CHAP. IV. Subject introduced. CHAPTER IV. REPRESENTATION. SECTION I. CONDITION OF REPRESENTATION. § 90. We have already seen that in the process of the acquisition of presentative knowledge there is found mixed up with it a great deal of what is only representative. Our perception of any external object is a complex of presentative and representative elements, of actual and ideal sensations. Thus, in the acquisition of knowledge, there is involved the possibility of presenting the elements of the knowledge already acquired. This power of representation is of great importance, apart altogether from its being subsidiary to the perceptive process, so that we must devote special attention to it. By far the greatest part of our knowledge can be brought before consciousness only in a represented state; and all the higher operations of the mind depend upon representation as a condition of their possibility. Before entering upon a consideration of the laws and kinds of representative knowledge, we must first give heed to the question, how is representation possible? What are the conditions upon which the representing in consciousness of forgotten knowledge depends? Sensations, once felt, disappear from consciousness; knowledge, once obtained, whether very simple or very complex, drops into oblivion. After a long time the sensation may be more or less vividly revived, the knowledge more or less completely restored. In the interval it has been completely out of the sphere of consciousness. In its represented state, its original cause, the object of presentative knowledge, is not present. The question is, how is the knowledge revived without the assistance of its original object? How is the sensation repeated without the concurrence of its original external cause? As the objective cause of the recurrence of actual sensations in regular groups and order has been called the permanent possibility of sensations, so we might here speak, and with better reason, of the permanent possibility of phantasms or ideas as being the condition of represented knowledge. But the truth is that, in both cases, the permanent possibility is the very fact to be explained, and the mere statement of the fact is not the explanation of it. The general fact, then, which we know regarding this subject, is the permanent possibility of becoming conscious of phantasms or revived sensations. CHAP. IV. SECT. I. tion hypo § 91. The explanation of this fact is a problem of Explanavery considerable difficulty. There is no extra-thetical. organic object necessary to aid in the recall of forgotten knowledge. Sensations and perceptions, when forgotten, are altogether beyond the ken of consciousness. There are therefore no direct means of SECT. I. theses. CHAP. IV. observing the condition of the possibility of their recall. Consequently, as far as psychology is concerned, the explanation must be hypothetical. The Two hypo- hypotheses which have been proposed in explanation of the problem are two in number. The condition of the permanent possibility of phantasms may be mental, or it may be organic; in the former case, we have the hypothesis of latent mental modification; in the latter, that of unconscious cerebration. the respective claims and difficulties of these two conflicting hypotheses we may give some attention. Mental latency. To § 92. The doctrine of latent mental modifications has been already referred to,* as an attempt to analyse sensations into unconscious elements, and in that connection we saw reason to reject it. As an explanation of the permanent possibility of phantasms or ideas it is open to some of the same objections as before. It postulates that the mind is capable of retaining within itself certain latent activities which are lying ready to spring up into conscious life whenever the occasion requires. But we have already noticed the objection against calling anything mental which cannot be observed by consciousness. If, however, we admitted the theory of idealism to be true, this objection would fall to the ground. That theory explains the actual sensations which are the elements of perception as the result of an objective mental cause; and consequently it could have no objection to explain the permanent possibility of revived sensations by a mental cause. But if we wish to retain the distinction between activities which are mental and powers which are not mental, and if we explain the latter as powers which originate and operate beyond the sphere of consciousness, we must reject the doctrine of mental latency. This distinction and explanation, which characterise philosophical dualism as opposed to idealism, appear to us to correspond to the truth of things, and, therefore, we must seek elsewhere for an explanation of the permanent possibility of phantasms and ideas. CHAP. IV. SECT. I. § 93. The mental hypothesis being rejected, the Cerebral hypothesis. only other possible hypothesis must refer us to some non-mental explanation of the difficulty; unless, indeed, we take refuge in some supernatural explanation of it—which, however, would in the present day scarcely be thought scientific. And as all realists or dualists admit a physical cause for their actual sensations, they can consistently offer no objections to the explanation of revived sensations by a nonmental cause. But as ex hypothesi there is no extraorganic object, the non-mental cause, if such there be, must be an organic one. The examination of this hypothesis is therefore transferred from the hands of the psychologist to those of the physiologist, and the latter presents us with his theory of unconscious cerebration. In the hypothesis it is assumed that every sensation which has come into consciousness has been preceded and caused by some molecular movement in the substance of the brain; it is assumed that the repetition, or continuance, of a cerebral activity, CHAP. IV. SECT. I. occasioned by continued attention to the conscious feeling of which it is, the antecedent, will have the. effect of making a permanent change upon the nervous tissue, and thus of registering, as it were, the original activity, so that it may be easily repeated. It is assumed, farther, that in the complex net-work of nervous centres which constitutes the cerebrum, there is such a connection that any activity propagates itself from one centre to another, and to many others, and that this cerebral activity may either excite conscious sensations or not, according to circumstances. Here, then, we have all the essential elements of the hypothesis. There are, in the nervous tissue of the cerebrum, permanent registrations of forgotten feelings; permanent nerve cells or clusters of cells produced or modified by some past activity; and these explain the permanent possibility of forgotten sensations being revived. Into the details of the hypothesis we cannot at present enter, but offer the following remarks regarding its difficulties and Difficulties § 94. There is no possibility of observing directly the correspondence between conscious sensations and nervous activity. Neither is there any possibility of observing any changes which may take place in the nervous tissue of the cerebrum; and if there were, it could not be said that these changes are the result of sentient activity. The evidence upon which the hypothesis is built is of a very indirect and obscure kind, * Those who wish to pursue the subject farther are referred to the writings of Herbert Spencer, Dr. W. B. Carpenter, and Prof. Bain. |