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: that of the three possible determinations we may make of their order --
"namely, simultaneity, continuous transition, and discontinuous transition -- only the first and last are realized, never the second.Invariably, when we fail to perceive the impressions as simultaneous, we notice a shorter or longer empty time between them, which 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 ; or it may be so adapted to one event as to cause it to be perceived immediately, and then the second event can be perceived 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 sufficiently 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 time, of percepts to which 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 appear 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-
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 processes 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 instantly-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 objective.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 embrace 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 number 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 alterations 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 we may 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.
We have every reason to think that creatures may possibly differ enormously in the amounts of duration which they intuitively feel, and in the fineness of the events that may fill it.Von Bær has indulged
in some interesting computations 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 Carboniferous 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 boiling-water 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 somewhere in the animal kingdom, it would be rash to deny.
