PSYCHOLOGY (from Gk. :frux7), psycla7, breath, life, soul -Noy/a, -login, account, from Nlye/v, legein, to say). Psychology may be de fined as the science of mind. More exactly, it is the science of mind considered for the sake of mental facts and processes alone, and apart from their values or consequences. It is thus distin guished from the other mental sciences: from logic. which is concerned with the truth or error of reasoning processes; from epistemology, which is concerned with the validity of perception; from metaphysics, which deals with the consistency and reference of fundamental conceptions; and from ethics, which is concerned with ideas in relation to their influence upon conduct. Psychology is distinguished from all these, while at the same time it necessarily encroaches upon their terri tory in considering the mental facts with which they also deal. what distinguishes psychological science from the others being its point of view, which is primarily the observation and analysis of the immediate psychical phenomenon what: ever its nature.
The most important works which appeared be fore the advent of modern philosophy, works which the modern psychologist cannot afford to neglect, are Aristotle's treatise be _nniane with its appendices, the Parra Naturalia. and the ,Summa Theologies of the scholastic philosopher Thomas Aquinas. For Aristotle's psychology, consult the works of Wallace (Cambridge, 1882) and Hammond (London, 1901). Carus, Ge sehichte dcr Psyehologic (Leipzig. 1808), and Geschielrte der Psychologic (Berlin. 1878), have written general histories of psy chology, hut both are very incomplete. The two volumes of Siebeek, Geschichlc der Psyeholoyic (Gotha. 1880, 1884). extend only to Thomas Aquinas. Dessoir has recently published the first part of a Gesehichte der neueren deutsybm Psyrhologie (2d ed., Berlin, 1897).
The principal stages in the development of modern psychology may be characterized as the speculative or deductive. the empirical or assn eiationist. and the scientific or experimental. The first and third arc preponderantly German, the second English. The first may be said to culmi
nate in Hegel (consult Wallace. licgers Philoso phy of Jlind, Oxford, 1894), though it has con tinued in the 'purely introspective' works of the Berbartian school. The second contains the great names of English philosophy. from Thomas Hobbes down to John Stuart and Alexander Bain. The cardinal defect of this psychology is its confusion of the logical or epistemological standpoint with the standpoint of psychology proper. It conceives of perception. e.g. as a sum or aggregate of least bits of knowledge, which it terms sensations; and it is fond of appealing to the naïve consciousness for confirmation of its analysis. The associationist position has been largely transcended, though the epistemological reference still remains prominent, in the later English and American works of J. Ward, W. James, and G. F. Stout. In spite of all defi ciencies, the psychologies of the associationist school retain a high value on the level of de scriptive analysis. The third or experimental stage of psychology was inaugurated in Germany by the work of R. IL Lotze, Medizinischc Psy ehologie (Leipzig, 1852) : G. T. Fechner, Ele mente der Psychophysik (4. ltitiO) ; and W. M. Wundt, Grundzilge drr physiologischen Psychol ogie (ib., 1877). It should be added that France has made important contributions to modern psychology front the side of abnormal psychology ( Pierre Janet, II. Bernheim, Th. Ribot, A.
; and that the work of the English nine teenth-century writers upon ethnupsyehology (E. It. Tylor, J. Lubbock, It Spencer) can hardly be overestimated. The influences that determined the course of psychological thought in America were, down to about 1SSO, almost entirely theo logical and educational; and the principal works upon mental philosophy (N. Porter. J. Alc('osh) belong to the Scotch school of natural realism. In recent years .America has made very great advances in experimental psychology, in which she stands to-day second only to Germany. In the field of child psychology (G. S. Hall, J. M. Baldwin) America has left Germany (W. er) far behind.