FUNCTION OF ATTENTION.

79

This biological view of the function of attention suggests that our internal life is bound up with mental progress or development. It is only as we acquire new experiences, knowledge, and powers that our mental activity is kept at full tension. Accordingly when life becomes wholly or almost wholly a thing of routine, as in the case of the uneducated and still more of the old, it necessarily grows less conscious. It follows further that those who to special readiness in mastering and reducing by practice to a customary semi-conscious form add an abundant interest in new acquisitions (as Goethe) will have the richest conscious experience. By rapidity and perfection of adjustment they liberate more power for new adjustments, and their rich and varied interests continually prompt them to such new adjustments.1

REFERENCES FOR READING.

On the Analysis or Division of Mind and its Constituent Functions, see Hamilton, Lectures, i. lect. xi.; Bain, The Senses and the Intellect, Introduction; Ward, art. "Psychology," Encyclop. Britann. p. 39 ff.; Lotze, Microcosmus, i. book ii. ch. ii.; Höffding, Psychology, iv. The common tripartite division of psychical function is dealt with historically and critically by Drobisch, Empirische Psychologie, 5er abschnitt ii.; Brentano, Psychologie, 5er cap.; Wundt, Physiol. Psychologie, Einleitung, 2.

1 Cf. what was said above, p. 56 f. The fact here insisted on, that distinct consciousness occurs only as the concomitant of incomplete, that is, not fullyorganised nervous adjustments, suggests a teleological view of the function of consciousness as a factor in the life of the organism. According to this view, consciousness, with its discriminative and selective element, comes in as a modifying force in the chain of nervous processes where new lines of adjustive action have to be struck out. This question, however, necessarily raises the whole problem of the causal relation of psychical to nervous action, a problem that can only be profitably taken up later on. (See W. James, op. cit., i. p. 138 ff.)

CHAPTER V.

PRIMITIVE PSYCHICAL ELEMENTS.

§ 1. Elements, Processes, Products. In the preceding chapter we have distinguished between the ultimate constituents of Mind. These affective, intellective, and conative factors indicate different phases of the mental life and different directions of mental development. We have now to trace the development of each constituent, so far as this is possible, apart from the others, from its most rudimentary to its mature form.

This exposition of the threefold movement of development will necessarily begin with an account of the elements, or those simplest psychical phenomena with which the mental life of the individual begins. These are to be found, as already observed, in sensations and other simple phenomena closely conjoined with these. In the present chapter we shall be concerned with these. In a succeeding chapter we shall inquire into the processes by which these elements are combined into higher and more complex forms. At the outset we shall be concerned more especially with the processes of intellective elaboration already referred to. The development of feeling and of conation will be more readily understood when once the process of intellectual elaboration is mastered.

When we have thus grasped the elements with which we set out, and the processes of elaboration which they undergo, we shall be in a position to follow out the stages of production in the case of intellect, feeling, and conation. The working out of this part of the subject will fall into three distinct divisions.

This distinction of element, process of formation, and product which has grown common in recent works must be regarded as an artifice necessary for orderly exposition, but not corresponding to any real distinctions in our mental life. We know nothing of psychical elements which are not constituents of a process. A

PSYCHICAL ELEMENTS AND PROCESSES.

81

sensation, as ordinarily understood, e.g., a sensation of pressure, or of heat, is, strictly speaking, the result of a process of formation. Again what by an artificial abstraction we mark off as a product, e.g., an idea, is nothing but a completed process. Element, law of combination, product, are thus only three distinguishable factors or features in one and the same psychical event or process.

(A) SENSATIONS.

§ 2. Definition of Sensation. The term Sensation, as commonly used, has a certain ambiguity. In every-day language we apply the name to those simple mental affections which are connected with variations of bodily state, as sensations of cold, of hunger, of cramp. We hardly describe the mental effect of light, sound, and so forth, as sensations. Psychologists have long since extended the denotation of the term so as to include all the simple psychical phenomena arising immediately out of the action of the senses.

A sensation, being an elementary mental phenomenon, cannot be defined by being resolved into anything more simple. Its meaning can only be indicated by a reference to the nervous processes on which it is known to depend. Accordingly, a sensation may in a manner be defined as a simple psychical phenomenon resulting from the stimulation of the peripheral extremity of an afferent nerve when this is propagated to the brain (psychical centre or 'seat of consciousness'). Thus the stimulation of a point of the skin by pressure, or of the retina of the eye by light, gives rise to a sensation.

The more important of our sensations, these of the five senses, are produced by the action of some external agent, as pressure or light, on the end-organ. But it is not desirable to refer to this in our definition. In the case of many of our "organic" sensations, those due to changes in the vital processes, as hunger, thirst, there is no such external agent at work. The same applies to the "subjective sensations" of the special senses which in abnormal circumstances arise from a process of internal stimulation, e.g., the action of the congested capillaries of the retina on the optic nerve. The case of the so-called "muscular sensations" to be considered presently offers special difficulties to a comprehensive definition of sensation.

As already pointed out, a pure elementary sensation according to this definition is, so far as we know, non-existent, and is only postulated as a necessary starting-point. What seems a pure sensation to us in mature life when we begin to study it is really complicated by residua of past sensations, the result of rudimentary processes of assimilation and integration. Even if we could divest sensation of this representative element we should have the difficulty to be spoken of presently, that sensations which seem to introspection perfectly simple are known in many cases to be complex, the result of a coalescence of sensation-units.

This reference of sensations to their physiological antecedents and conditions enables us to deal with them at the outset. Although a distinct and vivid sensation, e.g., of a musical sound, is, as we shall see, determined in part by a simple mode of central reaction, it is primarily conditioned by the peripheral process of stimulation, and may be studied with advantage at the beginning under this aspect.

§ 3. Sensation and Sensibility. Another term correlative with Sensation must be referred to here, viz., Sensibility. This is the abstract term corresponding to the more concrete name sensation, and properly signifies the capacity of experiencing or being affected by sensations. It is to be noted that sensibility, like sensation, refers to the conscious effect, and not to the physiological process. It is true that we are wont to attribute sensibility to the portion of the organism in which the process of stimulation is set up, as the hand. But this is due to that unalterable habit of projecting and localising our sensations, the origin of which will be dealt with by-and-by. Strictly speaking, sensibility is not a property of the skin, or of the nerve, but of the mind, though of course the co-operation of these physiological structures is necessary to the maintenance of this sensibility.

We here come across a difficulty that meets us all through in dealing with the simpler psychical phenomena, viz., that of distinguishing the psychical from the closely-involved physical process. The same word often refers ambiguously to each. Thus, sense-impression means now the physical action going on in the retina when stimulated by light, now the mental result or sensation proper. Similarly the term movement means now the physical process, now the psychical accompaniment of this.

§ 4. Presentative and Affective Element in Sensation. If we examine our sensations we may, in most cases at least, easily distinguish two elements or aspects which clearly contrast one with another. Thus a sensation of taste, say that of a pear, has a particular character (or characters) by means of which we come to know what this sensation stands for, viz., the pear. This element may be called the intellectual element since it subserves cognition, or the presentative element inasmuch as it enters into the "presentations of sense" or sense-perceptions to be explained hereafter. But the flavour of a pear has a second and distinct aspect, viz., a pleasantness or agreeable

DEFINITION OF SENSATION.

83

ness, in consequence of which it is liked, prolonged, and desired. This is a properly affective element, and may be marked off as sense-feeling, that is to say, that elementary phase of feeling which is immediately involved in sensation. As we shall see presently, the relative proportion of these two elements varies greatly in the case of different classes of sensation.

Here, again, the need of clear verbal distinctions is greatly felt in psychology. The same term sensation has been commonly used to include the element of feeling as well as of presentation; and by some writers it has been used (as in common life) with a special reference to the affective aspect. By denoting this last by the special term sense-feeling we may use "sensation" to indicate the presentative side, or when we want to be more precise may mark this off as the presentative element.1

§ 5. General or Common Sensation: Organic Sense. All parts of the organism supplied by sensory fibres from the cerebrospinal system give rise to sensations. These fall into two main classes: Common or General Sensation, and Special Sensation. The former involve no special structure (end-organ) at the peripheral termination of the nerve-fibres, the latter do involve such a structure. The common sensations together make up what has been variously called the organic or the systemic sense.

Common sensation includes certain sensations which result from changes in the skin and the outer region of the body generally, including the special organs as the eye and the muscles, and also other sensations connected with the internal vital organs. The former include such sensations as those of tickling, tingling, shivering, certain muscular sensations, as cramp, and the painful sensations resulting from severe pressure and laceration of tissue. The organic skin sensations have to be carefully distinguished from the sensations of touch proper. The internal sensations are those which accompany special conditions, and particularly all disturbances, of the vital functions, as respiration, circulation, digestion. In this way arise such familiar sensations as tight-breathing, hunger, indigestion, local inflammation and heat, etc.

1 A like ambiguity is noticed in the abstract terms sensibility and sensitiveness which are used with reference to the presentative element and also to the element of feeling. On the different meanings of the term sensation, see Hamilton's Edition of Reid's Works, Note D. Cf. also J. Ward, article "Psychology" (Encycl. Brit.), p. 41, col. 2.

2 It is not certain whether the sensations of muscular fatigue should be included under organic sensations, or whether they belong to the class of special muscular sensations to be spoken of presently.