(C) Theory of Presentations (cont.)
There is yet one more topic of a general kind calling for attention before we turn to the consideration of particular presentationsthe hypothesis of unconscious mental modifications, as it has been unfortunately termed,the hypothesis of subconsciousness, as we may style it to avoid this contradiction in terms. It is a fact easily verified, that we do not distinguish or attend separately to presentations of less that a certain assignable intensity. On attaining this intensity presentations are said to pass over the threshold o consciousness, to use Herbarts now classic phrase. What are we to say of them before they have attained it? After they have attained it, any further increase in their intensity is certainly gradual ; are we then to suppose that before this their intensity changed instantly from zero to a finite quantity, and not rather that there was also a subliminal stage where too it only changed continuously? The latter alternative constitutes the hypothesis of subconsciousness. According to this hypothesis, a presentation does not cease to be so long as it has any intensity, no matter how little. We can directly observe that an increase in the intensity of many complex presentations brings to light details and differences before imperceptible ; since these details are themselves presentations, they have been brought by this increase from the subconscious stage into the field of consciousness. Similarly, presentations not separately distinguishable, because of too close a proximity in time, become distinguishable when the interval between them is such as to allow of a separate concentration of attention upon each. Again, we find that presentation "revived" or re-presented after their disappearance from the field of consciousness appear fainter and less distinct the longer the time that has elapsed between their exits and their re-entrances. Nobody hesitates to regard such obliviscence as a psychological fact ; why, then, should we hesitate to suppose that presentations, even when no longer intense enough directly to influence attention, continue to be presented, though with ever lessening intensity?
On the whole we seem justified in assuming three grades of consciousness thus widely understood(1) a centre or focus of consciousness within (2) a wider field, any part of which may at once become the focus. Just as insight, surrounding the limited area of distinct vision on which the visual axes are directed, there is a wider region of indirect vision to any part of which those axes may be turned either voluntarily or by a reflex set up by the part itself, as happens, e.g., with moving objects quite on the margin of vesion. But in describing (3) subconsciousness as the third grade, this simile, due to Wundt, more or less forsakes us. Presentations in subconsciousness have not the power to divert attention, nor can we voluntarily concentrate attention upon them. Before either can happen the subconscious presentations must cross the threshold of consciousness, and so cease to be subconscious; and this, of course, is far from being always possible. Now in the case of sight an object may fail to catch the eye, either because, thought within the field of sight, it is too far away to make a distinct impression or because it is outside the field altogether. But we cannot conveniently interpret "threshold of consciousness" in keeping with the latter alternative ; mere accretion from without is a conception as alien to psychology as it is to biology. We must make the best we can of a totum objectivum differentiated within itself, and so are confined to the first alternative. Our threshold must be compared to the surface of a lake and subconsciousness to the depths beneath it, and all the current terminology of presentations rising and sinking implies this or some similar figure.
This hypothesis of subconsciousness has been stragely mis-understood, and it would be hard to say at whose hands it has suffered most, those of its exponents or those of its opposite. In the main it is nothing more than the application to the facts of presentation of the law of continuity, its introduction into psychology being due to Leibnitz, who first formulated that law. Half the difficulties in the way of its acceptance are due to the manifold ambiguities of the word consciousness. With Leibnitz consciousness was not coextensive with all physical life, but only with certain to higher phases [Footnote 48-1] of it. Of late, however, the tendency has been to make consciousness cover all stages of mental development and all grades of presentation, so that a presentation of which there is no consciousness resolves itself into the manifest contradiction of an unpresented presentationa contradiction not involved in Leibnitzs "unapperceived perception." Moreover, the active form of the word "conscious almost unavoidably suggests that an "unconscious mental modification" must be one in which that subjective activity, variously called consciousness, attention, or thinking, has no part. But such is not the meaning intended when it is said, for example, that a soldier in battle is often unconscious of his wounds or a scholar unconscious at any one time of most of the knowledge "hidden in the obscure recesses of his mind." There would be no point in saying a subject is not conscious of objects that are not presented at all ; but to say that what is presented lacks the intensity requisite in the given distribution of attention to change that distribution appreciably is pertinent enough. Subconscious presentations may tell on conscious lifeas sunshine or mist tells on a landscape or the underlying writing on a palimpsestalthough lacking either the difference of intensity or the individual distinctness requisite to make them definite features. Even if there were no facts to warrant this conception of a subliminal presentation of impression and ideas it might still claim an a priori justification. For to assume that there can be no presentations save such as pertain to the complete and perfect consciousness of a human being is as arbitrary and as improbable as it would be to supposein the absence of evidence to the contrarythat there was no vision or audition save such as is mediated by human eyes and ears. Psychological magnification is not more absurd than physical, although the processes in the two cases must be materially different ; but of course in no case is magnification with out limit. The point is that, while we cannot fix the limit at which the subconscious becomes the absolutely unconscious, it is only reasonable to expect beforehand that this limit is not just where our powers of discrimination cease.
Over and above hindrances to its acceptance which may be set down to the paradoxical and inaccurate use of the word unconsciousness, there are two material difficulties which prevent this hypothesis from finding favour. First, the prevailing objective implications of language are apt to make us assume that, as a tree remains the same thing whether it is in the foreground of a landscape or is lost in the grey distance, so a presentation must be a something which is in itself the same whether above the threshold of consciousness or below, if it exist, that is, in this lower degree at all. But it must be remembered that we are not now dealing with physical things but with presentations, and that to these the Berkeleyan dictum applies that their esse is percipi, provided, of course, we give to percipi the wide meaning now assigned to consciousness. The qualitative differences of all presentations and the distinctness of structure of such as are complex both diminish with a diminution of intensity. In this sense much is latent or "involved" in presentations lying below the threshold of consciousness that becomes patent or "evolved" as they rise above it. But, on the other hand, the hypothesis of subconsciousness does not commit us to the assumption that all presentations are by their very nature imperishable : while many modifications of consciousness sink only into obliviscence, many, we may well suppose, lapse into complex oblivion and from that there is no recall. Secondly to any one addicted to the atomistic view of presentations just now referred to it may well seem incredible that all the incidents of a long lifetime and all the items of knowledge of a well-stored mind that may possibly recur"the infinitely greater part of our spiritual treasures," as Hamilton sayscan be in any sense present continuously. The brunt of such an objection is effectually met by the fact that the same presentation may figure in very various connexions, as may the same letter, for examples, in many words, the same word in many sentences. We cannot measure the literature of a language by its vocabulary, nor may we equate the extent of our spiritual treasures as successively unfolded with the psychical apparatus, so to say, into which they resolve. [Footnote 48-2]
The attempt has more than once been made to avoid the difficulties besetting subconsiousness by failing back on the conceptions of faculties, capacities, or dispositions. Stored-up knowledge, says J. S. Mill, "is not a mental state but a capability of being put into a mental state"; similarly of the cases which Hamilton records, "in which the extinct memory [?] of whole language was suddenly restored," he says, "it is not not the mental impressions that are latent but the power of reproducing them." But surely the capability of being put into a mental state is itself a mental state and something actual, and is, moreover, a different something when the state to be reproduced is different. If not, how is such capability ever exerted? Even where the capability cannot be consciously exerted, must there not still be something actual to justify the phrase latent power? The "exaltation" of delirium may account for the intensification but not for the contents of the "extinct memories" which its unwonted glow reveals. It seems extraordinary that Mill of all men,and in psychology of all subjects, should have supposed such merely formal conveniences as these conceptions of faculties and power could ever dispense us from further inquiry. It might be urged in Mills defence that he has investigated further and concludes that the only distinct meaning he can attach to unconscious metal modification is that of unconscious modification of the nervesa modification of the nerves, that is to say, without any psychical accompaniment. But, while we can frequently understand a psychical fact better if we can understand its physical counterpart, a physiological explanation. If all we have to deal with are nervous modifications which have no psychical concomitants, then so far there is nothing psychological to explain ; but, if there really is anything calling for psychological explanationand this Mill does not denythen physical accompaniments must admit of psychical interpretation if they are to be of any avail. And in fact, although Mill professes to recognize only unconscious modifications of nerves, he finds a psychological meaning for these by means of his "mental chemistry,"a doctrine which has done its work and which we need not here discuss.
The exposition of subconsciousness given by Wundt is in the main an advance on that of Mill and calls for brief notice. Presentations, says Wundt, [Footnote 48-3] are not substances but functions, whose physiological counterparts in like manner are functional activities, viz., of certain arrangements of nerve-cells. Consciousness of the presentation and the nervous activity cease together, but the latter leaves behind it a molecular modification of the nervous structure which becomes more and more permanent with exercise, and is such as to facilitate the recurrence of same functional activity. A mere precise account of these after-effects of exercise is for the present unattainable ; nevertheless Wundt regards it as obvious that they are no more to compared to the activity to which they predispose than the molecular arrangement of chlorine and nitrogen in nitric chloride is to be compared to the explosive decomposition that ensues if the chloride is slightly disturbed. Mutatis mutandis, on the psychological side the only actual presentations are those we are conscious of as such ; but presentations that vanish out of consciousness leaves behind psychical dispositions tending to renew them. The essential difference is that, whereas we may some day know the nature of the physical disposition must of necessity be for ever unknown, for the threshold of consciousness is also the limit of internal experience. The theory thus briefly summarized seems in some respects arbitrary, in some respects ambiguous. It is questionable, for instance, whether the extremely meagre information that physiologists at present possess at all compels us to assume that the "physical disposition" of Wundt cannto consist in a continuous but much fainter discharge of function. At all events it is quite beside the mark to urge, as he does, that the effect of training a group of muscles is not shown in the persistence of slight movements during intervals of apparent rest. [Footnote 48-4] The absence of molar motions is no evidence of the absence of molecular motions. And it is certain that psychologically we can be conscious of the idea of movement without the movement actually ensuing, yet only in such wise that the idea is more apt to pass over into action the intenser it is, and often actually passes over in spite of us. Surely there must be some functionally activity answering to this conscious presentation, and if this amount of activity is possible without movement why may not a much less amount be conceived possible too? Again, what meaning can possibly be attached to a psychical disposition which is the counterpart, not of physical changes, but of an arrangement of molecules? Compared with such an inconceivable unknown, the perfectly conceivable hypothesis of infinitesimal presentations so faint as to elude discrimination is every way preferable. In fact, if conceivability is to count for anything, we have, according to Wundt, no choice, for "we can never think as retaining the properties it had when in conscious." None the less he holds it to be an error "to apply to presentations themselves a style of conception that has resulted from our being of necessarily confined to consciuousness." Verily, this is phenomenalism with a vengeance, as if presentations themselves were not also confined to consciousness!
48-1 The following brief passage from his Principes de la Nature et de la Grace (§ 4) shows his meaning:"Il est bon de faire distinction entre la Perception, qui est l´état intérieur de la Monade representant les choses externes, et lApperception, qui est la Conscience, ou la connoissance réflexive de cet état intérieur, laquelle nest point donnée à toutes les âmes, ni toujours à la même âme. Et cest faute de cette distinction que les Cartésiens ont manqué, en comptant pour rien les perceptions dont on ne sapperçoit pas, comme le peuple compte pour rien les corps insensibles" (Op. Phil., Erdmanns ed., ii. p. 715).
48-2 Much light may be thrown on this matter and on many others by such inquiries as those undertaken by Mr Francis Galton, and described in his Inquiries into Human Faculty, pp. 182-203.
48-3 Physiologische Psychologie, p, 203 sq.
48-4 J. S. Mill adopt substantially the same line of argument: "I have the power to walk across the room, though I am sitting in my chair; but we should hardly call this power a latent act of walking " (Examination of Sir W. Hamiltons Philosophy, 3rd ed., p. 329).
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