PSYCHOLOGY 



475 



The earliest stage of mental life would rather seem 

 to be a vague manifold into which distinction is 

 just being brought ; and the growth of knowledge 

 consists not only in the addition of new elements, 

 but in drawing new lines of distinction and forming 

 new groupings of elements. And these distinc- 

 tions and groupings may be said to be determined 

 by the varying intensities of different elements in 

 the changing mental content, or by the continuous 

 redistribution of attention. 



Ideation. The mental content thus varies in the 

 distinctness of its parts, which may even disappear 

 from consciousness and afterwards reappear. This 

 reinstatement in consciousness is called Represen- 

 tation or Ideation, and the represented or ideal 

 contents are called Images. The circumstances 

 determining the succession of ideas and forma- 

 tion of images are, first, new sense-impressions; 

 secondly, voluntary direction of attention ; and 

 thirdly, the mutual influence of the mental 

 elements. It is the last of these which is referred 

 to under the title of Laws of Association. In 

 the article ASSOCIATION OF IDEAS an account is 

 given of the way in which one concrete experience 

 recalls another. In every case of association a 

 twofold process would seem to be involved. A 

 portion of the present mental content coalesces 

 with a resembling portion of a past mental state, 

 and the revival of this portion involves the re- 

 instatement in consciousness of the other elements 

 with which it was previously connected. The 

 latter, which is the properly reproductive process, 

 is thus due to the fact that consciousness is not a 

 collection of atomic sensations, but a continuous 

 whole. 



Perception is the knowledge by means of sensa- 

 tion of an individual object or thing. The nucleus 

 of the percept is thus one or more present sensa- 

 tions which coalesce with revived or ideal elements 

 belonging to the same sense, and combine with 

 revived or ideal elements belonging to other senses. 

 These presentative and representative elements are 

 bound together and presented as a single mental 

 content, which we refer to a portion of the body or 

 to a thing in space l>eyond the body, and to which 

 we ascribe qualities corresponding to our sensa- 

 tions. In brief, Perception, as distinguished from 

 Sensation, involves, first, complexity of elements ; 

 secondly, localisation ; and thirdly, individualisa- 

 tion and objectification. The complexity consists 

 of the elements of present sensation, and of the 

 ideal group with which the former coalesce or com- 

 bine. The localisation clearly involves the percep- 

 tion of space. The individualisation and objectifi- 

 cation may be accounted for by the following con- 

 siderations : ( a ) The various sensations grouped 

 together in a percept e.g. the resistance, touch, 

 colour, taste, smell of an orange are so related 

 that modification of one of them commonly involves 

 modification of the others. Thus they come to be 

 |>erceived as a group, {b) Not only are motor sen- 

 Hations involved in fixing attention on other sensa- 

 tions, but the greatest distinctness of the other 

 sensations is commonly accompanied by conditions 

 which admit also of sensations of touch and resist- 

 ance. Hence the object comes to be experienced 

 as offering resistance or as an obstacle, (c) In this 

 way the other sensations come to suggest touch 

 ana resistance, and thus to be referred to a thing 

 in space which offers resistance to our muscular 

 energy. This forms the psychological basis of 

 the distinction between primary and secondary 

 qualities of matter. 



The above account traces the perception of 

 objects in so far as it is mainly dependent upon 

 active touch i.e. touch plus its attendant motor 

 sensations. To active sight i.e. sight plus its 

 attendant motor sensations a perception u due 



which differs from the preceding (a) in the absence 

 of the sensation of resistance : so that we do not 

 derive from active sight alone a knowledge of 

 objects outside of and opposed to our own bodies, 

 and our apparently direct perception of distance, 

 solidity, &c. by sight is really a derived percep- 

 tion ; (b) in the vastly greater number of elements 

 simultaneously presented, so that the simultaneity 

 of perception which characterises the developed 

 perception of space is mainly due to visual percep- 

 tion. 



Space and Time. As the preceding paragraph 

 points out, objects or things are perceived as in 

 space. Similarly, our conscious life is apprehended 

 as a succession i.e. as in time. The whole of our 

 experience may thus be said to be conditioned by 

 Space and Time : the phenomena of external per- 

 ception by space, those of internal perception by 

 time. The two spheres are sometimes described as 

 the object- world and the subject- world respectively. 

 Regarding both space and time there are several 

 questions which admit of being kept distinct. 

 First of all, there is the question as to their reality 

 are they real existences, or simply modes of our 

 subjective perception ? This is a question which 

 properly lies outside psychology, and belongs to 

 metaphysics. Then there is the question of the 

 way in which we form concepts of space and 

 time. Geometry depends upon such a conception 

 of space. The points, lines, and surfaces of geo- 

 metry are not percepts, but abstractions from per- 

 ception, formed as other concepts are formed. 

 \\ hat then is that in perception from which we 

 are able to form concepts of space and time ? It 

 must itself be a spatial or temporal percept. It is 

 then with regard to the perceptions of space and 

 time that the most difficult psychological question 

 enters. And the question regarding both per- 

 ceptions is affected by the secular controversy 

 concerning the existence and the function of an 

 (i jiriiiri factor in mind. 



Thus we start with two opposed views of the 

 perception of space : first, the Intuitive or Nativist 

 theory, according to which space is an innate idea 

 (or, as since Kant it has more commonly been put, 

 is the form in which we perceive objects), and is 

 not derived from sensations, but is a form of per- 

 ceiving, belonging a priori to the mind, and con- 

 tributed by it in the production of experience ; 

 secondly, the Empirical theory, according to which 

 space is the worked-up product of sensations. The 

 universal and necessary character of the spatial 

 perception has been brought forward in defence of 

 the former theory. But it is important to remem- 

 ber that certain sensations odours, tastes, and 

 even sounds are localised only indirectly, as be- 

 longing to a visible or tangible object. And this 

 fact at once suggests the lines upon which an 

 empirical analysis of space should be carried out. 

 By Herbart space has been derived from a series 

 of sensations which can be repeated in the same 

 and in reverse order. By Bain it has been held 

 that it is due to muscular sensation movement 

 giving the perception of empty space, resistance 

 giving that of space tilled or body. Sensations 

 both of movement and resistance accompany touch ; 

 and sensations of movement accompany sight to an 

 extent which is not nearly equalled in the other 

 senses. In addition to this, however, we must 

 take account of what Lotze calls the ' local signs ' 

 which Ix'limg to tactual and visual sensations. 

 These local signs are due to the extended nature 

 of the sense-organs of sight and touch, and are 

 elements in sensation by which sensations arising 

 from the stimulation of different portions of the 

 retina (or of the skin) are distinguished from one 

 another. The simultaneous distinctness in sensa- 

 tion which is due to these ' local signs ' is gradually 



