordinary after-image. 4) The colors of the memory-after-image are never complementary of those of the original.