Classics in the History of Psychology

An internet resource developed by
Christopher D. Green
York University, Toronto, Ontario
ISSN 1492-3173

(Return to Classics index)



Definitions Der - Dn

Posted June 2000

Derangement [Fr. de + ranger, to put in order]: Ger. Geistesstörung; Fr. dérangement d'esprit; Ital. disordine. As applied to mental conditions, the term indicates any form of insanity, or divergence from normal soundness of reason. The mind, or the person, is said to be deranged when a distinct form of insanity, or an irresponsible condition, is present. See SANITY AND INSANITY. (J.J.)

Derivation (linguistic) [Lat. derivatio?]: Ger. Ableitung, Derivation; Fr. dérivation; Ital. derivazione. The history of a word in terms of its formation from a shorter basal element or word called the root. Words formed from other words or from roots by the addition of suffixes are called derivatives.

Thus friendliness is said to be derived from friend; friend itself from the root frij, 'to love'; holy from whole, &c. But such statements, while serving an immediate practical purpose, by misrepresenting the historical facts usually lack scientific exactness. See ETYMOLOGY. (B.I.W.)

Dermal Sensation [Gr. derma, the skin]: Ger. Hautempfindung; Fr. sensation de la peau, sensation cutanée; Ital. sensazione cutanea. A synonym (used, e.g., by Sanford, Course in Exper. Psychol., chap. i) for CUTANEOUS SENSATION (q.v.). (E.B.T.)

Descartes (or Des Cartes), René. (1596-1650.) A French philosopher and mathematician, born at La Haye, who entered upon his education at the college of La Flèche. In 1612 he left school, dissatisfied with scholastic methods and doctrines. In 1616 he joined the Dutch army; in 1619 that of the duke of Bavaria. In 1621 he renounced his military profession, and began again the pursuit of knowledge, travelling in Italy, France, and other countries. In 1629 he settled in Holland. In 1647 the French court granted him a pension. Invited to the Swedish court by Queen Christina, he went to Stockholm, where he died. He is properly called the 'father of modern philosophy.' See MIND AND BODY, OCCASIONALISM, and PRE-ESTABLISHED HARMONY.

Descent (doctrine of): Ger. Abstammungslehre, Descendenzlehre; Fr. théorie de la descendance; Ital. teoria della discendenza (or dell' evoluzione). The theory that all the diverse forms of organic life are the descendants, through the ordinary processes of reproduction, of previously existing forms. Descent of man is the origin of man in accordance with this theory. (E.S.G.- J.M.B.)

This theory, that animals and plants are in all cases genetically related to earlier forms, is the doctrine of continuity in evolution as applied to the organic world. Its general acceptance among biologists may be said to be due to the publication of the Origin of Species. Darwin used the phrase 'descent with modifications' to characterize the theory of evolution. It should be noted, however, that the term MODIFICATION (q.v.) has since been used by some authors with a specialized meaning.

Literature: C. DARWIN, Origin of Species; E. HAECKEL, History of Creation; O. SCHMIDT, Doctrine of Descent. See the literature of EVOLUTION. For the influence of the theory of descent upon classification see E. R. LANKESTER, art. Zoology in Encyc. Brit. (9th ed.), xxiv. (C.LL.M.- J.M.B.)

Descent (in logic): see QUANTITY (logical).

Description [Lat. de + scribere, to write]: Ger. Beschreibung; Fr. description; Ital. descrizione. The statement of the distinctive marks of an object, the marks being of such a kind as can be presented in direct perspective experience.

Descriptions, accordingly, may be more or less complete, according as the purpose, the distinction of the object, may be effected by more or less enumeration of detail. It is an accepted doctrine of logic that the concrete individual object can be described, not defined. Empirical theory of knowledge tends to regard detailed, complete description as identical with explanation. See SCIENCE, and cf. APPRECIATION. (R.A.)

Desert [Lat. de + servire, to serve]: Ger. Verdienst; Fr. mérite; Ital. merito. What is due to a man in the way of praise or reward, blame or penalty, in respect of the usual quality of his conduct.

From the moral point of view, a man's desert depends on his personal attitude to morality, and not merely on the social utility of his achievements. See MERIT. (W.R.S.)

Design (in philosophy) [Lat. designare, to mark out]: Ger. Zweck; Fr. dessein; Ital. disegno. The attribution of cases of adaptation in nature to conscious design.

A form of TELEOLOGY (q.v.), in which the concept of finality is anthropomorphic and is carried into the details of nature. It is the ground for the argument from design for the existence of God. It is characteristic of the more deistic forms of THEISM (q.v.). (J.M.B.)

Design (in psychology): Ger. Ziel (Absicht); Fr. dessein; Ital. disegno. A conscious and deliberate plan of action. Cf. PROJECT, PLAN, INTENTION, and PURPOSE.

A design is an END (q.v.) which is more or less remote, and for whose attainment the means are more or less clearly understood and within control. It carries the idea also of some preliminary deliberation. We will to move a limb, or to taste of a dish, but we design to take a walk, or to eat a dinner. This is the tendency of usage, but it might be more consistent than it is. (J.M.B., G.F.S.)

Designate and Designation: see TERM (logical).

Desire [Lat. desiderare, to wish for]: Ger. Begehrung, Begehren (abstract); Fr. désir; Ital. desiderio. Appetence, in which the attainment of an end is represented by means of a train of ideas.

Our definition restricts the application of the term to a special form of conation or appetence, arising only at a certain level of mental development. This usage is modern. The earlier psychologists, such as Wolf and Locke, apply the word to the conative side of our nature in general. But it does not appear that the connotation which they attached to the word differs essentially from that which we have assigned to it. They made it coexistent with conation in general, only because they failed to distinguish more primitive and simple from more developed and complex modes of the conative attitude. 'The cases in which the subject is incited to action by ideas, as distinct from perceptions, are cases of desire. . . . By the time that ideas are sufficiently self-sustaining, they form trains that are not wholly shaped by the circumstances of the present; entirely new possibilities of action are opened up. We can desire to live again through experiences of which there is nothing actually present to remind us; and we can desire a new experience which as yet we only imagine' (Ward, as cited below, 73-4).

Literature: WARD, art. Psychology, Encyc. Brit., Pt. XX; GREEN, Prolegomena to Ethics, Bk. II. chap. ii; BALDWIN, Handb. of Psychol., Feeling and Will, 320-30; LADD, Psychol., Descrip. and Explan., 601-8; SIDGWICK, Meth. of Eth., Bk. I. chap. iv; HÖFFDING, Psychologie, 325; JODL, Lehrb. d. Psychol., 426. For desire, in the general sense of conation, see CONATION; also the citations made by EISLER, Wörterb. d. philos. Begriffe, 'Begehren.' (G.F.S., J.M.B.)

Despair: see HOPE AND DESPAIR.

Despotism [Gr. despothV, master, lord]: Ger. Despotismus; Fr. despotisme; Ital. despotismo. (1) As a form of government, despotism is the sovereign and arbitrary rule of a single person. (2) It is frequently applied to arbitrary rule, even of a subordinate ruler.

Despot is in Greek originally the master of a slave, and is very properly applied by Herodotus to the Persian kings. To Aristotle (Pol., III. ix; Ethics, VIII. x) despotic government (nearly convertible with tyrannical) is that of a single ruler that rules, not for the public good, but for his own. In our own time we should feel that despotism would be a less harsh term than tyranny to apply to a rule like that of the czar of Russia, which, though arbitrary, is not without laws, nor entirely for the ruler's personal advantage. The use of "despot," in the later Byzantine empire (see Murray's Eng. Dict., and Gibbon, Decline and Fall, chap. liii), for the first of the princes of the blood under the emperor, was of course not warranted, either by derivation or history. See AUTOCRACY, and ABSOLUTISM. (J.B.)


Destutt, Antoine Louis Claude, Comte de Tracy. (1754-1836.) Born of an ancient and noble family of France, he joined the army, and, after brilliant service, the party of the Revolution. He sat in the Constitutional Assembly beside Lafayette, and during the Reign of Terror was imprisoned. Two days before his trial the Reign of Terror ended, and he was released. It was during his imprisonment that he conceived the plan of his greatest work. During the Consulate the Society of Ideologists met at his house in Auteuil near Paris, among them Dabains and Benjamin Constant. He has been called the logician and metaphysician of the school of Condillac.

Desuetude (in law) [Lat. desuetudo]: Ger. Abkommen, ausser Gebrauch treten; Fr. désuétude; Ital. disuso. Discontinuance of use; especially of the use of some part of the unwritten law.

The term correlative with custom (consuetudo). What law custom creates, disuse may eventually abrogate (Effinger v. Lewis, 32 Pennsylvania State Reports, 367). 'Rectissime etiam illud receptum est ut leges non solum suffragio legislatoris, sed etiam tacito consensu omnium per desuetudinem abrogentur' (Dig., i. 3, De Legibus, &c., 32, § 1).

By the law of England and the United States, no legislative enactment is abrogated by desuetude. Statutes may be treated as 'dead letters' by the public, but never are by the courts, except as juries in criminal cases may virtually disregard them, by acquitting a person charged with their violation, not because the act was not proved, but because they consider them as obsolete, and so of no force. (S.E.B.)

Determinants [Lat. determinare, to limit]: Ger. Determinanten; Fr. déterminants; Ital. determinanti. The hypothetical group of hypothetical units or biophores, by the distribution of which during development the differentiations of the multicellular organism are determined.

The determinant takes its place in the elaborate scheme of heredity developed by Weismann. Admittedly hypothetical, it none the less serves to make clear a definite conception. See A. Weismann, The Germ Plasm (1893). (C.LL.M.)

Determinate (in biology) [Lat. determinatus, from determinare, to limit]: Ger. bestimmt, bestimmt gerichtet; Fr. déterminé, (variation) orientée (Y.D.); Ital. determinato. (1) Congenital variations in definite directions, due to some specific cause, and not conforming to the law of probability, are said to be determinate, as contrasted with indeterminate, indefinite, or fortuitous. (C.LL.M.- J.M.B.)

(2) Evolution resulting from the continued action of some cause by which its course is directed is said to be determinate. See ORTHOGENESIS, and ORTHOPLASY, (J.M.B.- C.L.L.M.)

(1) According to some biologists, individual modifications of structure, due to use or the action of the environment, in one generation, determine congenital variations of a similar kind in the next generation. According to others, the survival, under natural selection, and interbreeding of those which vary congenitally in certain directions produces further variability in these directions, simply by shifting the mean, and evolution becomes determinate (sense 2), although variations are really not so. According to still others, variations are determined by an inner tendency, at present unexplained by science.

(2) According to some, for whom determinate variations do not exist, the course of evolution is determined solely by the action of the environment, direct or indirect (extrinsic determination, extreme Neo-Darwinism); according to others, it is mainly determined by the inherent nature of organic life, producing determinate variations (intrinsic determination, Neo-Lamarckism, orthogenesis); and according to still others, it is due to the supplementing of natural selection by the screening influence of individual accommodations upon indeterminate variations (organic selection, orthoplasy). See MODIFICATION, VARIATION, and ACQUIRED CHARACTERS. (C.LL.M.- J.M.B.)

Determination (logical) [Lat. determinatio]: Ger. Determination, Bestimmung; Fr. détermination; Ital. determinazione. The form of definition which restricts the generality of a notion by adding marks to its meaning, that is, by increasing its comprehension or depth.

So the prosqesiV of Aristotle (Anal. Post., i. 27, 87 a). Spinoza (Epist. 59) made a metaphysical application in denying all determination to the absolute, since omnis determinatio est negatio, the denial of the contrary of the marks which are added. Similarly Schelling. Among modern logicians, determination has come to mean the process of restricting the generality by definition (Ueberweg, Logik, 4th ed., § 52). See additional citations in Eisler, Wörterb. d. philos. Begriffe, sub verbo. (R.A.)

Determination (psychical or mental). The co-operation of all the factors which adequately condition and issue in a mental END-STATE (q.v.). See also END (meaning 2).

The essential matters are progress towards an end-state, generally involving a series of changes, and the inclusion of no elements extraneous to the state whose determination is in question. The conception of determination in the individual mind is analogous to that of psychological and biological determination in evolution. Cf. the other forms of DETERMINATION. (J.M.B., G.F.S.)

The distinctive use of 'psychical' or 'mental' (in contrast with 'psychological' DETERMINATION; see next topic) should be noted. The former indicates the individual's own consciousness of a process, the latter the observation of a process by another observer. This general contrast of points of view is recommended under PSYCHICAL AND PSYCHOLOGICAL. (J.M.B.- G.F.S.)

The subject has been discussed under various terms, the principal question being as to the relative share of subjective factors, such as associations, dispositions, &c., on the one hand, and objective, nervous or stimulating factors on the other hand, in the several typical modes of mental determination, especially those of mental objects, and of volitions. The adaptive determination of thought progressively has been called, by Stout, RELATIVE SUGGESTION (q.v.); and the theory that volition is always a case of determination, in the sense of the definition, has been called DETERMINISM (q.v.), as opposed to INDETERMINISM (q.v.). The present writer has applied the phrase systematic determination to the series of progressive determinations -- each from the platform of the earlier system -- which make up the development of knowledge as a whole. An interesting case is indicated by the phrase 'decision or determination to act' thus, or so; it is really a predetermination of an end for action, being an end-state resulting from the earlier determination known as deliberation.

Literature: STOUT, Analytic Psychol.; SIMMEL, Arch. f. syst. Philos., i; URBAN, Psychol. Rev., July, 1892; BALDWIN, Social and Eth. Interpret., §§ 55-7, 78, and in Psychol. Rev., Jan., 1898. (J.M.B.)

Determination (psychological). The evolution of mind considered as showing a series of forms progressively determined towards greater complexity. It is correlative to the biological determination seen in 'determinate evolution,' and analogous -- as a problem -- to the mental or psychic determination of the individual's 'stream of thought.'

Literature: see titles under DETERMINATION (mental). Also JAMES, Princ. of Psychol., ii, ad fin. (J.M.B.)

Determinism [Lat. de + terminus, end]: Ger. Determinismus; Fr. déterminisme; Ital. determinismo. The theory according to which choice between alternative courses of conduct can, in all cases, be fully accounted for by psychological and other conditions. See FREE WILL CONTROVERSIES, and DETERMINATION (mental). (G.F.S.- J.M.B.)

Determinism (in biology). The doctrine that all organic phenomena have efficient causes or antecedents, in terms of which they are explicable.

Biological determinism asserts that, no matter what psychological phenomena may or may not accompany organic changes, these changes in themselves are determined by antecedent vital changes. See EVOLUTION (cosmic). (C.LL.M.- J.M.B.)

Determinism (theological): see FORE-ORDINATION.

Deus ex Machina [Lat.]. Divine agency considered as apart from nature, and modifying or interfering with it on occasion.

This view was developed in its philosophical form in what is known as DEISM (q.v.). The expression is often used as setting into relief an artificial and extreme dualistic vein in theistic discussion. (J.M.B.)

Deuteranopia [Gr. denteroV, second, + a + oyomai, to see]: Ger. Deuteranopie; Fr. and Ital. not in use. The name proposed by v. Kries for what was formerly called green-blindness. See PROTANOPIA. (C.L.F.)

Deutoplasm [Gr. denteroV, second, + plasma, substance]: Ger. Nahrungsdotter; Fr. deutoplasme, lécithe; Ital. deutoplasma. That portion of the egg which affords nourishment to the formative protoplasm; commonly called the yolk. Proposed by Van Beneden (1870). (C.LL.M.)

Development (biological) [Lat. devolutus, through the Fr.]: Ger. Entwicklung; Fr. développement; Ital. sviluppo. The entire series of vital changes normal to the individual organism, from its origin from the parent cell or cells until death.

Development refers to the individual (ONTOGENESIS), evolution to the race (PHYLOGENESIS), a distinction of terms (q.v.) made by Haeckel. In most organisms there are well-marked stages in development, characterized by structural changes. For the law of such changes during the prenatal or embryological period see RECAPITULATION; on changes in the subsequent periods see DEVELOPMENTAL INSANITIES, ADOLESCENCE, SENESCENCE. Cope and Hyatt have formulated a law of decay, according to which the individual's retrograde development, or decline after maturity, anticipates the future degeneration of the species to which it belongs, giving a sort of reverse recapitulation.

For the distinction between development and growth see GROWTH, and GROWTH (psychic); if made in biology, it would mean that development applies to what is constitutional and characteristic of the species, growth to what is acquired by the individual -- development to adaptation, growth to ACCOMMODATION (q.v.). In addition to the topics referred to, see EMBRYOLOGY.

Literature: see topics mentioned above; HYATT, Science, N.S., Jan. 27, 1897; HAECKEL, Gen. Morphol. (1866). (J.M.B.-E.B.P.)

Development (mental): see MENTAL DEVELOPMENT, and EVOLUTION (mental).

Development Formula: see SYMBOLIC LOGIC.

Developmental Insanities: Ger. Entwicklungspsychosen; Fr. psychoses du développement; Ital. psicosi dello sviluppo (e.g. della pubertà). Those nervous disorders which tend to appear at certain periods in the growth and development of the brain.

The bringing to complete fruitage of the highest evolution in nature is a most delicate process, subject to dangers of many kinds, and incident to different periods. While these may be aggravated by unhygienic conditions, the determining factor is heredity. 'A bad or a good heredity means more during development than after.' Most of the disorders of development are accordingly regarded as manifestations of nervous instability, or of a neurotic diathesis. Such taint may be so slight that, under ordinary circumstances, the individual would pass through his normal span of years without mental disorder or marked abnormality; but under the influence of misfortune or excitement, particularly if it occur at critical periods in his life, he is apt to exhibit pathological symptoms. Those bearing upon them the marks or stigmata of DEGENERATION (q.v.) are specially prone to developmental neuroses.

Developmental disorders in children are apt to take the form of convulsions, delirium, night-terrors, somnambulism, and the like. During dentition, convulsion is the typical form of manifestation of an unstable brain. The delirium may be connected with a distinct fever, but the high temperature does not of itself lead to delirium except in the predisposed brain.

The developmental neuroses incident to puberty and adolescence are of supreme importance; for these periods are recognized as the ones when breakdown is most imminent, when the tyranny of heredity is most apt to make itself felt, when the decadence of the unfit begins to appear. Epilepsy and, especially, hysteria are apt to appear in the years following puberty.

The ages from twenty to twenty-five are most liable to mania and neurasthenia; and the percentage of cases of insanity which occur at this period, in which hereditary influences can be traced, is unusually large. Many of the forms of mental disturbance incident to this period, while not technically insanities, are yet significant. A characteristic form of minor psychosis may appear as an exaggerated self-will: the youth or maiden becomes ungovernable, breaks out into attacks of violence, becomes lazy, may be prone to deceit and lying, may leave home without reason, or create scandal. In all this there is a characteristic periodicity, periods of abandonment and excess giving way to propriety and self-restraint. It would be misleading to regard such attacks as insanity, but they are closely related causally to the influences which produce true insanity. The form of insanity usually described as the insanity of adolescence is characterized by a maniacal tendency (seventy-eight per cent.) and a motor restlessness. 'The mania is, in the male sex, restless, boisterous, full of mock-heroic pseudo-manliness, obtrusive pugnaciousness, with often a morbid sentimentality; while in the female sex we find also restlessness, with lack of self-control, intolerance of control by others, impulsiveness, hysterical obtrusiveness, and emotional perversion. In both sexes we naturally find strong and perverted sexual ideas and practices.' Periodicity of attack and remission is particularly characteristic, and is related, in women especially to the periodicity of sexual functions. In about one-third of all cases the ending is secondary dementia -- a severe decay of mental functions, comparable to extreme idiocy. Such dementia, however, may be consistent in some cases with the spasmodic, but transitory, display of latent mental powers. Some cases recover once or twice with years of sanity, but in the end pass into true dementia. Less frequently the adolescent insanity is of a melancholic type, still showing remissions, but not so definitely as in maniacal cases; there is apt to be hypochondria and extreme concentration upon one's self. Suicidal tendencies may occur; religious depression and delusions are frequent. Such cases when persistent develop into forms of stupor -- more common in females than in males. Masturbation in males, and hysterical symptoms in females, are the chief complications.

Akin to adolescent insanities are those connected with childbirth, with the climacteric, and with senility. All these relate to periods of development in the progress from birth to death, and are dominated by hereditary influences and endowments. For description of these in relation to development see Clouston, Ment. Diseases.

A different view of this subject is taken by Kraepelin, who recognizes the occurrence of several distinct disease-processes of characteristic course and outcome. See PSYCHOSIS.

Literature: T. S. CLOUSTON, Ment. Diseases (4th ed., 1883); The Neuroses of Development (1891); and Developmental Insanities, in Tuke's Dict. of Psychol. Med.; EMMINGHAUS, Die psychol. Störungen des Kindesalters (1887); J. LANGDON DOWN, Mental Affections of Childhood (1889); MARRO, La Pubertà (1896-8); KAHLBAUM, Die Hebephrenie; SACHS, Nervous Diseases of Children (1895); MORGAN, Der Irrsinn im Kindesalter (1889); ZIEHEN, MARRO, and VOISIN, Proc. XIII internat. Med. Cong., 1900. See also under ADOLESCENCE. (J.J.)

Developmental Mechanics: Ger. Entwicklungsmechanik; Fr. bioméchanique (Delage; see, however, Roux, as below, viii. 362); Ital. (not in use). The department of biology which investigates by experimental methods the development of the individual organism, conceived as consisting in more or less mechanical reaction to the stimulating conditions of the environment.

The term was suggested and the department of research was much furthered by Roux, who founded the Archiv f. Entwicklungsmechanik. Cf. BIOLOGICAL SCIENCES. (J.M.B.)

Deviation [Lat. deviare, deviate]: Ger. Ablenkung, Deviation; Fr. déviation; Ital. deviazione. In general, a turning from, as the deviation of a ray of light in passing through a prism, or the turning aside of the eye from a given position.

An abnormal and somewhat persistent turning of the eyes (and head) to one side is termed conjugate deviation, and may result from a lesion in one hemisphere. Such conjugate deviation is thus a symptom of hemiplegia; the (head and) eyes cannot be turned towards the affected side, or the unopposed antagonistic muscles may turn the eyes towards the unparalyzed side.

Besides conjugate deviation, primary and secondary deviation are distinguished. If the lateral muscle of one eye be paralyzed, then the deviation of the axis of the paralyzed eye is the primary deviation. Such deviation may be convergent or divergent, according as the external or internal rectus is affected. If the patient is required to fixate an object with his affected eye, while the sound eye is prevented from seeing the object, the sound eye will move still further in one direction, and the deviation of the visual axes is increased: this increased deviation is the secondary deviation. These results follow from the innervation mechanism of binocular vision (see also VISION, defects of). Deviation may produce double vision or DIPLOPIA (q.v.). Cf. Norris and Oliver, System of Diseases of the Eye, iv. (J.J.)

Deviation of the Retinal Meridians: Ger. scheinbare verticale Meridiane der Sehfelder; Fr. déviation des méridiens verticaux apparents; Ital. deviazione dei meridiani, ecc. The name given to a slight normal irregularity in the arrangement of CORRESPONDING POINTS (q.v.), most evident in the case of the apparent retinal vertical.

Literature: VOLKMANN, Physiol. Untersuchungen im Gebiete d. Optik (1864); SANFORD, Course in Exper. Psychol., expt. 209; used in explanation of certain optical illusions by ZEHENDER, Zeitsch. f. Psychol., xx. 65 (1899). (E.B.T.)

Devil [Gr. o diaboloV, the slanderer]: Ger. Teufel; Fr. diable; Ital. diavolo. In the language of religion, the name given to an apostate angel, who is the instigator of evil, and the 'ruler of the kingdom of darkness.' The term diabolism is applied to actions which are devilish, as those attributed to the victims of demon possession. See DEMONOMANIA. (R.M.W.- J.M.B.)

This conception, which gradually became personified in Christian theology, can be traced in the earliest and rudest religious conceptions of man, and probably had source in the double nature of humanity. The contrast between body and spirit, between self and not-self, is responsible for the growth of the contrasted feelings of a will to do and an opposing power. In the lowest nature-religions, where there are no moralized deities, we find conceptions of destructive demons who must be propitiated. Mischief, rather than evil, is originated by such beings. Higher in the scale, we come upon such 'adversaries' as Typhon, the Titans, Ahriman, Moloch, Siva. And, sometimes, as in the case of the Phoebus Apollo, the same divinity is worshipped under two aspects -- as the patron of good, and as the author of vengeance. All this lies within the realm of myth; that is to say, it belongs to the pictoral representation of certain broad facts in human experience. With the rise of apocalyptic ideas, in the first century, the Jewish conception of Satan began to be personalized; this process was completed, thanks to the intervention of the later Greek conceptions of angels and demons, and to the direction taken by the Christian consciousness during the years of the formation of the Church. By the 6th century the personification is so complete that the devil is able to appear disguised as Christ, and to employ this ruse for the destruction of souls. Its persistence and domination is attested by the prosecutions for witchcraft, which continued till near the close of the 18th century, and attained their height in the 17th.

It is noticeable, from the philosophical standpoint, that theology has always treated the devil from a psychological or ethical standpoint. The problem involved is really ontological, and as a consequence of philosophical criticism, coupled with the modern explanation of the myth by way of historical development, the idea is now without vital influence. The whole matter belongs to the sphere of metaphysics, and particularly to the problems surrounding the origin, meaning, and nature of evil.

Literature: ROSKOFF, Gesch. des Teufels; HÖLEMANN, Reden d. Satan; OOSTERZEE, Christ. Dogmatics, 413 f.; SCHULTZ, Old Test. Theol. (Eng. trans.), ii. 269 f. The best account, in brief, is A. RÉVILLE, in Rev. des Deux Mondes, Jan. 1870 (Eng. trans., The Devil, 1877). (R.M.W.)

Dextrality [Lat. dexter, right]: Ger. Recht- (und Link-) händigkeit; Fr. dextralité (E. Nourry), droitier (et gaucher) (right and left-handed persons; no abstract terms in use); Ital. destrismo (e mancinismo) (right and left-handed persons). (1) The supremacy of the right hand, right-handedness.

(2) The fact of asymmetry of the hands, right- and left-handedness being special cases of it. (J.J.- J.M.B.)

For left-handedness, sinistrality is the corresponding word. The general bilateral symmetry of structure and function of the body is not complete; the most pronounced variation is in the superior development of the right side, particularly the hand. There is very generally a preferred foot as well as hand, and persons walking with their eyes closed are apt to manifest a tendency to circle quite constantly, some to the right, others to the left. There can be no doubt that left-handedness has always been exceptional, and right-handedness the normal. Even the relics of palaeolithic man indicate a predominant right-handedness, while historic records of the most ancient date give evidence of the recognition of the unusualness of left-handedness. Left-handedness however never fails to occur, although in varying proportions; it is sometimes stated as affecting about two persons in a hundred. Persons with equal facility in the use of either hand are termed ambidextrous; but even they prefer one or the other hand for the most accurate and delicate manipulations. In a striking number of cases ambidextrous persons are originally left-handed, but have acquired right-handed skill as well.

Of theories attempting to explain right-handedness, some refer it to the difference in position of the viscera, which favours a greater development of one side. Others regard it as determined mechanically by muscular advantage. Some emphasize the importance of education and acquired habit in the propagation of right-handedness; others regard it as an inborn difference. Amidst this diversity of opinion the best substantiated fact is this: that right-handedness and superiority of development of the left-cerebral hemisphere are the rule. Such superiority is evidenced by the fact that our speech faculties are more usually localized in the left hemisphere (see SPEECH AND ITS DEFECTS); while in a few exceptional cases of aphasia in left-handed persons the disease has been located in the right hemisphere. Brain weight is not a satisfactory test, but on the whole confirms the advantage of the left hemisphere; while a few cases of exceptional left-handedness, with greater weight of the right hemisphere, are on record. As to the explanation of the greater development of the left hemisphere, as determined by a better blood-supply, or by a general advantage of the left side in nutrition, &c., little that is definite can be offered. It is likely that the initial tendency to right-handedness is present in most persons, but in a slight degree, and that this slight tendency is so emphasized by education, and the social and industrial consensus, that in the end it is well marked. Some persons have a decided right-handed tendency, others an equally pronounced left-handed tendency, which resists all efforts to be corrected or brought into accord with the usual. Experiments on children as to original right- or left-handed tendencies are not sufficient to show positive results, but in some cases reveal a decided congenital right-handedness developing at a well-marked period. That animals are capable of preferential training for one side or the other has been demonstrated. (J.J.)

Literature: DANIEL WILSON, Left-handedness (1891); BALDWIN, Ment. Devel. in the Child and the Race, chap. iv; LOMBROSO, opera omnia, and the works of his school, on dextrality compared with left-handedness in normals, lunatics, degenerates, epileptics, criminals, &c. (cited under CRIMINOLOGY). See also ASYMMETRY. (J.J.- E.M.)

Diabolism: see DEVIL.

Diacoustics [Gr. dia + akoustikoV, pertaining to hearing]: Ger. Diakustik; Fr. diacoustique; Ital. dacustica. The science of refracted sounds; also called diaphonics. See HEARING (refraction). (E.B.T.)

Diagnosis [Gr. dia + gignwskein, to know]: Ger. Diagnose; Fr. diagnostic; Ital. diagnosi. The determination of the nature of a disease from its symptoms. Differential diagnosis refers to the comparative groupings of symptoms, whereby closely related conditions may be distinguished from one another.

Diagnosis forms one of the principal factors of practical medicine, and is no less important in regard to mental than to physical diseases. Symptoms to mental disorder, however, are particularly difficult to describe and explain, since the normal variation of mental traits is both large and indefinite. For examples of diagnosis, compare what is said of the diagnosis of insanity (under SANITY AND INSANITY), and the differential diagnosis of the different forms of aphasia (under SPEECH AND ITS DEFECTS). (J.J.)

Diagoras. Lived in the 5th century B.C. A Greek poet and philosopher, who followed Democritus of Abdera; he was born on the island of Melos, and became a citizen of Athens. He was called an atheist, because he rejected the popular religion, polytheism. He left Athens, 411 B.C., possibly banished for impiety. Died at Corinth.

Diagram (logical): see LOGICAL DIAGRAM.

Diagrammatic Reasoning: see REASONING.

Dialectic [Gr. dialektikh]: Ger. Dialektik, dialektisch; Fr. dialectique; Ital. dialettico, dialettica. (1) In ancient philosophy and logic: pertaining to reasoning or argument, and (as a noun) a system or course of reasoning or argument; (2) Kantian sense: see KANT'S TERMINOLOGY; (3) Hegelian sense: see HEGEL'S TERMINOLOGY, III, IV; (4) an extension of Hegel's usage: the logical statement of a thought or other process, considered as realizing itself in recurrent symbols or material forms. Cf. the writings of the Neo-Hegelian school (Wallace, Caird, Watson), to whom the respective definitions are personal interpretations of Kantian and Hegelian thought.

Literature: see extensive citations in EISLER, Wörterb. d. philos. Begriffe, 'Dialetik'; McTAGGERT, The Hegelian Dialectic. (J.M.B.)

Dialectics (in education). The art of teaching by means of discussion, as seen in Plato's dialogues, and involving, as with Socrates, inductive appeals to special instances. See METHOD (in education).

Literature: McMURRY, The Method of the Recitation, 221-32; XENOPHON, Memorabilia, Bk. IV. chap. ii; ROSENKRANZ, Philos. of Educ., 101-4.  (C.DE.G.)

Diallelon: see DIALLELUS, and TAUTOLOGY.

Diallelus [Gr. diallhloV, through one another]: CIRCULUS IN PROBANDO (q.v.). (J.M.B.)

Dialogic Method: see SOCRATIC METHOD.

Dialogism: see INFERENCE.

Diameter [Gr. dia + metron, a measure]: Ger. Durchmesser; Fr. diamètre; Ital. diametro. In craniometry several of the important maximal distances of the skull are termed diameters.

Certain of the most important of the cranial diameters are (a) the anterior-posterior, or maximum length from the most prominent point of the glabella to the occipital point (Gl, O of the illustration under CRANIOLOGY); (b) the transverse maximum, i.e. the greatest transverse diameter of the cranium wherever found; (c) the frontal, or width of forehead; (d) the maximum occipital, or greatest width of back of the head; (e) the vertical, giving height of the skull, or distance from the top or culminating point of the vertex (or by some, from the bregma) to the basion or middle of the anterior region of the foramen magnum (line Bg, B of the illustration under CRANIOLOGY). Many other diameters have been proposed as significant, some in the living head, as well as on the skull (see Gould's Dict. of Med., art. Diameter). The relations of a to b and others give rise to indices. See CRANIOLOGY, FACIAL ANGLE, and INDEX (also for Literature). (J.J.)

Dianoetic [Gr. dia + noein, to think]: Ger. Dianoetik, dianoetisch; Fr. dianoétique; Ital. dianoetico (suggested. -- E.M.). (1) Pertaining to the intellectual or reasoning function and processes. (2) Made by Hamilton to apply strictly to the discursive or elaborative faculty, in contrast with NOETIC (q.v.), which denoted cognitions (Lects. on Met., xxxviii). (J.M.B.)

In the first sense, Aristotle distinguished between the dianoetic and the ethical virtues. (K.G.)

Diaphonics: see DIACOUSTICS.

Diaspora [Gr. diaspora, dispersion]. The name given to the Jews dispersed throughout the Roman empire; also applied, by analogy, to a work carried on by Moravian missionaries, with the object of 'evangelizing' the state churches of the continent of Europe (Jas. i. 1; 1 Pet. i. 1).

Literature: SCHÜRER, The Jewish People in the Time of our Lord (Eng. trans.); KUENEN, Religion of Israel (Eng. trans.), iii. chap. xi; EWALD, Hist. of Israel (Eng. trans.), vi. 81f.; GRAETZ, Hist. of the Jews (Eng. trans.), ii. chap. viii; HAUSRATH, New Testament Times: The Times of the Apostles, I. div. ii. (Eng. trans.); MOMMSEN, Hist. of Rome (Eng. trans.), iv. 538 f.; MORRISON, The Jews under Roman Rule; HAVET, Le Christianisme et ses Origines, iii. (R.M.W.)

Diathesis [Gr. d a + tiqenai, to place]: Ger. Diathese; Fr. diathèse; Ital. diatesi. A constitutional predisposition of the body, whereby it is rendered specially liable to a certain disease; thus there may be a gouty, a diabetic, a phthisical, or an insane diathesis. The term has been extensively used with reference to mental conditions, and in this sense acquires much the same meaning as degeneration.

Persons with such a degenerate diathesis have a brain deterioration, which exposes them to insanity as the result of shock, of serious disturbance with the ordinary current of life, or at the critical periods of change of life -- dentition, puberty, childbirth, climacteric. Such persons are also characterized by unusual mental traits, a tendency to instability of character and action, as well as by bodily 'sigmata.' See DEGENERATION. In a somewhat different sense, the term is employed to indicate the milder forms of mental irregularity not amounting to distinct insanity.

Literature: MAUDSLEY, Pathol. of Mind (1895); CLOUSTON, Ment. Diseases (5th ed., 1898); KOCH, Die psychopathologischen Minderwertigkeiten (1891); MOREL, FÉRÉ, MAGNAN, as cited under MENTAL PATHOLOGY. (J.J.)

Dibatis, Dimaris, or Dimatis: see MOOD (in logic).

Dicaearchus. A Greek philosopher and writer of the 4th century B.C., who followed Aristotle. His history of the Greek people is extant, and one of the most important sources of biographical data.

Dichotomy [Gr. dica, apart, + temnein, to cut]: Ger. Zweitheilung; Fr. dichotomie; Ital. dicotomia. A form of logical division in which, at each step, the genus is separated into two species, determined by the possession and non-possession, the presence and absence, of a mark or attribute. The species so determined satisfy the rules of division: they exclude one another, and they exhaust the extent of the genus divided. As the process depends only on the formal relation between positive and negative terms, it has been called formal, and also exhaustive division.

Division by dichotomy first received recognition from Plato (especially in the dialogues Sophistes and Politicus), who, however, did not handle it from the purely formal point of view. His method is open to the objections urged against it by Aristotle (especially De Partib. Animal., i. chap. iii), and is certainly of no value for the practical ends of classification. The principle of the method lies at the foundation of Jevons', and indeed of all symbolic logic, for it is not dependent on the relation of genus and species, but expresses the fundamental distinction in thought between position and negation. (R.A.)

Dichromatism [Gr. diV, twice, + crwma, colour]: Ger. Dichromatismus(Rothblindheit, Grünblindheit, Blaublindheit); Fr. dichromatopsie (anérythropsie, &c.); Ital. cecità parziale pei colori. That deviation from normal colour vision, in which the colour distinctions of the spectrum are practically reduced to two; or, again, accepting as full and normal colour vision a range of colour which may be regarded as composable of three fundamental colours (trichromatic, Helmholtz) or four (Hering), the colour vision of a dichromatic eye would be composable out of two fundamental colours only. See COLOUR-BLINDNESS, VISION (visual sensation), and VISION (defects of). The term is used by Helmholtz. (J.J.- E.B.T.)

Dicta probantia [Scholastic Lat.]. A prominent phrase in the 'Biblical' section of the old dogmatic theology. It is used there of the 'proof texts,' so called; the dicta probantia furnish answer to the question, 'What does God's word teach us in Holy Scripture?'

Since the rise of the historical method, and the parallel development of historical theology and Biblical theology, this problem has come to be viewed and treated in a wholly new way.

Literature: ERNESTI, Institutio Interpretis Novi Testamenti. (R.M.W.)

Dictum: see MODALITY.

Dictum de Omni et Nullo: see ARISTOTLE'S DICTUM.

Didactics [Gr. didaktikoV, taught]: Ger. Didaktik; Fr. didactique; Ital. didattica. The science and art of teaching. See PEDAGOGICS, INSTRUCTION, and METHOD (in education). (J.M.B.)

Didactics (in theology). One of the sections of paedeutics which, in turn, is one of the main divisions of practical theology. Didactics is to be distinguished from catechetics. The former is the more extended use, and presupposes larger stores of knowledge. Religious education, as given by oral lecture to adults and to theological students, may be said to constitute the field of didactics. (R.M.W.)

Didascalic Syllogism: see SYLLOGISM.

Diderot, Denis. (1713-84.) French philosopher, born at Langres, educated by Jesuits, and intended first for the Church and later for the law. He eagerly embraced the study of literature. He became joint editor of the Encyclopédie with d'Alembert. He is considered chief of the sceptical philosophers called the ENCYCLOPEDISTS (q.v.). He died in Paris.

Difference [Lat. dis, apart, + ferre, to bear]: Ger. Unterschied; Fr. différence; Ital. differenza. The property of being distinguishable; that is, two mental objects or contents are said to be different, in certain features, for consciousness when in respect to those features one could not be taken for the other. Cf. LIKENESS, and INDIVIDUAL. The production of new differences in called Differentiation.

The case of numerical difference represents this criterion most plainly; for here the identification of the two contents as the same is prevented only by the fact of actual duplication of experience, as in the sight, handling, &c., of both objects at once, or by variations in the context. The absence of the experience of duplication -- together with all other 'features' within our definition -- would leave no room for difference. This is the psychological justification of Leibnitz' theory of the 'sameness of INDISCERNIBLES' (q.v.). (J.M.B.)

Difference (consciousness of): Ger. Unterschiedsempfindlichkeit; Fr. sentiment de différence; Ital. senso (sentimento) di differenza. Awareness of the presence of distinguishable aspects in a total experience either with or without singling out special constituents; it thus includes both DISCERNMENT (q.v.) and DISCRIMINATION (q.v.).

The use of the word Sense in this connection, with its foreign equivalents, is not be commended. It would be better to say Apprehension of Difference (with proper foreign equivalents). (G.F.S.- J.M.B.)

Difference (method of): Ger. Method der Differenz; Fr. méthode des différences; Ital. metodo delle differenze. The method of difference may be applied either in investigation, i.e. discovery, or in criticism of evidence, i.e. proof. In both cases the basis is the comparison of two complexes of circumstances differing only by the presence and absence of the phenomenon under consideration.

As conformity to this condition of exclusive difference is practically unattainable in observation, the method is pre-eminently that available in experiment where the exclusive difference can, so far, be introduced. Reasoning from the difference proceeds on the ground that for the change from presence to absence of the given phenomenon the explanation cannot be found in antecedent or conjoined circumstances which remain unaltered, but must be sought in those attendant, antecedent, or conjoined circumstances which exhibit the same change from presence to absence. The principle of this reasoning is the canon of the method as formulated by Mill: 'If an instance in which the phenomenon under investigation occurs, and an instance in which it does not occur, have every circumstance in common save one, that one occurring only in the former, the circumstance in which alone the two instances differ is the effect, or the cause, or an indispensable part of the cause, of the phenomenon' (Logic, Bk. III. chap. viii. § 2).

Literature: the term Method of Difference is due to J. S. MILL, Logic. The method and its principle had been recognized, and its general function defined, by FRANCIS BACON, Nov. Org., ii. Aph. 12; by HUME, Treat. of Human Nature, Bk. I. Pt. III. § 15; by HERSCHEL, Study of Nat. Philos., §§ 145, 156. On the limitations to the inference from the method of difference, see JEVONS, Pure Logic and Minor Logic, Works, 295 ff.; SIGWART, Logik, § 95; VENN, Empirical Logic, chap. xvii. (R.A.)

Difference (method of least noticeable): Ger. Methode der eben merklichen Unterschiede; Fr. méthode des modifications minima (Rouvier), or des différences à peine perceptible; Ital. metodo delle variazioni minime (Villa). See PSYCHOPHYSICAL METHODS.

It is recommended that the word 'noticeable' be retained in preference to 'perceptible' and 'distinguishable' (or the use of the phrase 'judgments of difference'), as being free from theoretical implications. (J.M.B.)

Difference Tone: Ger. Differenzton; Fr. son différentiel; Ital. suono di differenza, fenomenodel Tartini. The difference tone, or Tartini's tone, is the stronger of the two COMBINATION TONES (q.v.). It is usually defined as a tone whose vibration rate corresponds to the difference between the vibration rates of the primaries (Helmholtz, Sensations of Tone, 153). The work of König makes it probable that there are two difference tones: the one of the vibration rate b - a (where a is the vibration rate of the lower, and b that of the higher generator), and the other of the vibration rate 2a - b (König, Quelques Expériences d'Acoustique, ix, x, 1882); and that the one or other of these is audible, according to conditions (Ebbinghaus, Psychologie, 308).

It is producible: (1) by two tones; (2) by fundamental with overtone; (3) by overtone with overtone; (4) by tone and difference tone, &c. The difference tones from (4) onwards are difference tones of the second, third, &c., order. See BEAT TONES.

Literature: WUNDT, Physiol. Psychol. (4th ed.), i. 464; HELMHOLTZ, Sensations of Tone, 152; MEYER, Criticism of Current Theories and New Facts, Zeitsch. f. Psychol., xi. 177, xvi. 1; STUMPF, Tonspsychologie, ii. 229, 243 ff.; citations under SUMMATION TONE and BEAT TONE. (E.B.T.)

Differential: see CALCULUS.

Differentiation: see DIFFERENCE.

Differentiation (in biology) [Lat. differentia]: Ger. Differenzierung; Fr. différenciation; Ital. differenziamento. (1) The process by which the various parts of one cell acquire structural differences corresponding to a physiological division of labour. Seen more especially in the Protozoa. (2) The process by which the apparently similar, or undifferentiated, cells become different in structure and function. The latter is often spoken of as the physiological division of labour, and is necessarily accompanied by morphological differentiation. (3) The state reached by the above process, most strikingly exhibited in the development of the embryo into the adult organism. The differentiation of the tissues in ontogeny is termed histogenesis. For theories see EPIGENESIS, and PRE-FORMATION; see also DETERMINANT. On nervous differentiation see NERVOUS SYSTEM (II).

Literature: F. M. BALFOUR, Compar. Embryol.; OSCAR HERTWIG, Embryol. of Vertebrates (man and mammals), and The Cell (trans., 1895); KORSCHELT and HEIDER, Embryol. of Invertebrates; MINOT, Embryology. (C.LL.M.- E.S.G.)

Differentiation (in mathematics): the principle of the differential CALCULUS (q.v.).

Dignitas: see MAXIM.

Dignity: see WORTH.

Dilemma [Gr. diV, twice, + lhmma, something taken]: Ger. Dilemma; Fr. dilemme; Ital. dilemma. A composite form of conditional syllogism, sometimes called hypothetico-disjunctive, from combining the features of the hypothetical and the disjunctive syllogism; it is best defined as a syllogism having a hypothetical major premise with more than one antecedent and a disjunctive minor.

The dilemma in the earliest forms was regarded more as a rhetorical device than as a distinct type of logical reasoning. In this sense the alternative conditions were generally taken as two -- a positive and its negative -- one of which must be true, and which therefore could be laid down as alternatives in the minor premise; both entailed the same unpleasing consequent, which was then affirmed in the conclusion. The popular use of the word dilemma conforms to this first sense, but is reconcilable with the more elaborate analysis which has been given. There are considerable divergencies among modern writers as to the best mode of defining it (cf. Keynes, Formal Logic, Pt. III, chap. vi) (R.A.)

Dilemmatic: see PROPOSITION, and SYLLOGISM.

Dimaris: see DIBATIS.

Dimatis: see DIBATIS.

Dimension: see QUANTITY, and SPACE.

Diminishing (and Increasing) Return: Ger. fallende Produktivität, abnehmender (und zunehmender) Gewinn; Fr. loi de la culture, bénéfice diminuant (et croissant); Ital. produtività decrescente or profitto decrescente. (1) The obvious fact in agricultural production that, when a certain point of cultivation has been reached, increased application of labour and capital per acre does not produce correspondingly increased crops. (2) Any phenomenon in the relations between cost and return which has, or is supposed to have, some resemblance to the one just noted.

A comparison of return with cost will take various forms, according as we take different senses of the word COST (q.v.). We may compare either (1) income with expense; (2) utility with pain; or (3) production with waste.

If we spend more and more money in applying labour and capital to a given piece of land, we have at first an increasing return; then for a moment perhaps a constant return; and finally a diminishing return, as instanced in definition (1). The development of this principle is due to Turgot, Anderson, and Ricardo.

If we spend more and more minutes per day upon our work, we have up to a certain point increased efficiency, and increased surplus of pleasure over pain. Beyond that point, the utility of our consumption diminishes, and the pain of our labour increases; until finally a time comes when the added pleasure from what we can produce no longer balances the added pain of production. It is by an operation of this kind that the hours of labour are often determined. This analysis is due to Jevons. But it is not improbable that the actual determination of hours is based on waste rather than on pain. (A.T.H.)

Dimorphism [Gr. diV + morfh, shape]: Ger. Dimorphismus; Fr. dimorphisme; Ital. dimorfismo. The differentiation of the individuals of a species of animal or plant into two more or less divergent forms. (C.LL.M.)

The most familiar case is that of sexual dimorphism, where the males and females are divergent in form and character. In hymenopterous insects, such as ants and bees, the females are frequently dimorphic; the so-called queens being fully developed sexually, while the workers (so-called 'neuters') are imperfectly developed females -- the whole insect in each case showing structural differentiation. In butterflies we find seasonal dimorphism. When there are more than two forms the term polymorphism is employed, as in many animal colonies (Siphonophora and other colenterates) and groups.

Literature: AUGUST WEISMANN, Studies in the Doctrine of Descent (trans. by Meldola), and Germ-Plasm; E. B. POULTON, The Colours of Animals; E. HAECKEL, Natürliche Schöpfungsgeschichte (9th ed., 1898); D. SHARP, Insects, in Cambridge Nat. Hist. (C.LL.M.- E.S.G.)

Ding an sich [Ger.]; Fr. chose en soi; Ital. cosa in sè. A Kantian phrase for 'thing-in-itself' or 'noumenal' thing -- thing considered by which it is manifested. See THING, and NOUMENON. (J.M.B.)

Dioecious [Gr. diV + oikoV, a house]: Ger. zweihäusig; Fr. dioïque; Ital. dioico. A term applied to those plants, and often extended to animals, in which the sexes are distinct; as opposed to monoecious, where male and female organs are found in the same individual. The terms unisexual and hermaphrodite are more frequently used in zoology.

Linnaeus placed in his twenty-second class of Dioecia those plants which have the staminiferous and pistiliferous flowers on separate individuals. (C.LL.M.)

Diogenes. A Cynic philosopher, born in Asia Minor about 412 B.C. He was a pupil of Antisthenes, the founder of the Cynic school, and faithfully practised such tenets as 'that it is god-like to have no needs.' His heroic virtue and apathy to pleasures and pains have become world-famous. In his old age he is said to have been taken by pirates on a voyage to Aegina, where he was sold as a slave. Purchased by Xeniades, a Corinthian, he was first liberated and then hired as a tutor by his former master. Died at Corinth, 324.

Diogenes Laertius. A name connected with a fragmentary work entitled Lives and Doctrines of Famous Philosophers. Nothing is known of the author. But the work contains many biographies and stories, of more or less doubtful trustworthiness, together with many and valuable extracts. He probably lived in the 2nd century A.D.

Diogenes of Apollonia. A Greek philosopher, who lived in the 5th century B.C., and taught philosophy in Athens. Disciple of Anaximenes, he took air to be the first principle of things. See PRE-SOCRATIC PHILOSOPHY (Ionica).

Dion (or Dio) Chrysostomus. Born about 50 A.D. at Prusa, Bithynia. Greek philosopher and rhetorician. His surname (signifying 'golden mouth' or 'speech') was given him because of his eloquence. He shares to some extent the superficiality and insincerity of the Greek Renaissance, in which he lived.

Dionysius, Saint, called The Great. Born at Alexandria, latter part of 2nd century A.D.; died there 265. He was the assistant of Origen in the catechetical school in 233; bishop of Alexandria in 248; driven out of the city by persecution, 250; banished to Libya in 257; restored, 260. He was the most distinguished convert and pupil of Origen's school.

Diopter: see DIOPTRICS.

Dioptrics [Gr. dioptrikoV, pertaining to the use of the dioptra]: Ger. Dioptrik; Fr. dioptrique; Ital. diottrica. That part of the science of optics which treats of the refraction of light; opposed to Catoptrics. See VISION (light).

Diopter: the power of a lens with a focal distance of 1 m., the unit of measurement of lenses. For convex lenses it is written + D; for concave, - D (Helmholtz, Physiol. Optik, 2nd ed., 122). A lens of n diopters is one that has a focal distance of 1/n metres. (E.B.T.- C.L.F.)

Literature: HELMHOLTZ, Physiol. Optik (2nd ed.), 53 ff.; FICK, in Hermann's Handb. d. Physiol., iii. 1 ff.; AUBERT, Physiol. Optik, 393 ff. See KÖNIG'S Bibliography in Helmholtz's Physiol. Optik, 2nd ed. (E.B.T.)

Diplogenesis [Gr. diplooV, twofold, + genesiV, production]: Ger. (not in use); Fr. diplogenèse (rare); Ital. diplogenesi. An hypothesis according to which any influence which modifies the bodily tissues impresses on the germ-plasm of the individual a similar change, which is thus transmitted to offspring and rendered hereditary. The term was proposed by Cope in 1890 (see The Primary Factors of Organic Evolution, 1896). (C.LL.M.)

Diplopia [Gr. diplooV, double, + wy, eye]: Ger. Doppelsehen; Fr. diplopie; Ital. diplopia. Double vision; the condition in which an object is seen by one eye, or more usually by the two eyes, as two objects, and not as a single one. Monocular diplopia may be due to an imperfection of the media of the eye, or to retinal disease, resulting in dispersion of the rays of light; it can readily be produced artificially by holding a prism so that part of the rays reach the retina directly, and the others indirectly, through refraction.

The important forms of diplopia are binocular, which may be regarded as normal or physiological when it is experimentally produced by observing an object beyond or within the distance for which the eyes are converged, or by displacement of one eye, &c.; and it is pathological when due to a disturbance of the normal balance between muscles, by reason of paralysis or other cause. Such diplopia may be crossed (heteronymous), or direct (homonymous). As the image of the object seen falls in the fovea of the sound eye, it is distinctly seen by this eye; but as it falls in a peripheric region of the affected eye, it is there more or less indistinctly perceived. The former is called the true, the latter the false image. If the false image is on the same side of the true image as the affected eye is of the sound eye, the diplopia is homonymous; if on the other side, heteronymous. Either of these may be complicated by vertical diplopia, in which one image appears above or below the other, or the vertical diplopia may exist alone. According to the particular muscles affected, the diplopia assumes a special character, for the details of which consult the literature given below. It may be further noted that diplopia when slight may remain undetected, and the distinct image alone be attended to; and that false projection of objects in space may result from diplopia. See VISION (defects of).

Literature: GOWERS, Diseases of the Nervous Syst., ii. 169-80; NOYES, Diseases of the Eye, 140-3; PARINAUD, La Vision (1899); NORRIS and OLIVER, Syst. of Diseases of the Eye, iv. 3-167; BERRY, Diseases of the Eye (1893), 587. (J.J.)

Dipsomania [Gr. diya, thirst, + mania, madness]: Ger. Dipsomanie; Fr. dipsomanie; Ital. dipsomania, alcoolofilia (E.M.). An uncontrollable craving for alcoholic liquors, together with the abnormal mental symptoms which result from alcoholic excess. See ALCOHOLISM. (J.J.)

Direct and Indirect: see PREDICATION, PROOF, and INDIRECT VISION.

Direction [Lat. dirigere, to make straight]. Ger. Richtung; Fr. direction; Ital. direzione. That property of space whereby right lines from a common point of origin are differentiated from one another; applied figuratively also to other continua. (J.M.B.)

Direction (sense of). The more or less perfect and immediate localization of the regions of the external world with reference to oneself.

It is a special case of ORIENTATION (q.v.), the word 'sense' being used to cover that direct apprehension of direction which approaches the immediate character of a sensation. Its most marked development is in certain animals, e.g. homing pigeons, domestic dogs, &c., which are supposed to have such a sense, acting independently of the other senses. It is, however, becoming more widely the opinion that in these cases the animals follow either certain indications of sight, &c., or act reflexly upon organic stimulations such as temperature, humidity, and movements of air, as is the case with the migrating instinct in birds. Before adopting any general view, the actual performances of animals, under each type, should be treated statistically, with calculations of the number of failures or trials with error, with which the successes may be compared. With man, judgment of direction seems to be largely a matter of education and experience, resting, however, like all other functions, upon individual differences in aptness to learn. This would seem to be supported by the cases in which, as with the present writer, the ordinates of direction, lettered as points of the compass, are fixed by long custom at one's birthplace, and remain as a sort of mental scheme to impose themselves upon every new environment.

Literature: see the citations under ORIENTATION, and many of those given under INSTINCT; H. E. ZIEGLER, Zoolog. Jahrbücher, x. (1897) 254. (J.M.B.)

Direction (in optics): see LINE OF DIRECTION.


Disamis: see MOOD (in logic).

Disbelief: see BELIEF.

Discernment [Lat. discernere, to separate]: Ger. Merken; Fr. discernement; Ital. discernimento. Separate attention to a part of some kind of whole, simultaneous or successive, involving an elementary judgment of difference between the part singled out and the whole to which it belongs.

Discernment as here defined implies distinction of an object from its total context in experience, but not from another special object which is also singled out in like manner. See DISCRIMINATION.

Literature: CLAY, The Alternative, A Study in Psychology, 21. (G.F.S.- J.M.B.)

Discipline (in education) [Lat. disciplina]: Ger. (1) Erziehung, (2, 3) Disciplin; Fr. discipline; Ital. disciplina. (1) Primarily, and in the large sense, systematic training through education. (2) Secondarily, and in the restricted sense, the maintenance of authority by means of rewards and punishments. (3) A particular branch of study. See FORMAL CULTURE. (C.DE.G.)

Discontinuity (in biology). The view held by those who deny CONTINUITY (in biology) in any one of the four meanings enumerated under that topic. (J.M.B.)

Discontinuity (in logic): see MULTITUDE.

Discord [Lat. dis, apart, + cor, heart]: Ger. Missklung, Dissonanz; Fr. dissonance; Ital. dissonanza. See CHORD. (E.B.T.)

Discount [OF. disconter; Lat. dis, away, + computare, to count]: Ger. Disconto; Fr. escompte; Ital. sconto. The difference in value between the right to receive a thing at once and the right to receive it at some future time.

The difference between discount and interest is one of form rather than of substance. If A buys of B for $95 the right to receive $100 a year hence, the transaction takes the shape of a discount. If A loans B $95 with the provision that he shall receive at the end of the year $5 more than the original $95, the transaction takes the form of an investment with interest. But the legal and economic relations of the parties are exactly the same in the two cases. The ethical and philosophical questions involved in the transaction are discussed under INTEREST. (A.T.H.)

Discourse: an older term for the DISCURSIVE (q.v.) process. See also UNIVERSE (in logic). (J.M.B.)

Discovery [Lat. dis + cooperire]: Ger. Entdeckung; Fr. découverte; Ital. scoperta. The process (or result of the process) of attaining to a new truth, a fact or relation of facts not forming part of already established knowledge.

The term has a twofold implication: (1) of an ideal antecedent, a suggestion, preconception, or hypothesis; (2) of the establishment of the ideal antecedent as objectively true. Discovery is therefore most intimately connected with proof. It is often contrasted with INVENTION (q.v.).

Literature: WHEWELL, Philos. of Discovery (1860); G. GORE, Art of Scientific Discovery (1878). (R.A.)

Discrepancy: see HARMONY, and INCONSISTENCY (in logic).

Discrete [Lat. discretus, separate]: Ger. discret; Fr. discret; Ital. discreto. (1) Discontinuous (see CONTINUITY, and CONTINUUM).

(2) In logic: specifically but not generically different. Discrete notions are those which are co-ordinated under a more general notion. (J.M.B.)

Discrimination [Lat. discrimen, that which separates]: Ger. Unterscheidung, Distinction; Fr. discrimination, distinction; Ital. distinzione, discriminazione (Buccola). (1) A judgment of difference between two or more objects, each of which is discerned from the total context of experience at the time.

(2) Used for Consciousness of DIFFERENCE (q.v.) in cases of successive sensation, especially under experimental conditions, the full expression being SENSE DISCRIMINATION (q.v.). (G.F.S.- J.M.B.)

As between Discrimination (1) and Distinction, for which the foreign terms are common, there seems to be a subtle variation in the character of the judgment involved. Distinction has become a logical term, to indicate a more formal and verbal judgment of difference, in extreme instances resting on verbal identity, logical consistency, &c. -- 'a distinction without a difference' -- while judgment of discrimination has a more real or material reference, and with it a certain psychological appreciation. For example, it is more appropriate to say that I make a distinction between these two terms, than that I discriminate between them. The scholastics worked out many refinements in their distinctio essentialis, realis, formalis, quidditatis, &c., for which special histories should be consulted. (J.M.B.)

Discursive [Lat. discurrere, to run about]: Ger. discursiv; Fr. (pensée) discursive; Ital. (facoltà) discorsiva. Pertaining to the reasoning or logical function of the mind.

Discursive process is one which attains a result through a series of distinct steps, each logically depending on those which precede. It is used in opposition to INTUITIVE (q.v.), as applicable to knowledge which is not immediately apprehended. The discursive faculty is an early designation of the reasoning function. Hamilton speaks of the elaborative or discursive faculty (Metaphysics, Lect. xx. v). Cf. Kant, Pure Reason, trans. Micklejohn, 43. Ward uses the word intellection somewhat in this sense (Encyc. Brit., art. Psychology). Cf. INTELLECT. (J.M.B.- G.F.S.)

Disease [Ital. disagio, trouble]: Ger. Krankheit; Fr. maladie; Ital. malattia. While disease refers to any morbid deviation from normal health -- a disease of mind or body -- it refers specifically to a group of morbid conditions which affect the same part of the body and exhibit similar symptoms, such as a disease of the lungs, a disease of the brain, Bright's disease, a disease of the will.

An important distinction is drawn between organic or structural diseases, in which there is a lesion or pathological condition of some part of the body; and functional diseases, in which there is an irregular action of a part, but without any organic abnormality. Any malformation of a part of the body, or lack or excess of development, would form the basis of organic disease; while interferences with the circulation or digestion or the nervous processes would form the basis of a functional disease. Diseases are further considered as to their course, their classification, their symptoms, their diagnosis, their usual course or duration, their prognosis, and their treatment. These aspects are equally of importance in nervous and mental as in bodily diseases, and are in the main of medical rather than psychological interest. Illustrations of one or more of these terms in connection with mental diseases is given in the topics SANITY AND INSANITY, and SPEECH (defects of). The general scope of mental diseases is indicated in the topic MENTAL PATHOLOGY; see also ABNORMAL PSYCHOLOGY. (J.J.)

The great progress of mental pathology of to-day has been just that it has established distinct inherent diseases which have their regular evolution and their distinct existence. The great alienists of the past -- Pinel, Esquirol, &c. -- dealt mainly with symptoms. (L.M.)

Disharmony [Lat. dis + Gr. armonia]: Ger. Disharmonie; Fr. désharmonie; Ital. disarmonia. See HARMONY. (E.B.T.)

Disintegration [Lat. dis + integer, whole]: Ger. Desintegration; Fr. désintégration; Ital. disintegrazione. (1) A general word for all sorts of decay, decomposition, demoralization, the thought being that of a positive decline from a previous state to relative organization. (2) Spencer's use: see INTEGRATION AND DISINTEGRATION. (J.M.B.)

Disinterested Action: Ger. uneigennützige Handlung; Fr. action désintéressée; Ital. azione disinteressata. Action which is not determined by a view to personal pleasure or private interest.

The question concerning the nature and reality of disinterested action dominated the controversies of the English moralists. The discussion was started by Hobbes, who held that self-preservation, and the desire of power as a means to self-preservation, were the source of all human 'passions' or tendencies to action. The controversy centred round the 'disinterestedness' of benevolence, which Hobbes explained as due to desire of power, and Mandeville afterwards declared to be simply self-love in disguise. The chief opponents of Hobbes' view were Shaftesbury, Hutcheson, and Butler. Butler contended that 'disinterestedness' belonged not to benevolence only, but to all the primary impulses or 'particular passions'; these, he held, tend directly to an object, and not to the (personal or 'interested') pleasure of enjoying the object. This view was also adopted by Hume. Cf. ALTRUISM, BENEVOLENCE.

Literature: HOBBES, Elements of Law; BUTLER, Sermons; MANDEVILLE, Fable of the Bees; HUME, Princ. of Morals, App ii. (W.R.S.)

Disjunct and Conjunct: see MODALITY.

Disjunct Species: see SPECIES (in logic).

Disjunction: see DISJUNCTIVE.

Disjunctive [Lat. dis + iungere, to join]: Ger. disjunctiv; Fr. disjonctif; Ital. disgiuntivo. Disjunction, taken generally, is the name for the relation obtaining among the co-ordinate species of a genus; a disjunctive judgment, therefore, is one in which the assertion made is of such a relation. The relation may affect either the predicate (S is either P or Q) or the subject (either X or Y is Q), or a number of propositions (either A is true or B is true). The second type is either disjunctive in verbal expression only, or does not require to be distinguished from the third. The essential feature of the judgment is the presence of an expressed alternative. Probably it is desirable to recognize in the disjunctive, as in other types of assertion, a gradation from propositions which are highly concrete, of a kind often called divisive, to propositions of a highly abstract character. A disjunctive syllogism is generally defined as one in which the major is a disjunctive proposition and the minor a categorical proposition, restricting the indeterminateness of the alternation stated in the major.

Disjunctive judgments and syllogisms seem first to have been recognized by the peripatetic followers of Aristotle, who regarded them as forms of conditional argument. From the mere formal or grammatical point of view they were handled by the Stoic logicians, who tended towards placing them on a level with the hypothetical syllogism as a distinct genus. In modern logic, discussions regarding the disjunctive have concerned three points mainly: (1) whether and in what sense the disjunctive involves a special and independent general principle, e.g. as Kant maintained, the law of excluded middle; (2) whether the disjunctive assertion shall be interpreted as implying the exclusive character of the alternants stated; (3) how the disjunctive stands related to the conception of the contents of knowledge as a systematic whole.

Literature: PRANTL, Gesch. d. Logik, i. 386 ff., 446 ff.; KANT, Logik, §§ 27-9, 77-8; HAMILTON, Logic, i. 326 ff., ii. 369 ff.; KEYNES, Formal Logic, Pt. II. chap. ix, Pt. III. chap. vi; BRADLEY, Princ. of Logic, Bk. I. chap. iv; LOTZE, Logik, §§ 69, 71-4; BOSANQUET, Logic, Bk. I. chap. viii; LANGE, Logische Stud., chap. v. (R.A.)

Disorder (moral) [Lat. dis + ordo, order]: Ger. Immoralität, moralische Verdorbenheit; Fr. désordre moral; Ital. disordine morale. The state of man as possessing impulses to conduct inconsistent with morality.

The technical use of this term is mainly restricted to theologians, who regard this moral disorder as the effect of the Fall. The Fall, they hold, has made all mankind subject to evil, and (according to Calvinistic theologians) of themselves altogether incapable of any good. In this view the moral disorder amounts to total depravity. Goodness comes only from the supernatural grace of God; even the natural virtues (or what are called virtues) displayed by the spiritually unregenerate are not recognized as exceptions to this doctrine of total depravity.

The presence of moral disorder (in the sense of tendencies to evil) in human nature is a fact of universal experience. But the theory of the fact above given is only rendered necessary by the assumption that man was originally created perfect, and thereafter lost all power of well-doing. A history of human development has to show both how anti-moral tendencies have arisen and persisted, and also the gradual process of moralization. Cf. MORAL ORDER. (W.R.S.)

Disparate [Lat. dis + par, equal]: Ger. disparat, verschiedenartig; Fr. disparate, (sensations ou notions) hétérogènes (L.M.); Ital. disparato. 'Qualitatively distinct, as sensations of the different senses' (Herbart).

Wundt (Physiol. Psychol., 4th ed., i. 286) gives as criterion of disparate (or verschiedenartige) sensations the lack of intermediate stages or of continuous transition from one to the other, which occurs only in sensations of different senses; they are opposed to qualitatively similar (gleichartige) sensations, between which such a continuous transition is possible by variations in the stimulus (cf. Külpe, Outlines of Psychol., 278).

Disparate retinal points are points that are not 'identical.' See CORRESPONDING POINTS, and IDENTICAL POINTS. Cf. Wundt, Physiol. Psychol. (4th ed.), ii. 174. (J.M.B.- E.B.T.)

Disparate (in logic). A term applied to notions which do not fall within the sphere of any common notion (except of great generality), which have therefore no common elements of comprehension, though capable, at the same time, of having portions of their spheres common.

There has never been a fixed doctrine regarding the term disparate or its use. Cicero defines disparate as 'quod ab aliqua re per oppositionem regationis separatur, ut sapere, non sapere.' Boethius (cf. Prantl, Gesch. d. Logik, i. 686) begins the more modern tendency by defining 'disparate, quae tantum a se diversa sunt nulla contrarietate pugnantia.' The Aristotelian tradition is represented by Burgersdyk's definition, 'disparata sunt, quorum unum pluribus opponitur, eodem modo' (Inst. Log., i. 95; cf. Prantl, Gesch. d. Logik, iv. 52, 133). The definition here given corresponds to Leibnitz' treatment (Nouv. Essais, iv. 2, § 1), from whom it has found its way into the modern logics.

Literature: HAMILTON, Logic, i. 209-24; UEBERWEG, Logic, § 53; BRADLEY, in Mind, N.S., iv. (R.A.)

Disparity (logical): see DISPARATE (in logic).

Dispensation [Lat. dis + pensare, to ponder, requite]: Ger. Dispensation, Erlassung; Fr. dispensation, dispense; Ital. dispensa. Employed, in connection with religion, in two distinct senses: (1) An ethos or generally diffused set of ethico-religious circumstances under which humanity, or a portion of it, is said to live; e.g. the Mosaic dispensation -- ruled by the law; the 'gospel' dispensation -- ruled by GRACE (q.v.).

(2) After the Church had evolved its organization, a member who broke its rules or customs could be restored to fellowship only by repenting and penance. The latter became so severe in the course of time, that it could not well be enforced in all cases. The relaxation allowed by the Church is called a dispensation. It is now applied to any departure from established law or custom of the ecclesiastical organization, duly permitted by the recognized authorities. Theoretically, dispensation can be granted only in affairs relating to law recognized as 'human' by the Church. (R.M.W.)

Dispersal [Lat. dispersus, scattered]: Ger. Verbreitung, Ausbreitung; Fr. dissémination; Ital. disseminazione. The means by which the seeds, eggs, or embryos of sedentary plants or animals are distributed over a more or less wide area.

Dispersal forms an interesting and important subject of study in botany. It is effected by the wind, by water currents, and by animals. In many cases the seeds are provided with secondary structures, flattened expansions, plumes, hooks, spines, &c., by which dispersal may be furthered. In animals (such as molluscs and coelenterates) dispersal is generally effected by currents. In some river forms means are provided to check dispersal, which would entail the sweeping of the young out to sea. In some Protozoa the spores are dispersed by the wind.

Literature: CH. DARWIN, Origin of Species (1859); A. R. WALLACE, Island Life (1880); A. KERNER, Nat. Hist. of Plants; W. J. SOLLAS, On the Origin of Fresh-water Faunas, Trans. Roy. Soc. Dublin, ii, iii (1884). (C.LL.M.- E.S.G.)


Disposition [Lat. disponere, to dispose]: Ger. Disposition; Fr. disposition; Ital. disposizione. (1) An effect of previous mental process, or an element of original endowment, capable of entering as a co-operative factor into subsequent mental process. (2) A PREDISPOSITION (q.v.). Sense (1) is recommended. (G.F.S.- J.M.B.)

(3) Hering uses the term for the after-effect of general ADAPTATION (visual). (E.B.T.)

The term is applied both to consciousness and to nervous action (see the next topic). Dispositions are both congenital (as impulse or native tendency = PREDISPOSITION) and acquired (acquired tendency). In recent discussion (Lipps, Stout, Höfler, &c.) disposition has this broad meaning, while Einstellung applies to acquired tendencies, as in the 'setting' of the attention (Külpe, Outlines of Psychol., § 74, 4). On the mental side, the characteristic thing about disposition is its prepatory influence in the determination of subsequent states of mind. It represents impulse or habit under arrest. Considered with reference to the event towards which its determining influence is directed, it enters into expectation. In psychophysical experiments it shows itself in so-called ANTICIPATION (q.v.). The typical rise and gradual growth of an acquired disposition is a function of accommodation through a series of exercises. HABITUATION (q.v.) is applied to this process -- a translation of the German Einübung.

Literature: LIPPS, Grundthatsachen des Seelenlebens; STOUT, Analytic Psychol., i. and Manual of Psychol.; HÖFLER, Psychologie; WITASEK, Arch. f. sys. Philos., III, 1897, 273. (J.M.B.- G.F.S.)

Disposition (nervous). The tendency of a nervous centre, system, or element to function in a particular manner, either from native endowment or from previous functioning.

German physiologists use the word Bahnung, which includes the actual canalization (Waller) or anatomical path-making which results from continued nervous discharges in the same direction. Disposition has functional reference, and the English term FACILITATION (q.v.) has been suggested for Bahnung. (J.M.B.- G.F.S.)

According to Wundt, this functional disposition constitutes the physiological basis of ideational association (Physiol. Psychol., 4th ed., ii. 473), and therefore of retention. Inherited dispositions (see PREDISPOSITION) are the basis of instinctive actions. (E.B.T.)

Disputation: see OBLIGATIONS (in logic).

Dissent: see OBJECTION; and cf. ASSENT, and CONSENT.

Dissimilar (and -ity): see RESEMBLANCE AND SIMILARITY, WHOLE (logical).

Dissociation [Lat. dis + socius, a companion]: Ger. Dissoziation; Fr. dissociation; Ital. dissociazione. The process by which we come to discriminate within a whole components which have not been discriminated in previous experiences of this whole. (G.F.S., J.M.B.)

Dissociation (law of). When a and b have occurred together as parts of the same total object, without being discriminated, the occurrence of one of them, a, in a new combination, ax, favours the discrimination of a, b, and x from each other. 'What is associated now with one thing and now with another, tends to become dissociated from either, and to grow into an object of abstract contemplation by the mind. One might call this the law of "dissociation by varying concomitants"' (James, Princ. of Psychol., i. 506). See also Stumpf, Ueber den psychologischen Ursprung der Raumvorstellung, 130-4 (Unterschieden wird nur, was getrennt wahrgenommen worden ist, 132). (G.F.S., J.M.B.)

Dissociation (and Disaggregation, pathological): Ger. Dissoziation (Auflösung); Fr. dissociation (désagrégation); Ital. dissociazione (disgregazione). In general, dissociation refers to the converse of the processes of evolution or building up of functions of which life so largely consists.

Dissolution or degeneration exhibits the breaking down of more highly developed structures into simpler ones, the retrogression from a more highly complex and elaborate stage to a less developed one. Dissociation more specifically refers to special forms of mental abnormality of the type thus outlined.

Such abnormalities may be very slight in character, representing merely the momentary lapse of the most completely developed functions of the mind. When more grave they are frequently termed Disaggregation. In connection with the study of ATTENTION (q.v.), of HALLUCINATIONS (q.v.) and ILLUSIONS (q.v.), of disorders of PERSONALITY (q.v.), and of CONSCIOUSNESS (q.v.), states of dissociation and disaggregation are constantly met with. The main trend of conscious thought is apparently disintegrated, and a portion of the stream is dissociated from the rest; so that the subject, while in his normal state, is unaware of what has taken place in the abnormal or dissociated state; and in turn in the latter state seems but dimly conscious of his surroundings and his normal personality. From the momentary interruption of collected thought, known as abstraction or reverie, to actual hallucinations; from somnambulism and artificially induced states of hypnosis to hysteria and mania, the rôle of dissociation may be clearly recognized. What the nature of the process in the central nervous system may be, which brings about these changes, has been the subject of theoretical interpretation, which may be profitably considered in connection with the doctrine of personality and of hallucinations.

Literature: titles cited under the topics referred to above, especially the works of JAMES, PIERRE JANET, BINET, RIBOT; also PARISH, Hallucinations and Illusions (1897). (J.J.)

Dissonance [Lat. dis + sonare, to sound]: Ger. Dissonanz; Fr. dissonance; Ital. dissonanza. See CONSONANCE. (E.B.T.)

Distance: see EXTENSION, and SPACE.

Distance (visual perception of): see DEPTH.

Distinct and Distinctness: see CLEAR AND DISTINCT.

Distinct Term: see QUANTITY (logical).

Distinction: see DISCRIMINATION.

Distinguish: see DISCRIMINATION.

Distraction [Lat. dis + tractus, drawn]: Ger. Zerstreutheit; Fr. distraction; Ital. distrazione. (1) A state of distraction exists when a plurality of disconnected objects tend simultaneously to occupy attention, so that it cannot be effectively exercised upon any one of them. See ATTENTION (and defects of). (G.F.S.- J.M.B.)

(2) Pathological. There are several irreducible cases: (a) from ABSENT-MINDEDNESS (q.v.), from excessive concentration or preoccupation, possibly delusional; (b) from incapacity to concentrate steadily; (c) from too few or too many excitations badly systematized or in conflict among themselves. See Pierre Janet, Automatisme psychologique (1889), and État mental des Hystériques (1893). (L.M.)

Distraction of Attention (experimental): Ger. Ablenkung der Aufmerksamkeit; Fr. distraction de l'attention; Ital. distrazione dell' attenzione. A state of inattention artificially produced by positive stimulation of the attention to something else. (J.M.B.)

The state of inattention may be induced most easily by the supervention of a distracting stimulus upon an already existent state of attention. It is theoretically important that the state of inattention should be examined, since we wish to know what are the attributes of the simple processes given in that state, and what results the measurement of sensibility and sense discrimination yields during inattention as compared with the results gained during attention. The problem is, however, still very far from solution. It seems that only the error methods can be employed (see PSYCHOPHYSICAL METHODS), that the distraction must be continuous and must have a strong affective tone, and that scents fulfill the required conditions better than any other form of distracting stimulus hitherto tried. (E.B.T.)

In this article (and others) the terms 'sensibility' and 'sense discrimination' are substituted for SENSITIVITY (q.v.) and SENSIBLE DISCRIMINATION (q.v.) used by the writer. (J.M.B.)

Literature: BERTELS, Diss. (Dorpat, 1889); Papers in the Amer. J. of Psychol., by DANIELS, HAMLIN, MOYER, BIRCH, DARLINGTON, &c.; MÜNSTERBERG, Psychol. Rev., i; BINET, Rev. Philos., xxix. 138, xxx. 136; DE SANCTIS, Patol. dell' attenzione (1898). (E.B.T.)

Distribution (in biology) [Lat. distribuere]: Ger. Verbreitung, Verteilung; Fr. distribution géographique; Ital. distribuzione, bio-corologia. That branch of biology which deals with the distribution of animals or plants in space (chorology) and in time (chronology). In 1857 Sclater established six great zoological regions.

Literature: DE CANDOLLE, Géographie botanique (1855); ORTMANN, Marinengeographie; the works of SCLATER (1857 and 1899), A. MURRAY (1866), A. R. WALLACE (1876-80), A. HEILPRIN (1887), and F. E. BEDDARD (1897), on the Distribution of Animals; BAKER, Elementary Lessons in Botanical Geography (for the Distribution of Plants). (C.LL.M.- E.S.G.)

Distribution (in economics): Ger. Distribution; Fr. distribution; Ital. distribuzione. The economic process by which the shares of the product which go to labour, capital, natural agents, &c., are determined.

The analysis of price into rent, wages, and profits is very old, and is fully developed in Smith's Wealth of Nations. Ricardo showed the existence of certain peculiarities in regard to rent, and anticipated the form of modern analysis on this subject. J. B. Say (1803) made distribution a 'department' of political economy, co-ordinate with production and consumption. Most English writers have made a fourth department -- exchange.

According to the theory currently held, of which Marshall is the acknowledged exponent, there is in each year a net income or 'national dividend,' which is divided into component parts by economic laws, and which is capable of statical analysis. According to another theory, first developed by Newcomb, that which is distributed is essentially a flow rather than a quantity, and the attempt to analyse it by static methods involves great danger of fallacy.

Literature: MARSHALL, Princ. of Econ., i. (A.T.H.)

Distribution (in logic): Ger. Vertheilung, Distribution; Fr. distribution; Ital. distribuzione. The abstract name distribution now signifies in logic the state of a term in a proposition, in regard to its quantity. A term is said to be distributed, when it is taken universally; to be undistributed, when it is taken particularly.

The modern sense of the word distribution seems first to have been fixed by Petrus Hispanus (see Prantl, Gesch. d. Logik, iii. 60 f.), who defines it as 'multiplicatio termini communis per signum universale facta, ut cum dicitur "omnis homo," iste terminus "homo" distribuitur,' and thus restricts the application to terms taken universally. The earlier usage, from Cicero onwards, regarded distribution as the process of considering the effect of the quantifying additions by which a term was made universal in application. (R.A.)

Distribution of Errors: see ERRORS, and cf. VARIATION (statistical treatment of).

Distributive Principle: see SYMBOLIC LOGIC.

Disutility [Lat. dis + utilitas]: Ger. subjektive Kosten; Fr. perte d'utilité; Ital. inutilità (rare -- E.M.). The sum of the motives which tend to counterbalance the estimated utility of a line of conduct, and which, at the economic margin (see MARGINAL INCREMENT), are just equal to that utility.

The early writers on utility treated it as nearly synonymous with pleasure, and used pain as its antithesis. But utility can probably not be treated as equivalent to pleasure; and even if it could be, there is need of a word to express the counterbalancing motives more fully than pain does. For instance, in Jevons' Theory of Political Economy, we are led to infer that a man continues to work as long as the pleasure from the earnings is in excess of the pain involved; and that he stops at a point of indifference. But a number of other causes besides actual pain may lead him to stop; in other words, he may have an excess of pleasure in work at the stopping point. The pain plus these other motives -- in case they can be logically superadded -- constitutes the disutility; or, as Marshall calls it, 'discommodity.' (A.T.H.)

Diverse and Diversity: see RESEMBLANCE AND SIMILARITY, and cf. DIFFERENCE.

Divided Proposition, &c. (in logic): see MODALITY.

Divination: see MAGIC.

Divine Government: see GOVERNMENT (divine).

Divine Right: Ger. göttliches Recht; Fr. droit divin; Ital. diritto divino. Right conferred by God. The phrase is chiefly used to express the theory that kings hold their authority, not from the choice or consent of their subjects, but from God himself.

It has been the policy of nearly all rulers to represent their office as sacred: 'There's such divinity doth hedge a king' (Hamlet, iv. 5); hence their frequent alliance with religion. But the idea of divine right came most to the front in England in the 17th century, during the disputes of the Stuarts with the people. At the Restoration, 1660, it was the accepted Royalist doctrine. Sir Robert Filmer (in various writings from 1648 to 1680) based it on the partriarchal authority of Adam as father of the human family. His conclusion was that constitutional liberties were not rights of the people, but gracious concessions of the king. Filmer was answered by Algernon Sidney and Locke, the latter as champion of the Revolution of 1688. By 1760 the Tory doctrine had passed into an acquiescence in a de facto government. The older doctrine had an ephemeral revival at the time of the Holy Alliance, 1814, and it seems to be held by the present emperor of Germany. Cf. ABSOLUTISM, PASSIVE OBEDIENCE, MONARCHY. (J.B.)

Divine Type: Ger. göttlicher Typus; Fr. type divin; Ital. tipo divino. A quality or character of material things, which is regarded as expressing the divine character.

While the general thought is that of symbolism (see SYMBOL), it has been elaborated in detail by Ruskin (Mod. Painters, ii), by whom infinity is treated as the type of divine incomprehensibleness; repose as that of divine permanence; symmetry, of divine justice &c. (J.H.T.)

Divinity: see GOD.

Divisibility [Lat. divisus, from dividere to divide]: Ger. Theilbarkeit; Fr. divisibilité, Ital. divisibilità. The property according to which any quantity or whole is resolvable into parts, which remain parts of this whole.

The differentiae of the concept of divisibility consist (1) in actual resolution, not mere distinction, of parts. Many cases of QUANTITY (q.v.) admit, as quantities, of distinction of parts, while they cannot be resolved into these parts: such is a biological organism. (2) in resolution into parts which retain their quantitative relation to the whole. Chemical analysis, for example, does not illustrate divisibility -- except on the purely quantitative theory of atomic weights. So a mental whole or object is not divisible. Indivisibility is usually used not to cover all cases to which divisibility does not apply, but only cases of minimum, including infinitely small, quantities. Cf. the cross-references made under ATOM (various topics).

The problem of the divisibility of matter early arose to plague philosophers: cf. MONAD. That of finite and infinite divisibility constitutes one of the antinomies (cosmological) of Kant (Critique of Pure Reason, in loc.).

Literature: see the extensive citations given by EISLER, Wörterb. d. philos. Begriffe, 'Teilbarkeit.' (J.M.B.)

Division (logical) [Lat. dividere, to divide]: Ger. Eintheilung; Fr. division; Ital. divisione. The resolution of a genus into its constituent species, or the analysis of the extent of a general notion.

So defined, the process of division finds its theoretical lower limit at classes not presenting features, variation in which determines classes of less extent. Such classes were called infima species; they were the indivisibles or atoms in the Aristotelian scheme, and were regarded as natural kinds, types fixed in nature. In a less objective way the Aristotelian logic defines the superior limit, or summa genera -- classes of widest extent, in which therefore the determining marks are at a minimum. The process implies the rules: that the constituent species or dividing members in each division shall be determined by variation in respect to one and the same feature of the generic marks, called the fundamentum divisions; that the constituent species shall exclude one another; that the species shall exhaust the genus or divided whole. In a continuous series of divisions and subdivisions, it is also advisable to secure that the successive fundamenta divisionis selected should stand in a regularly descending scale of specification, ne fiat divisio per saltum. Cf. GENUS (in logic). (R.A.)

Division of Labour: Ger. Arbeitstheilung; Fr. division du travail; Ital. divisione del lavoro. The system under which different individuals, instead of labouring to supply each his own wants, specialize their production, and rely on the products of others for a large part of their consumption.

The system is described by Greek writers (Xenophon and Aristotle), and its workings were elucidated by Beccaria and Turgot. The name, 'division of labour,' is due to Adam Smith. Wakefield, Mill, and others have shown that division of labour is simply the most obvious among many forms of labour co-operation; and Wakefield went so far as to oppose the current use of the term as incorrect and misleading. In this last particular his ideas have not found acceptance. For the effects of division of labour see Smith, Wealth of Nations, Bk. I. chap. i. (A.T.H.)

Dizziness [AS. dysig, foolish, stupid]: Ger. Schwindelgefühl, Drehschwindel; Fr. vertige; Ital. vertigine. An organic sensation of whirling, lack of balance, and confusion primarily spacial. (J.M.B.)

It is set up by rotation of the body, sharp jerking of the head, the movement of a boat at sea, elevation above level ground, &c; to which may be added organic or functional troubles of the auditory apparatus (vertige de Ménière). There is also dizziness from stomachic and toxic causes -- from alcohol and poisons of many kinds. It is to be distinguished from the oesophageal sensation of nausea or sickness, which often accompanies it. Its seat is in doubt, but in some cases it is probably the ampullae of the semicircular canals.

The mode of origin of the sensation has been studied (1) by way of experiment upon deaf-mutes, controlled by autopsy, and (2) by rotation experiments made with the normal human subject. Vivisectional experiments upon birds and fishes (3) sustain the general conclusion that the canals constitute an organ for orientation, but furnish no evidence as to the presence or absence of sensation. See ORIENTATION, ILLUSIONS OF MOTION (2), and STATIC SENSE (also for Literature). (E.B.T.- L.M.)