PSYCHOLOGY 



473 



be only different aspects of the same ultimate 

 existence), but the characteristic nature of the 

 mental fact is not readied by the most thorough 

 investigation of its physiological conditions, while 

 the latter are in many cases much more obscure 

 than the phenomena they are adduced to explain. 

 In the third place, an attempt has been made 

 (sometimes apart from any philosophical hypo- 

 thesis as to the nature of mind) to start with 

 certain mental facts called presentations, sensa- 

 tions, or feelings regarded as ultimate or inde- 

 pendent, and to trace the laws and manner of their 

 combination and succession. This method has 

 been worked with excellent result by the English 

 Associationist psychologists. By a similar method, 

 and by treating presentations as forces, Herbart 

 and his followers nave elaborated a mechanism of 

 the mind and reduced psychology to mathematical 

 form. The difficulty of this mode of conceiving 

 mind is to explain how a series of sensations or 

 any interaction of presentations can generate the 

 consciousness of a self persisting through changing 

 states ; and even to give any meaning to sensation 

 or presentation without regarding it as experienced 

 by or presented to mind. On these grounds many 

 psychologists, while influenced by the scientific 

 method of the Associationiste and of Herbart, hold 

 that presentation or sensation is only conceivable 

 as belonging to a subject or mind. So far, mind 

 must 1 assumed by the psychologist as implied in 

 the experience of which he has to trace the develop- 

 ment. This subject, or mind as the condition of 

 experience, may be admitted to elude psychological 

 observation. As Hume says : ' I never can catch 

 myself at any time without a perception, and 

 never can observe anything but the percep- 

 tion' Le. it is the empirical ego, or mind with 

 it- content of experience, which is the object of 

 psychological observation. But the pure ego, or 

 subject, is nevertheless implied by every mental 

 fact. Psychology may, in this way, be distin- 

 guished from other sciences as dealing with sub- 

 jective facts, or, rather, with the subjective aspect 

 which belongs to all facts i.e., as Dr J. Ward puts 

 it, with the phenomena connected with presenta- 

 tion to a subject. 



Method of Psychology. If this view of the 

 subject-matter of psychology be adopted, it is 

 clear that the ultimate source of our knowledge 

 of mental facts must be the knowledge each person 

 has, through self-consciousness, of his own mental 

 states. The mental attitude of attending to these 

 states is called Introspection. The nature and 

 value of introspection have been much disputed. 

 But the arguments of Cpmte and others to show 

 that the process is impossible, and psychology only 

 another name for a department of physiology, prove 

 too much : for were introspection impossible we 

 should not even know that there are such things 

 as mental states. It may I" 1 admitted, however, 

 that the introspective attitude involves an effort 

 of reflection which modifies the mental state we 

 'seek to observe. Consequently many obscure ele- 

 ments of mental life may elude its cognisance, and 

 only become known through their effects upon the 

 flow of ideas ; while, on the other hand, states of 

 intense mental concentration exclude it, and can 

 only be observed introspectively in the weakened 

 form of memory-images. It is even held by many 

 writers that this is the sole method of introspective 

 observation : that all introspection is retrospection. 

 In this way the results of introspection are apt to 

 lack accuracy, and ( as each observer is limited to 

 his own consciousness) they also lack objective or 

 universal validity. To supply these wants the 

 introspective or subjective method has been supple- 

 mented by objective observation both of the pnysi- 

 tlogical antecedents and concomitants of mental 



facts, and of the expressions, products, and records 

 of conscious life. The latter are to be found in the 

 emotional expressions and actions of normal men ; 

 in the emotional expressions and actions of children, 

 undeveloped races, the insane, and the lower ani- 

 mals ; in language ; and in social customs and 

 institutions. To this side of psychological study, 

 which involves the application of the comparative 

 method to psychology, contributions of the greatest 

 value have been made in the Zeitschrift fur Volker- 

 psycholoqie und Sprachwissenschaft, edited by Laz- 

 arus and Steinthal. Further, within recent years 

 attempts have been made to apply experimental 

 methods to psychology. Experiments on reaction- 

 time, for instance i.e. on the time taken to react 

 upon stimuli lead to the determination of the time 

 taken up by mental operations of different kinds 

 and different degrees of complexity. Similar ex- 

 perimental methods have been adopted for inves- 

 tigating the accuracy of reproduction, the number 

 of things that can be attended to at a time, &c. 

 Laboratories, such as that at Leipzig, of which 

 Wundt is the head, exist both in Germany and in 

 America for the prosecution of these experimental 

 investigations. The results of many experiments 

 have already been recorded ; but "it would be 

 premature at present to estimate the value of these 

 results for the science of psychology. Amongst 

 the experimenters who keep the bearing of their 

 investigations always in view, mention should be 

 made of Munsterberg (Beitrdge zur experimentellen 

 Psychologic, 1889 and following years ). 



Psycho-physics. The experimental inquiries 

 above referred to may to a large extent be traced 

 to certain investigations (chiefly) of E. H. Weber's 

 on minima sensibilia and on the relation between 

 the intensity of the sense-stimulus (which can be 

 measured objectively) and the intensity of the 

 consequent sensation (which cannot be directly 

 measured ). His experiments were further carried 

 out and their results formulated and elaborated 

 into the science of psycho-physics by G. T. Fechner 

 (Elemente der Psychophysik, I860 ; reprinted 1889). 

 By psycho-physics Fechner means the exact science 

 of tfie relations between body and mind, this science 

 being based upon facts and the mathematical 

 relations they involve. The generalisation arrived 

 at from experiment is by Fechner called Weber's 

 Law, and expressed by him in the following 

 (amongst other) terms: There will be the same 

 sensible difference of intensity between two sen- 

 sations, provided the relative intensities of the 

 stimuli producing them remains the same. Thus, 

 an increase of 1 to a stimulus whose strength is 

 expressed by 100 will be experienced as of the 

 same intensity as an increase of 2 to a stimulus 

 whose strength is 200, or of 3 to a stimulus whose 

 strength is 300, &c. The literature of psycho- 

 physics is occupied with the experimental verifi- 

 cation, the mathematical development, and the 

 interpretation of this law. But neither its experi- 

 mental basis nor its interpretation is quite satis- 

 factory. Experiment supports it only within a 

 certain range of sensibility. It is limited first of 

 all by what Fechner calls the 'fact of the thresh- 

 old ' i.e. the fact that a certain amount of 

 stimulus is required to produce any sensible effect 

 whatever ; and secondly, at the other end of the 

 scale, when the stimulus is beyond a certain in- 

 tensity, the relation ceases to hold good, while 

 within these two limits its verification cannot be 

 said to be exact. Further, it is only in the sense 

 of pressure and the muscular sense that we can 

 accurately measure the intensity of the stimulus 

 in the form in which it reaches the nervous end- 

 organs ; in hearing and sight the objective stimuli 

 undergo physical or chemical changes in the sense- 

 organ before reaching the extremities of the nerve- 



