« PredošláPokračovať »
in the performing or process as an event. We can therefore think of an image as continuing the work of a sense-impression. We have already considered how the repetition of a given senseimpression may continue the work of a previous impression. And just as we deny the existence of the first sense-impression during the interval between its occurrence and the occurrence of another impression of the same kind having the same function, so we deny the existence of an image when not actually occurring.
What then is a memory-image ? Whence comes it? It is not 'given as the sense-impression is given, and it is not the persisting vestige of the sense-impression. To arrive at the answer we may turn to the consideration of what seem at first sight kindred facts; viz., after-images and recurrent sensations. After-sensations or after-images are probably the supposed justification for conceiving of memory-images as
differing only in degree from sense-impressions, whereas in our Vopinion they differ fundamentally in kind. After-sensations
are lingering sense-impressions whose being as events can be regarded as independent of any other process in the life of the individual. They are 'given', and occur under the same general conditions of stimulation as sense-impressions. In the case of recurrent sensations, however, the above dictum requires some modification. Although the same conditions of stimulation are necessary, there are needed in addition certain features in mental life itself, notably, the absence of any strong conative tendency in relation to present sense-impressions. Recurrent sensations arise when the individual is at a loose end, frequently when he is ready for sleep. Their occurrence is due to two sets of conditions ; in so far as they require strong original sense-impressions and will only occur when these have been given, they are of the nature of after-sensations, but in so far as they depend upon the presence of certain conditions in the stream of consciousness, they are akin to the memory-image proper. It is within
mental life that we must seek the essential conditions of the latter.
Memory is cognition of something known before. The particular memory is in continuity with the former knowing. The former knowing was occasioned by sense-impressions ; the image continues the work of the former sense-impressions. Since this continuity is not occasioned by a repetition of the sense-impressions, it can only occur as an event because it is required' by the character of the mental processes themselves. We may say that it stands to those processes in a partto-whole relation, although we can only trace out the relation in terms of function. To take the simplest case of imagery, the imagery occurring in sense-perception; we have said that sense-impressions could be integrated into an organic unity by conation, a unity, that is, wherein any part is relative to the whole and implies correlate parts. That unity of sense-qualities with the same spatial reference, which constitutes a sense-thing, is an instance of such an integration. When one or more of these qualities are known on the occurrence of sense-impressions, others can be known by imagery. The child who' opens his mouth and shuts his eyes to see what the king will send him ', may visualize the tasted peppermint. Such imagery is occasioned by the given sense-impression as its complement; it is required' or provoked by the cognitive function of those given processes. Sight and touch in particular illustrate this reinforcement of impression by imagery. Similarly, when conation has linked sense-perception with sense-perception in the fulfilment of its endeavour, when they have entered as parts into the furtherance or frustration of striving, and thereby have come into organic connexion one with another, the occurrence of one sense-perception will require the other as its complement. If the one be 'given ', in the sense that the function of perceiving is sustained by sense-impressions, the unity of the whole will occasion the cognition of the others, and that cognition will be sustained
by imagery. The sight of his play-box may suggest to the child the idea of his absent play-mate. If we ask, then, 'what brings imagery into being ?’ the answer is, the nature of cognition and conation. Granted that one cognitive process can carry on the function of another of the same character as itself, granted that there are within mental life active processes of wanting, striving, the running of whose course brings about the relations of cognitive processes to one another and to conation, such that any one is incomplete in respect of the function of that conation without the others, then, if hereafter a part of this organization (or 'structure ') be given, and the processes necessary for its completion be not given, those processes will be reproduced in imagery. The organization of the whole requires this. There is here, as in the simpler cases already considered, persistence and continuity of function. The imagery does the work of senseimpressions and is an event in mental life just as a senseimpression is an event.
If we consider the points adduced in text-books of psychology as distinguishing images from sense-impressions, we shall see that they are such as we should expect from the conditions of the occurrence and the function of images. Their fragmentariness and lack of distinctness in contrast with sense-impressions is thus explicable. Only so much is required as will sustain cognition. That images should flicker in the manner described by Prof. Ward is also intelligible. Sense-impressions, as 'given ', may be more or less abiding; their function can be repeated, or maintained ; but the image vanishes when its function is performed. If I wish to recall my friend's face in detail, the image of the feature contemplated at each moment will be present, eyes, hair, mouth. To know the face as a whole in memory requires an effort. Fragmentariness will in part account for the lack of strength and forcibleness in images. Again, images occur against the background of organic sensations which are integrated with
present sense-impressions. It is but rarely that the organic sense-impressions are integrated with imagery in the cognition of the same object. When they are, the object known is confused with an object of perception; e. g. in hallucination. The same is true of motor experiences; eye and hand movements, which are interwoven with sense-impressions in the cognition of X or Y, are not integrated with imagery in memory of the same. Since the cognition which is sustained by imagery is occasioned by the demand of the trend of cognitive and conative processes, there is not in the image the arresting character that there is in the sense-impression. The 'given’ can break across a train of cognition; it can be totally alien to it in character and function. In denying this character to images, it may seem as if the sudden memories that startle us have been overlooked, e.g. the stab of a forgotten message which is remembered à propos of nothing at the wrong time. No doubt such memories occur, but their irrelevance is apparent rather than real, and their further consideration can be postponed until a later section.
How far this view of an image as a process in the life history of the individual due to continuity of function in the sense of work, is identical with Prof. Stout's doctrine of psychical dispositions, the writer is uncertain. It is obvious how much use has been made of his conception of conative unity'. ' Disposition' is apt to suggest a state of an existent something which persists between its manifestations, just as a muscular disposition built up by practice in rowing may be said to exist in one's arm between one practice time and another.
With Prof. Ward's view of subconsciousness and with his account of the memory-image, the writer has found difficulties. The primary difficulty lies in understanding the nature of a 'presentation '. The 'totum objectivum ' as 'there', 'presented', is within the experience of the individual. Pre
sentations are parts of this 'totum objectivum ', picked out by the selective activity of the subject. They are said to stand in relation to one another and to the subject. What is not clear is whether a presentation is regarded as 'what is known'. Granted that 'what is known' is a psychological object, and as such is in relation to an individual knower, 'what is known 'is nevertheless not treated as a mental process, yet it would seem that only presentations in the sense of processes could enter into the temporal march of an individual's experience.
When Prof. Ward speaks of the plasticity of the presentation-continuum, his teaching may be made applicable to sense-impressions as processes, or to the objects known by the subject when the processes take place. Yet when Prof. Ward asks, 'what is it that persists ?' and replies, ‘On our theory we must answer, the continuum as differentiated, not the particular differentiation as an isolated unit ' (Psychological Principles, p. 81), the stress appears to be on the individual's world as known, rather than on the occurrences within his ever-changing experience. The account of the involution and evolution of images is particularly baffling. Like Sir W. Hamilton, Prof. Ward makes use of the conception of subconsciousness and gives it a double significance. It stands for the field of the 'given 'which at any moment is 'beyond’ the subject's attention, a shadowy border-land from whence a this may be now within, now without experience. But it also stands for a realm of images, and this would seem to imply that images are persistent entities. Prof. Ward faces the difficulty which confronted Hamilton : Do all experiences persist ? and whereas Hamilton solved the puzzle by allowing some experiences to decline into impotence under the pressure of others, Prof. Ward solves it by making one and the same image do duty for several ideas. An image is compared to a word in a concordance, which although it appears but once, stands in many references. The Herbartian