Psychology

(Gr. psyche, logos; Lat. psychologia; Fr. psychologie; Ger. Seelenkunde)

In the most general sense, psychology is the science which treats of the soul

and its operations. During the past century, however, the term has come to be

frequently employed to denote the latter branch of knowledge — the science of

the phenomena of the mind, of the processes or states of human consciousness.

Moreover, the increasing differentiation, characteristic of the advance of all

departments of knowledge in recent years, has manifested itself in so marked a

manner in psychological investigation that there are already severe distinct fields

of psychological work, each putting forward claims to be recognized as a

separate science. The term psychologia seems to have first come into use about

the end of the sixteenth century (Goclenius, 1590, Casmann's "Psychologia

Anthropologica", 1594). But the popularization of the name dates from Ch. Wolff

in the eighteenth century.

History

Aristotle may well be deemed the founder of this as of so many other sciences,

though by him it is not distinguished from general biology, which is itself part of

physics, or the study of nature. His treatise peri psyches ("De Anima") was

during two thousand years virtually the universal textbook of psychology, and it

still well repays study. In the investigation of vital phenomena Aristotle employed

to some extent all the methods of modern science: observation, internal and

external; comparison; experiment; hypothesis; and induction; as well as

deduction and speculative reasoning. He defines the soul as the "Entelechy or

form of a natural body potentially possessing life". He distinguishes three kinds

of souls, or grades of life, the vegetative, the sensitive, and the intellectual or

rational. In man the higher virtually includes the lower. He investigates the several

functions of nutrition, appetency, locomotion, sensuous perception, and intellect

or reason. The last is confined to man. The working of the senses is discussed

by him in detail; and diligent anatomical and physiological study, as well as

careful introspective observation of our conscious processes, is manifested.

Knowledge starts from sensation, but sense only apprehends the concrete and

singular thing. It is the function of the intellect to abstract the universal essence.

There is a radical distinction between thought and sentiency. The intellect or

reason (nous) is separate from sense and immortal, though how precisely we are

to conceive this nous and its "separateness" is one of the most puzzling

problems in Aristotle's psychology. Indeed, the doctrines of free will and personal

immortality are not easily reconciled with parts of Aristotle's teaching.

Scholastic period

There is little effort at systematic treatment of psychology from Aristotle to the

medieval philosophers. For Epicurus, psychology was a branch of physics in

subordination to a theory of hedonistic ethics. With the introduction of

Christianity certain psychological problems such as the immortality and the

origin of the soul, free will and moral habits at once assumed a vastly increased

importance and raised the treatise "De Anima", to one of the most important

branches of philosophy. Moreover, the angels being assumed to be spirits in

many ways resembling the human soul conceived as separate from the human

body, a speculative theory of the nature, attributes, and operations of the angelic

beings, partly based on Scriptural texts, partly deduced by analogical reasoning

from human psychology, gradually grew up and received its final elaboration in

the Middle Ages in the metaphysical theology of the Schoolmen. The Christian

mystics were naturally led to consider the character of the soul's knowledge of

God. But their treatment of psychological questions is generally vague and

obscure, whilst their language indulges much in allegory and symbolism. Indeed,

the greatest of the mystics were not sympathetic with the employment of

Scholastic or scientific methods in the handling of mystic experience. The great

controversy between Realism and Nominalism from the early Middle Ages

directed much attention to the theory of knowledge and the problem of the origin

of ideas. However, although psychological observation was appealed to, the

epistemological discussions were largely metaphysical in character during this

period. To Albertus Magnus and St. Thomas the popularization of the psychology

of Aristotle throughout Europe during the thirteenth century was mainly due. In

Questions lxxv to xc of part I of the "Summa Theologica", St. Thomas gives a

very fairly complete and systematic account of the leading topics connected with

the soul. However, questions of biology, general metaphysics, and theology were

constantly interwoven with psychology for many centuries afterwards. Indeed, the

liberal use made of physiological evidence in psychological discussions is a

marked feature in the treatment of this branch of philosophy throughout the entire

history of scholastic philosophy. But although there is plenty of proof of acute

observation of mental activities, the usual appeal in discussion is rather to

metaphysical analysis and deductive argument than to systematic introspective

observation and induction, so characteristic of modern psychology. The treatise

"De Anima" of Suarez is a very good example of scholastic psychology at the

close of the Middle Ages. The treatise, containing six books, starts in book I with

an inquiry into the essence of the soul. Recalling Aristotle's definition of the soul

as the form of the body, the author proceeds to examine the relations of the

vegetative, sensitive, and rational soul. Next, in book II he treats of the faculties

of the soul in general and their relation to the soul as an essence. In book III he

investigates the nature and working of the cognitive faculties, and especially of

the senses. In book IV he inquires into the character of the activity of the

intellect. In book V he deals with faculties of appetency and free will. Book VI is

devoted to a speculative consideration of the condition and mode of operation of

the soul in a future life. In each question he begins with a summary of previous

opinions and then puts forward his own solution. The order of treatment starting

from the essence and passing thence to the faculties and their operations is

characteristic of the scholastic treatises generally. The method is mainly

deductive and the argument metaphysical, though in dealing with the senses

there is constant appeal to recognized physiological authorities from Aristotle to

Vesalius.

In psychology as well as in other branches of philosophy the influence of

Descartes was considerable though indirect. His subjective starting-point, cogito,

ergo sum, his insistence on methodic doubt, his advocacy of reflection on

thought and close scrutiny of our fundamental ideas, all tended to encourage the

method of internal observation, whilst the mechanical explanation of the "Traité

des Passions" favoured the advent of physiological psychology. It was probably,

however, John Locke's "Essay on the Human Understanding" (1690) which did

most to foster the method of analytic introspection which constitutes the

principal feature of modern psychological method. Notwithstanding the confused

and inconsistent metaphysics and the many grave psychological blunders with

which that work abounds, yet his frequent appeal to inner experience, his honest

efforts to describe mental processes, and the quantity of acute observations

scattered throughout the work, coming also at an age when the inductive method

was rapidly rising in popularity, achieved a speedy and wide success for his

book, and gave a marked empirical bent to all future English psychology.

Psychological observation and analysis were still more skilfully used by Bishop

Berkeley as a principle of explanation in his "Theory of Vision", and then

employed by him to establish his psychological creed of Idealism. Finally, David

Hume, the true founder of the Associationist school of psychology, still further

increased the importance of the method of introspective analysis by the daring

sceptical conclusions he claimed to establish by its means. The subsequent

British adherents of the Associationist school Hartley, the two Mills, Bain, and

Herbert Spencer, continued this method and tradition along the same lines.

There is constant direct appeal to inner experience combined with systematic

effort to trace the genesis of the highest, most spiritual, and most complex

mental conceptions back to elementary atomic states of sensuous

consciousness. Universal ideas, necessary truths, the ideas of self, time, space,

causality as well as the conviction of an external material world were all

explained as the outcome of sensations and association. The reality of any

higher activities or faculties essentially different from the lower sensuous powers

was denied, and all the chief data formerly employed in establishing the

simplicity, spirituality, and substantiality of the soul were rejected. Rational or

metaphysical psychology was thus virtually extinguished and erased from

English philosophical literature during the nineteenth century. Even the more

orthodox representatives of the Scotch school, Reid and Dugald Stewart, who

avoided all metaphysical argument and endeavoured to controvert Hume with his

own weapons of appeal exclusively to experience and observation, had only

further confirmed the tendency in the direction of a purely empirical psychology.

The great need in English psychological literature throughout most of the

nineteenth century, on the side of those defending a spiritual doctrine of the

human mind, was a systematic and thorough treatment of empirical psychology.

Excellent pieces of work on particular questions were done by Martineau, W. G.

Ward, and other writers, but nearly all the systematic treatises on psychology

were produced by the disciples of the Sensationist or Materialistic schools. Yet,

if philosophy is to be based on experience, then assuredly it is on the

carefully-scrutinized and well-established results of empirical psychology that

any satisfactory rational metaphysical doctrine respecting the nature of the soul,

its origin, and its destiny must be built. It was in their faulty though often

plausible analysis and interpretation of our states of consciousness that the

greatest errors in philosophy and psychology of Bain, the two Mills, Spencer,

and their disciples had their source; it is only by more careful introspective

observation and a more searching analysis of the same mental facts that these

errors can be exposed and solid foundations laid for a true metaphysical

psychology of the soul.

In France, Condillac, La Mettrie, Holbach, and Bonnet developed the

Sensationalism of Locke's psychology into an increasingly crude Materialism. To

oppose this school later on, Royer-Collard, Cousin, Jouffroy, and Maine de Biran

turned to the work of Reid and the "common sense" Scotch school, appropriating

their method and results in empirical psychology. Some of these writers,

moreover, sought to carry their reasoning beyond the mere inductions of

empirical psychology, in order to construct on this enlarged experience a

genuine philosophy of the soul, as "principle" and subject of the states and

activities immediately revealed to introspective observation.

In Germany the purely empirical tendency which had reduced psychology in

England to a mere positivistic science of mental facts did not meet with quite the

same success. Metaphysics and philosophy proper never fell there into the

degradation which they experienced in England in the beginning of the nineteenth

century. And although the old conception of a philosophical science of the nature

and attributes of the soul was rejected by Kant, and abandoned in the systems

of Fichte, Schelling, and Hegel, yet mere Phenomenalism was never completely

triumphant in Germany. Herbart, whilst denying the reality of faculties, postulates

a simple soul as the underlying subject of the presentations or ideas which form

our conscious life. Hermann Lotze, laying similar stress on the importance of

scientific observation of our mental states, insists even more strongly that our

introspective experience correctly interpreted affords abundant metaphysical

justification for the doctrine of an immaterial soul. Meanwhile the earlier attempts

of Herbart to express mental activities in mathematical formulæ led to a more

successful line of experimental research in the hands of Weber, Fechner, Wundt,

and others. The aim of this school is to attain the possible quantitative

measurement of conscious states. As this is ordinarily not directly possible,

much industry and ingenuity have been devoted to measuring quantitatively, by

the aid of skilfully devised instruments, the immediate physical antecedents and

effects of sundry mental activities, by which it is hoped to secure accurate

quantitative descriptions of the mental states themselves. Psychological

laboratories devoted to research of this kind have been set up in several

countries, especially in Germany and America. One of the most successful so

far is that at the Catholic University of Louvain, and another has lately been

established at that of Washington. In Great Britain, however, the special home of

empirical psychology since Locke, the new movement in favour of experimental

psychology has not, at all events down to the present time, met with much

success. The advance of physiological science, and especially of that of the

brain and nervous system, has also reacted on psychology, stimulating closer

inquiry into the relations between mental and bodily processes. It cannot,

however, be maintained that the progress of physiological knowledge,

considerable though it is, has brought us appreciably nearer to the solution of the

great problem, how body and mind act on each other. The study of nervous

pathology, of mental disease and of abnormal mental states, such as those of

hypnotism and double-consciousness, has also opened up new fields of

psychological research, constantly widening with the last thirty years.

Scope of Psychology

As we have already observed, recent writers commonly confine the term

psychology to the science of the phenomena of the mind. Thus William James,

probably the psychologist of widest influence during the past twenty years,

defines psychology as "The Science of Mental Life, both of its phenomena and

their conditions". ("Principles", I, 1). Wundt's definition is: "the science which

investigates the whole content of Experience in its relations to the Subject".

("Outlines", 3rd ed., 3). Other writers describe it as, "the science of the facts

apprehended by our internal sense", or again, "the science of our states of

consciousness, their laws of succession and concomitancy". The common

feature of all these definitions is the limitation of the scope of psychology to the

phenomena of the mind directly observable by introspection. In this view it is a

purely positivist science from which all philosophical problems are to be

excluded, as rigorously as from chemistry or geology. It is, in fact; la psychologie

sans âme. If such questions as the nature, origin, or destiny of the soul are to be

discussed at all, it must be, according to these writers, not in psychology, but in

some branch of speculation to be styled the metaphysics or ontology of the

human mind, and to be completely isolated from science.

In direct contrast with this view is that ordinarily adopted by Catholic writers

hitherto. By them, psychology has usually been conceived as one of the most

important branches of philosophy. In their view it may be best described as the

philosophical science, which investigates the nature, attributes, and activities of

the soul or mind of man. By soul, or mind, is understood the ultimate principle

within me by which I think, feel, will, and by which my body is animated. Whilst

the soul and the mind are conceived as fundamentally one, the latter term is

usually employed to designate the animating principle viewed as subject of my

conscious or mental operations; the former denotes it as the root of all vital

activities. By terming their branch of knowledge a philosophical science, it is

implied that psychology ought to include not only a doctrine of the laws of

succession and concomitance of our conscious states, but an inquiry into their

ultimate cause. Any adequate study of the human mind, it is contended,

naturally presents itself in two stages, empirical or phenomenal psychology, and

rational or metaphysical psychology. Though conveniently separated for didactic

treatment the two are organically connected. Our metaphysical conclusions as

to the nature of the soul must rest on the evidence supplied by our experience of

the character of its activities. On the other hand, any effort at thorough treatment

of our mental operations, and especially any attempt at explanation of the higher

forms or products of consciousness, it is urged, is quite impossible without the

adoption of some metaphysical theory as to the nature of the underlying subject

or agents of these states. Professor Dewey has justly observed: "The philosophic

implications embedded in the very heart of psychology are not got rid of when

they are kept out of sight. Some opinion regarding the nature of the mind and its

relations to reality will show itself on almost every page, and the fact that this

opinion is introduced without the conscious intention of the writer, may serve to

confuse both the author and his reader" ("Psychology", IV). Ladd, and others

also, recognize the evil of "clandestine" metaphysics when smuggled into what

claims to be purely "scientific" non-philosophical treatments of psychology.

Psychology is not in the same position as the physical sciences here. Whilst

investigating a question in geology, chemistry, or mechanics, we may, at least

temporarily, prescind from our metaphysical creed, but not so — judging from the

past history — when giving our psychological accounts and explanations of

mental products, such as universal concepts, the notions of moral obligation,

responsibility, personal identity, time, or the perception of an external material

world, or the simple judgment, two and two must make four. The view, therefore,

of those philosophers who maintain that the intrinsic connexions between many

of the questions of empirical and rational psychology are so indissoluble that

they cannot be divorced, seems to have solid justification. Of course we can call

the study of the phenomena of the mind, "Psychology", and that of its inner

nature, the "Philosophy of the Mind"; and we may treat each in a separate

volume. That is merely a matter of terminology and convenience. But the

important point is that in the explanatory treatment of the higher intellectual and

rational processes, it will practically be impossible for the psychologist to

preserve a philosophically neutral attitude. A truly scientific psychology,

therefore, should comprise:

(1) a thorough investigation by introspective observation and analysis of

our various mental activities — cognitive and appetitive, sensuous and

rational — seeking to resolve all products of the mind back 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 Psychology

The primary 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 from other quarters has finally to be interpreted in terms of our own

subjective experience. 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 in 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 absence of particular senses,

and in abnormal or pathological conditions such as dreams, hypnotism, and

forms of insanity. Moreover, the anatomy, physiology, and pathology of the brain

and nervous system supply valuable data as to the organic conditions of

conscious states. Experimental psychology, psychophysics, and psychometry

help towards accuracy 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 sources of information 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

universal character of the observations on which the physical sciences are built.

Introspection is frequently spoken of as the subjective method, these other

sources of information as supplementary objective 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

psychology, or even sciences in their own right. Thus we have comparative

psychology including animal psychology, child psychology, and race

psychology. 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 approached 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 "New Psychology" 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 faculty's response to

stimulation. Certain properties of memory have also been made the subject of

measuring experiments and more recently considerable industry has been

devoted, especially by Külpe and the Würzburg 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 experimental psychology. Whilst Wundt, the leader of the new

movement for the past fifty years, places the only hope of psychological progress

in the experimental method, William James's judgment on the entire literature of

the subject since Fechner (1840) was that "its proper psychological outcome is

just nothing at all" ("Principles", I, 534). Apart, however from the very modest

positive results, especially in the higher forms of mental life, which the

experimental method has achieved or may achieve in the future, its exercise may

nevertheless prove a valuable agency in the training of the psychological

specialist, both in increasing his appreciation of the value of the most minute

accuracy in descriptions of mental states, and also by fostering in him habits of

precision and skill in systematic introspection.

Classification

The Faculties

In empirical psychology, with modern writers, 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 bipartite division of faculties into

those of cognition and appetency. The former they subdivided into sensuous, and

intellectual or rational. The sensuous faculties they again subdivided into the five

external senses and the internal activities of imagination, sensuous memory,

sensus communis, and vis cogitativa. But there was much disagreement as to

the number, character, and boundary lines of these internal forms of sensuous

cognition. There were also divergences of opinion as to the nature of the faculties

in general in themselves and to what extent there was a distinctio realis between

faculties and the essence of the soul. But, on the other hand, there was general

agreement as to an essential difference 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 psychologist naturally begins with the treatment of the phenomena of

sentiency. The several senses, their organic structure and functions, the various

forms of sentient activity with their cognitive, hedonic and appetitive properties

and their special characteristics have to be carefully analyzed, compared, and

described. Next, imagination and memory 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. Intellect follows. The consideration of this faculty

includes the study of the processes of conception, judgment, reasoning, rational

attention, and selfconscious reflection. These, however, are all merely different

functions of the same spiritual cognitive power — the intellect. Psychology

inquires into their modes of operation, their special features, and the general

conditions of their growth and development. From 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

repeated volitions in the production of habit, constitute 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 characteristic of Modern Empirical Psychology

The constant aim of modern psychology is to analyse all complex mental

operations into their simplest elements and to trace back to their first beginning

all acquired or composite habits and faculties, and to show how they have been

generated or could have been generated from the fewest original aptitudes or

fundamental activities of the mind. This is sound scientific procedure —

recognized in the Scholastic aphorism, Entia non sunt multiplicanda prœter

necessitatem. We may not postulate a special faculty for any mental state which

can be accounted for by the co-operation of already recognized activities of the

soul. But the labour and skill devoted during the past century and a half to this

combined analytic and synthetic procedure has developed one feature of modern

psychology by which it is differentiated in a most marked manner from that of the

Middle Ages and of Aristotle. The present-day treatment is pronouncedly genetic.

Thus, whilst the Schoolmen in their account of mental operations, such as

perception, conception, or desire, considered these processes almost solely as

elicited by the normal adult human being already in full possession and control of

matured mental powers, the chief interest of the modern psychologist is to trace

the growth of these powers from their first and simplest manifestations in infancy,

and to discriminate what is the product of experience and acquired habits from

that which is the immediate outcome of the innate capabilities of the soul. This is

particularly noticeable if we compare the treatment of the mental operation of

perception as given in most Scholastic textbooks with that to be found in any

modern handbook of psychology. The point of view is usually quite different.

Since much of the most plausible modern attacks on Scholastic psychological

doctrine has been made in this manner, the genetic treatment from the Thomist

standpoint of many psychological questions seems to us to be among the most

urgent tasks imposed nowadays on the neo-Scholastic psychologist. The value

of such work from a philosophical standpoint would seem to be distinctly greater

than that of any results likely to be achieved in quantitative experimental

psychology. Obviously there is nothing in the Thomistic conception of the soul

and its operations incompatible with a diligent investigation into the unfolding of

its various aptitudes and powers.

Rational Psychology

From the study of the character of the activities of the mind in experimental

psychology, the student now passes on to inquire into the nature of the principle

from which they proceed. This constitutes the more philosophical or

metaphysical division of the science. For, as we have indicated, the analysis and

explanatory accounts of the higher forms and products of mental activity, which

the scientific psychologist is compelled to undertake even in phenomenal

psychology, involve metaphysical assumption and conclusions which he cannot

escape — certainly not by merely ignoring them. Still, it is in this second stage

that he will formally evolve the logical consequences to which his previous study

of the several forms of mental activity lead up. His method here will be both

inductive and deductive; both analytic and synthetic. He argues from effect to

cause. From the character of the mental activities already scrutinized with so

much care, he now concludes as to the nature of the subject to which they

belong. From what the mind does, he seeks to learn what it is. In particular, from

the simple spiritual nature of the higher activities of intellect and will, he infers

that the being, the ultimate principle from which they proceed, must be of a

simple and spiritual nature. Consequently, it cannot be the brain or any corporeal

substance. Having established the simplicity and spirituality of the soul, he then

goes on to deduce further conclusions as to its origin, the nature of its union with

the body, and its future destiny. In this way by rational arguments the Scholastic

thinkers claim to prove that the human soul can only have arisen by creation,

that it is naturally incorruptible, and that the boundless aspirations of the

intellect, the insatiable yearnings of the will, and the deepest convictions of the

moral reason all combine to establish a future life of the soul after death.

Important special questions of psychology are treated under the articles ANIMISM; ASSOCIATION

OF IDEAS; CONSCIOUSNESS; ENERGY; FACULTIES OF THE SOUL; FORM; FREE WILL; IDEA;

IMAGINATION; IMMORTALITY; INDIVIDUAL, INDIVIDUALITY; INTELLECT; LIFE; PERSONALITY.

General Psychology: among the Scholastic Latin manuals there is much uniformity of treatment.

URRÁBURA, Psychologia, I, II (Rome and Paris, 1894), is exhaustive. HICKEY, Psychologia (2nd

ed., Dublin and New York, 1910) is an easy useful introduction; BOEDDER, Psychologia Rationalis

(4th ed., Freiburg and New York, 1903). English: MAHER, Psychology, Empirical and Rational (7th

ed., New York and London, 1911). French: MERCIER, Psychologie (4th ed., Louvain, 1903);

GARDAIR, Philosophie de St Thomas (Paris, 1892-95); FARGES, Etudes Philosophiques, I-VI

(Paris, 1890-95). German: GUTBERLET, Die Psychologie (Münster, 1896). English works of various

schools: LADD, Psychology, Descriptive and Explanatory (New York and London, 1895); IDEM,

Philosophy of Mind (New York and London, 1895); JAMES, Principles of Psychology (New York and

London, 1890); STOUT, Analytical Psychology (London and New York, 1902); SPENCER,

Principles of Psychology (New York and London, 1904); BAIN, Senses and Intellect; IDEM,

Emotions and Will (London, 1894). Physiological: LADD, Elements of Physiological Psychology

(New York and London, 1894); WUNDT, Principles of Physiological Psychology (tr., New York and

London, 1904). Experimental: TITCHENER, Experimental Psychology, parts I, II (4 vols., New York

and London, 1901-05); KÜLPE, Outlines of Psychology (tr. New York and London, 1894);

MEUMAN, Vorlesungen, Experimentelle Pädagogik (Leipzig, 1907). Comparative: WASMANN,

Instinct and Intelligence (tr. New York and London, 1903); IDEM, Psychology of Ants and Animals

(1905); MIVART, Origin of Human Reason (London, 1889). Child Psychology: TRACY, Psychology

of Childhood (Boston, 1907); PREYER, The Mind of the Child, vol. I-II (tr. New York and London,

1901); PEREZ, First Three Years of Childhood (tr. New York and London, 1892);

MARENHOLZ-BULON, Child and Child Nature (tr. London, 1904); SULLY, Children's Ways (London,

1898); BURKE, Child Study (Dublin, 1908). History: general histories of philosophy, such as

TURNER, History of Philosophy (Boston and London, 1903); DE WULF, History of Philosophy (tr.

London and New York, 1909); STÖCKL, History of Philosophy (tr. New York and Dublin, 1887);

PERRIER, Revival of Scholastic Philosophy in the Nineteenth Century (New York, 1909), contains

also a useful bibliography of neo-Scholastic philosophy; SIEBECK, Gesch. der Psychol. (1904). See

also: BALDWIN, Dictionary of Philosophy and Psychology; and EISLER, Wörterbuch (Berlin, 1904).

Michael Maher

Transcribed by Douglas J. Potter

Dedicated to the Sacred Heart of Jesus Christ

The Catholic Encyclopedia, Volume XII

Nihil Obstat, June 1, 1911. Remy Lafort, S.T.D., Censor

Imprimatur. +John Cardinal Farley, Archbishop of New York

The Catholic Encyclopedia: NewAdvent.org