64 PSYCHOLOGY . of BC ... on the recurrence of A, i.e., provided the memory-train continues so far intact. Such expectation, at first perhaps slight a mere tendency easily overborne becomes strengthened by every repetition of the series in the old order, till eventually, if often fulfilled and never falsified, it becomes certain and, as we commonly say, irresistible. To have a clear case of expectation, then, it is not necessary that we should distinctly remember any previous experience like it, but only that we should have actually present some earlier member of a series which has been firmly associated by such previous experiences, the remaining members, or at least the next, if they continue serial, being revived through that which is once again realized. This expectation may be instantly checked by reflexion, just as it may of course be disappointed in fact ; but these are matters which do not concern the inquiry as to the nature of expectation while expectation lasts. Present, We shall continue this inquiry to most advantage by past. now widening it into an examination of the distinction of present, past, and future. To a being whose presenta- tions never passed through the transitions which ours undergo -first divested of the strength and vividness of impressions, again reinvested with them and brought back from the faint world of ideas the sharp contrasts of "now" and " then," and all the manifold emotions they occasion, would be quite unknown. Even we, so far as we confine our activity and attention to ideas, are almost without them. Time -order, succession, antecedence and consequence, of course, there might be still, but in that sense of events as " past and gone for ever," which is one of the melancholy factors in our life ; and in the obligation to wait and work in hope or dread of what is " still to come " there is much more than time -order. It is to presentations in their primary stage, to impressions, that we owe what real differ- ence we find between now and then, whether prospective or retrospective, as it is to them also that we directly owe our sense of the real, of what is and exists as opposed to the non-existent that is not. But the present alone and life in a succession of presents, or, in other words, continuous occupation with impressions, give us no knowledge of the present as present. This we first obtain when our present consciousness consists partly of memories or partly of ex- pectations as well. An event expected differs from a like event remembered chiefly in two ways in its relation to present impressions and images and in the active attitude to which it leads. The diverse feelings that accompany our intuitions of time and contribute so largely to their colour- ing are mainly consequences of these differences. Let us take a series of simple and familiar events ABCDE, re- presenting ideas by small letters and perceptions by capitals whenever it is necessary to distinguish them. Such series may be present in consciousness in such wise that abed are imaged while jE"is perceived anew, i.e., the whole symbolized as proposed would be abcdE; such would be, e.g., the state of a dog which had just finished his daily meal. Again, there may be a fresh impression of A which revives bcde; we should have then (1) A bcde the state of our dog when he next day gets sight of the dish in which his food is brought to him. A little later we may have (2) abC de, Here a b are either after-sensations or primary memory- images, or have at any rate the increased intensity due to recent impression ; but this increased intensity will be rapidly on the wane even while C lasts, and a b will pale still further when C gives place to D, and we have (3) abcDe. But, returning to (2), we should find de to be in- creasing in intensity and definiteness, as compared with their state in (1), now that C, instead of A, is the present impression. For, when A occupied this position, not only was e raised less prominently above the threshold of con- sciousness by reason of its greater distance from A in the memory-continuum, but, owing to the reduplications of this continuum, more lines of possible revival were opened up, to be successively negatived as B succeeded to A and C to B ; even dogs know that "there is many a slip 'twixt the cup and the lip." But, where A B C D E is a series of percepts such as we have here supposed and a series of simpler states would hardly afford much ground for the distinctions of past, present, and future there would be a varying amount of active adjustment of sense-organs and other movements supplementary to full sensation. In (2), the point at which we have ab C de, for instance, such adjustments and movements as were appropriate to b would cease as B lapsed and be replaced by those appropriate to C. Again, as C succeeded to B, and d in consequence increased in intensity and definiteness, the movements adapted to the reception of D would become nascent, and so on. Thus, psychologically regarded, the distinction of past and future and what we might call the oneness of direction of time depend, as just described, (1) upon the continuous sinking of the primary memory -images on the one side, and the continuous rising of the ordinary images on the other side, of that member of a series of percepts then repeating which is actual at the moment ; and (2) on the prevenient adjustments of attention, to which such words as "expect," "await," "anticipate," all testify by their etymology. These conditions in turn will be found to depend upon all that is implied in the formation of the memory-train and upon that recurrence of like series of impressions which we attribute to the " uniformity of nature." If we never had the same series of impressions twice, knowledge of time would be impossible, as indeed would knowledge of any scrt. This is perhaps the fittest point at which to inquire into Sue the character and origin of our knowledge of succession sio1 and duration, so far, that is, as such an inquiry belongs to psychology. We have not to ask how time itself comes to be ; but, assuming it to be, we ask how the individual comes to know it. Time is often figuratively represented as a line, and we may perhaps utilize this figure to make clear the relation of our intuition of time to what we call time itself. Time, then, we say, stretches backwards and forwards from the present moment. But the present, though a point of time, is still such that we can and do in that moment attend to a plurality of presentations to which we might otherwise have attended severally in suc- cessive moments. Granting this implication of simul- taneity and succession, we may, if we represent succession as a line, represent simultaneity as a second line at right angles to the first ; empty time or time-length without time-breadth, we may say is a mere abstraction. Now it is with the former line that we have to do in treating of time as it is, and with the latter in treating of our intuition of time, where, just as in a perspective repre- sentation of distance, we are confined to lines in a plane at right angles to the actual line of depth. In a succession of events, say of sense-impressions, ABCDE. . . the presence of B means the absence of A and of (7, but the presentation of this succession involves the simultaneous presence, in some mode or other, of two or more of the presentations A BC D. In presentation, as we have seen, all that corresponds to the differences of past, present, and future is in consciousness simultaneously. This truism or paradox that all we know of succession is but an interpretation of what is really simultaneous or co- existent, we may then concisely express by saying that we are aware of time only through time -perspective, and experience shows that it is a long step from a succession of presentations to such presentation of succession. The first condition is that we should have represented together presentations that were in the first instance attended to
