Page:Catholic Encyclopedia, volume 12.djvu/616

 PSYCHOLOGY

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PSYCHOLOGY

to their original elements, determining as far as possible their organic conditions, and tracing the laws of their growth; (2) based on the results of this study, a rational theory or explanatory account of the nature of the agent or subject of these activities, with its chief properties.

Method of Psyclwlogy. — The primarj' method of investigation in empirical or phenomenal psychology is introspection or reflective observation of our own mental states. This is the ultimate source of all knowledge of mental facts; even the information gathered immediately f om other quarters has finally to be interpreted in terms of our own subjective ex- perience. Introspection is, however, liable to error; consequently, it has to be employed with care and helped and corrected by all the supplementary sources of psychological knowledge available. Among the chief of these are: the internal experience of other observers communicated through language; the study of the human mind as exhibited iu different periods of life from infancy to old age, and in different races and grades of civilization; as embodied in various languages and literatures; and as revealed in the absenc of particular senses, and in abnormal or pathological conditions such as dreams, hj'pnotism, and forms of insanity. Moreover, the anatomy, physiology, and pathology of the brain and nervous system supply valuable data as to the organic con- ditions of conscious states. Experimental psychology', psychophysies, and psychometry help towards ac- curacy and precision in the description of certain forms of mental activity. And the comparative study of the lower animals may also afford useful assistance in regard to some questions of human psychology'. By the utilization of these several som"ces of informa- tion, the data furnished to the psychologist by the introspective observation of his own individual mind may be enlarged, tested and corrected, and may thus acquire in a certain degree the objective and uni- versal character of the observations on which the physical sciences are built. Introspection is fre- quently spoken of as the subjective method, these other sources of information as supplementary ob- jective methods of psychological study.

Branches of Psychology. — Indeed some of them have rapidly grown to be such large and important fields of research that they now claim to be recognized as special departments of psychologj', or even sciences in their own right. Thus we have comparative psychology including animal psychology, child psy- cholog>-, and race psj'chology. Again psychiatry or psychopathology, the science of mental disease, also physiological psychology, which, in a broad sense, includes all systematic study of the organic conditions of mental life, or, as Ladd defines it, "psychology ap- proached and studied from the physiological side".

Experimental Psychology. — A special department of physiological psychology which has recently risen rapidly into favour in some countries is experimental psychology, alluded to above in our historical sketch. It is at times styled the "Xew Psychologj'" by its more enthusiastic supporters. It seeks to secure precision and an objective standard in the description of mental states by controlling their conditions by skilful devices and ingenious apparatus. Its chief success so far has been in its efforts to measure the varying intensity of sensations, the delicacy of sense- organs and "reaction-time" or the rapidity of a facul- ty's response to stimulation. Certain properties of memory have also been made the subject of measuring experiments and more recently considerable in- dustry has been devoted, especially by Kulpe and the Wiirzburg school, to bring some aspects of the higher activities of intellect and will within the range of the laboratory apparatus. Opinions still differ much as to both the present value and future prospects of ex- perimental psychology. Whilst Wundt, the leader

of the new movement for the past fifty years, places the only hope of psychological progress in the ex- perimental method, Wilham James's judgment on the entire hterature of the subject since Fechner (1840) was that "its proper psj'chological outcome is just nothing at all" ("Principles", I, 534). Apart, how- ever, from the very modest positive results, especially in the higher forms of mental life, which the experi- mental method has achieved or may achieve in the future, its exercise may ne^'ertheless prove a valuable agency in the training of the psj-chological specialist, both in increasing his appreciation of the value of the most minute accinacy in descriptions of mental states, and also by fostering in him habits of precision and skill in systematic introspection.

Classification. The Faculties. — In empirical psy- chology, with modern ^Titers, the next step after determining the method of the science is to attempt a classification of the phenomena of mental life. In the scholastic philosophy the equivalent operation was the systematic division of the faculties of the soul. Apart from vegetative and locomotive powers the Schoolmen, following Aristotle, adopted a bi- partite di\'ision of faculties into those of cognition and appetency. The former they subdivided into sen- suous, and intellectual or rational. The sensuous faculties they again subdivided info the five external senses and the internal acti\-ities of imagination, sensuous memorj', sensus communis, and vis cogita- tiva. But there was much disagreement as to the number, character, and boundary lines of these in- ternal forms of sensuous cognition. There were also divergences jf opinion as to the natiu-e of the faculties in general in themselves and to what extent there was a dislinctio renlis between faculties and the essence of the soul. But, on the other hand, there was general agreement as to an essential difTerence between all sensuous and intellectual or spiritual powers of the mind. The possession of the latter constitutes the differentia which separates man from the irrational animals.

Content of Empirical Psychology. — The psycholo- gist natiU'aUy begins with the treatment of the phenomena of sentiency. The several senses, their organic structiu'e and functions, the various forms of sentient activity with their cognitive, hedonic and appetitive properties and their special character- istics have to be carefully analyzed, compared, and described. Next, imagination and memorj' are similarly studied, and the laws of their operation, growth, and development diligently traced. The discussion of the organic appetites springing from sensations, and the investigation of the nature and conditions of the most elementary forms of pleasure and pain may also appropriately come here. In- tellect follows. The consideration of this faculty includes the study of the processes of conception, judgment, reasoning, rational attention, and self- conscious reflection. These, however, are all merely different functions of the same sjiiritual cognitive power — the intellect. Psychology inquires into their modes of operation, their special features, and the general conditions of their growth and development. I'rom the higher power of cognition it proceeds to the study of spiritual appetency, rational desire, and free volition. The relations of will to knowledge, the qualities of conative activity, and the effects of re- peated volitions in the production of habit, con- stitute the chief subjects of investigation here. In connexion with these higher forms of cognition and desire, there will naturally be undertaken the study of conscience and the phenomena of the emotions.

Genetic Treatment a marked characleristic of Modern Empirical Psychology. — The constant aim of modern psychology is to analyse all complex mental opera- tions into their simplest elements and to trace oack to their first beginning all acquired or composite habits