338 



DISCOVERY 



endow the unconscious, like the conscious, with a 

 mental aspect. They convince him of the necessity for 

 displacing consciousness from the pinnacle it has hitherto 

 occupied in psychology. Unconsciousness is no longer 

 a mere " fringe " around the field of consciousness. It 

 becomes the basis, the foundation on which conscious- 

 ness depends — the nourishment from which it draws 

 its very existence. We begin to see the "superficiality " 

 of consciousness, and to recognise that almost any 

 mental event may happen with or without the accom- 

 paniment of personal consciousness. Such conscious- 

 ness has been evolved to facilitate choice between 

 alternative reactions — to bring the entire unity or 

 personality of the organism into more complete relation 

 with its environment. Where only one reaction is 

 fHJSsible, the action remains a reflex, and no sensation 

 or impulse need be felt. Where the reaction is to some 

 extent modifiable, the action becomes instinctive — 

 emotional activity, impulsive tendencies, and crude 

 blurred sensations being experienced. Where alterna- 

 tive responses are desirable, discrimination becomes 

 acute and a larger and more dominating self develops — 

 a dominating apical system which endeavours to permit 

 of action only after it has given its consent or sanction : 

 thus arise the beginnings of will. 



We now recognise that the consent and sanction of 

 the self to a volitional act are but the reaction of an 

 apical mental system to the sum total of conflicting and 

 favourable tendencies to action ; that every seemingly 

 unaccountable thought and action are traceable to a 

 " cause," and that the " reasons " offered by the self for 

 a course of thought or action are often mere illusory 

 explanations, unconsciously later coined as excuses for 

 actions and beliefs which in reality are dictated by the 

 lower and more fundamental conative tendencies of 

 instinct, emotion, unconscious suggestion, and very 

 early experience, working themselves out by their 

 own perseverating, " determining tendencies." These 

 changes of outlook mark an enormous advance in the 

 progress of psychology ; but we may well ask, what 

 immediate interest have they for physiology, how have 

 they been dictated by physiological know-ledge, and 

 how can they be absorbed into it ? 



The truth is that these modern developments of 

 psychology have taken place entirely independently 

 of physiological considerations. We have no idea of the 

 actual neural seat or of the physiological conditions of 

 consciousness. We do not even know what physio- 

 logical changes occur when a conscious act, by suffici- 

 ently repeated experience, becomes an unconscious 

 habit. There is no reason to suppose that we have 

 here a transference of physiological activity from higher 

 to lower neural levels. All our knowledge rather points 

 to the conclusion that under certain conditions con- 

 sciousness may be present, while under others it may 



be absent, when the same nervous areas are thrown into 

 activity. We have indeed no reason to believe that 

 the so-called sensory or sensori-p)sychic areas ' are the 

 " seats " of conscious activity at all, although these 

 centres are doubtless indispensable for its manifestation. 

 Just as, if trains must pass through a certain junction 

 to reach their ultimate terminus, we do not identify the 

 junction with the terminus, so we are not justified in 

 identifying cortical centres with the seats of conscious 

 activity. 



Physiology can offer no counterpart to the known 

 psychological facts of perseveration, of the irresisti- 

 bility of emotional force, or of its sublimation to higher 

 and stiU higher forms. Nor is she concerned in the 

 recognition of two main currents of psychical energy, 

 the one directed outwards towards the external world, 

 the other turned inwards and lost in the intricacies of 

 day-dreaming and concentration on internal experience. 

 These contrary currents of psycliical activity have re- 

 ceived the names of "extraversion " and "introversion "; 

 and the recognition of their difference and of their 

 pathological variations has thrown much light on the 

 psychology of functional nervous disorders and the 

 insanities. But for the phj-siologist they have, for the 

 present, at least, no meaning or interest whatever. 



Similarly devoid of expression in physiological 

 language are our conceptions of psychical " dissocia- 

 tion " and "regression "; the first, the splitting up of the 

 unified conscious stream into smaller, more or less 

 independent fragments, and the possibilities of co-con- 

 sciousness, i.e. the coe.xistence of t%vo or more such 

 fragments in the mind ; the second, the backward or 

 involutionary path of mental processes to more infantile 

 conditions. 



As I have already urged, the psychologist studies 

 mental processes for their own sake. His remarkably 

 detailed and elaborate researches into the conditions 

 of association — the rate of learning and forgetting, the 

 results of distributing a definite number of repetitions 

 over a longer or a shorter time, the effects of learning 

 a given quantity of matter by sectional or by entire 

 (global) repetitions, the temporary inhibiting or facili- 

 tating influences of subsequently learnt associations over 

 earlier ones, the apparent indcstructibiUty of (at least, 

 emotional) memories — are all investigations which the 

 psj'chologist has carried out and successfully applied 

 in practice, despite our utter ignorance of the physio- 

 logical basis even of memory. The analysis of the men- 

 tal work curve, e.g. the recognition, and the attempts 

 at measurement, of the opposing factors of practice, 

 fatigue, incitement, spurt, and settlement, the influence 

 of drugs on mental work, the relations of sensory ima- 

 gery and speech to thought and of meaning to imagery 



' Parts of the brain which are definitely associated with 

 sensation and perception. 



