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 Im - Ind

Posted August 2000

Image [Lat. imago, a likeness]: Ger. Bild; Fr. image; Ital. immagine. The mental scheme in which sensations or the sensory elements of a perception (or earlier image) are revived. The images of the mind taken collectively are known as imagery. Cf. IMAGINATION, and TYPE (mental). (J.M.B.- G.F.S.)

We speak of images of fancy, of memory, 'visual images,' 'auditory images,' 'tactual images,' &c. Cf. AFTER-IMAGE, and DOUBLE IMAGES. The image played a large part in the older associationist psychology, which taught that memory and recognition depend upon the comparison of the given presentation with its memory image. Recent experimental work and theories have established cases in which the image appears to play no essential part. (E.B.T.)

The theory of the mental DISPOSITION (q.v.) is proposed (by Stout, Meinong, Höfler, Ehrenfels) as a general way of accounting for many cases for which the associational-image theory is artificial; especially in the hands of those who make dispositions in the main motor tendencies and attitudes of interest, attention, &c. An interesting instance of the different points of view is seen in the experiments and discussions on the perception of time (see Schumann, in Zeitsch. f. Psychol., xvii. 106, and Meinong, ibid., xxi. 182), and the critical résumé and discussion by Stout (Perception of Change and Duration, Mind, N.S., Jan., 1900). (J.M.B.)

Literature: in general, the psychologies, under Memory and Recognition. Also BERGSON, Matière et Mémoire; TAINE, L'Intelligence, i. 76-165, ii. 70; N. MICHAUT, De l'Imagination (1876); F. GALTON, Inquiries into Human Faculty, 83-113; PARISH, Illusions and Hallucinations (1898); STOUT, Manual of Psychol., 393 ff. (L.M.)

Also STERN, Psychol. d. individuellen Differenzen (1900), 47 ff.; J. M. BALDWIN, Philos. Rev., ii. (1893) 385; J. M. CHARCOT, Œuvres complètes, iii (trans. by S. Freud, 1886, as Neue Vorlesungen ü. d. Krankheiten d. Nervensystems, insb. ü. Hysterie); G. T. FECHNER, Elemente d. Psychophysik ii. (1889) 469 ff.; F. GALTON, Mind, O.S., v. (1880) 301; W. LAY, Psychol. Rev., Monog. Suppl. 7 (1898); C. UFER, Ueber Sinnestypen u. verwandte Erscheinungen (1895). (E.B.T.)

Imagery: see IMAGE.

Image-worship (or Iconolatry) [Lat. imago, a copy]: Ger. Bilderdienst; Fr. culte des images; Ital. culto delle immagini, iconolatria. The paying of divine honours to an object which is supposed to be, in some sense, a likeness or imitation of the divinity for which it stands. See IDOL, and IDOLATRY.

Image-worship (or iconolatry) may be regarded as a species of idol-worship. An idol need not be a likeness or imitation of the divinity, but may represent it by mere association. It is the characteristic of an idol that it gradually displaces the divinity it represents, and tends to become itself the object of worship. This is true of image-worship, although its supposed resemblance keeps the thought of the object before the mind of the worshipper, tending to check the process of identification. The evil of image-worship arises out of the temptation to materialize the spiritual. Historically, image-worship is of ancient date, being forbidden in the second commandment of the Decalogue. The controversy over the use of images in worship has played a great rôle in the history of the Christian Church, leading at one time to a conflict which practically disrupted Christendom. The Romish Church is more tolerant of the use of images and pictures than the Reformed, while in the latter the Calvinistic communions are most uncompromising in their opposition.

Literature: GOLDAST, Imperialia decreta de cultu Imaginum (1608); MAIMBOURG, Hist. de l'Hérésie des Iconoclastes (1679); K. SCHENCK, Kaiser Leon III: ein Beitr. z. Gesch. d. Bilderstreites (1880). (A.T.O.)

Imagination: Ger. (1) Phantasie, (2) Einbildungskraft; Fr. imagination (constructive); Ital. immaginazione. (1) The general power or process of having mental images. See IMAGE, and IDEA. In this sense it seems better to use the terms imaging and imagery than imagination.

In its primary application imagination is simply equivalent to imaging, and is synonymous with the Greek fantasia. Hobbes defines it as 'nothing but decaying sense'; but he goes on to distinguish two kinds of imagination, the one simple, 'as when one imagineth a man or horse which he hath seen before'; the other compounded, 'as when from the sight of a man at one time and of a horse at another, we conceive in our mind a Centaur' (Molesworth's ed., iii. 6). According to Berkeley 'imaginatio nihil aliud est quam facultas representatrix rerum sensibilium, vel actu existentium vel saltem possibilium' (De Motu, § 53). With him both senses of the word are united. 'I find I have a faculty of imagining or representing to myself the ideas of those particular things I have perceived, and of variously compounding and dividing them' (Principles, Introd. 10). The connection is that we can image combinations that we never have perceived, and never will perceive. Similarly, in modern usage, it is customary to use imagination in both senses, and, where more precise distinction is required, to call the one reproductive, and the other productive, imagination. It seems better to adopt the current usage of popular language, and to restrict the term to that forming of new combinations which is made possible by the absence of objective limitations confining the flow of ideas (meaning 2).

(2) The process of forming new ideal combinations, which depends on the relative absence of objective restrictions, and the consequent freedom of subjective selection.

The mind is relatively unrestricted when it passes from sense-perception to its selective dealings with mental imagery. We can image combinations which we have never perceived. This relative freedom forms the connecting link between imagination in the sense of imagery and in the sense of free selective combination. Again, the man of science when he is looking for a possible explanation may 'give the reins to his imagination' in framing hypotheses; when the facts become more fully known, his freedom becomes correspondingly restricted. The imagination of the poet and the novelist is free from objective restrictions, inasmuch as their mental activity is not immediately directed to the development of knowledge of the real world, or to the attainment of practical ends.

There are two kinds of imagination: fancy, which is relatively passive, and constructive imagination, which is relatively active. Constructive imagination is dominated by a systematic unity of plan controlling the process of selective combination. It has what Coleridge called an esemplastic character (from eiV en plattein, i.e. to shape into one). Fancy, on the contrary, forms new combinations, which are relatively detached and sporadic instead of being integral parts of a whole. Coleridge quotes as an example of fancy the following verse from Hudibras:

'The sun had long since in the lap
Of Thetis taken out his nap,
And like a lobster boyl'd, the morn
From black to red began to turn.'
As an example of constructive imagination he refers to Milton's description of the approach of the Messiah to battle. The words 'far off their coming shone' gather the whole into the unity of a single picture. It is manifest that constructive imagination requires more sustained and strenuous activity than the mere play of fancy; for it can only utilize those suggested ideas which subserve the development of the general plan and enhance the total effect. Fancy, on the contrary, is free to pass from one combination to another with only a comparatively slight thread of connection, e.g. harmony, with the predominant mood, as gay, comic, pathetic, pensive, &c. The dividing line between constructive imagination and fancy is not sharply marked. There are border cases which may with equal show of reason be referred to either head.

Inasmuch as imagination is conditioned by absence of the objective control which belief essentially involves, belief and imagination are mutually exclusive. What is called aesthetic illusion or SEMBLANCE (q.v.) partly excludes the belief-attitude, and even 'reality-feeling.' The spectators at a theatrical performance do not act as they would if the same scenes occurred in real life. But it should be noted that the freedom from objective control which characterizes imagination is only comparative, not absolute, and that it admits of very varying degrees. Combinations which involve explicit contradictions are always excluded, even in the most unrestricted play of fancy. There are also almost always other objective limitations. So far as objective control exists at all, the attitude of belief (or reality-feeling) is present. A man may mentally frame a narrative concerning normal men and women which has no reference to any actual man or woman. 'The flow of his ideas will be relatively free; it will not be bound down by conditions of date, place, &c.; none the less it will be tied, inasmuch as he is not at liberty to introduce into his mental construction features at variance with the normal constitution of human beings. . . . There is no belief in the narrative as historical fact; but belief about human nature is involved in it through and through' (Stout, Manual of Psychol., 545 f.).

Literature: the treatises on psychology and BIBLIOG. G, 2, j; AMBROSO, L'Immaginazione (1898); RIBOT, L'Imagination créatrice (1900). (G.F.S.- J.M.B.)

Imaging (in logic): Ger. Abbildung; Fr. (in mathematics) représentation; Ital. rappresentazione. A term proposed to translate Abbildung in its logical use. In order to apprehend this meaning, it is indispensable to be acquainted with the history of the meanings of Abbildung. This word was used in 1845 by Gauss for what is called in English a map-projection, which is an incorrect term, since many such modes of representation are not geometrical rectilinear projections at all; and of those which Gauss had in view, but a single one is so. In mathematics Abbildung is translated representation; but this word is preempted in logic. Since Bild is always translated image, imaging will answer very well for Abbildung. If a map of the entire globe were made on a sufficiently large scale, and out of doors, the map itself would be shown upon the map; and upon that image would be seen the map of the map; and so on, indefinitely. If the map were to cover the entire globe, it would be an image of nothing but itself, where each point would be imaged by some other point, itself imaged by a third, &c. But a map of the heavens does not show the map itself at all. A Mercator's projection shows the entire globe (except the poles) over and over again in endlessly recurring strips. Many maps, if they were completed, would show two or more different places on the earth at each point of the map (or at any rate on a part of it), like one map drawn upon another. Such is obviously the case with any rectilinear projection of the entire sphere, excepting only the stereographic. These two peculiarities may coexist in the same map.

Any mathematical function of one variable may be regarded as an image of its variable according to some mode of imaging. For the real and imaginary quantities correspond, one to one and continuously, to the assignable points on a sphere. Although mathematics is by far the swiftest of the sciences in its generalizations, it was not until 1879 that Dedekind (in the 3rd edition of his recension of Lejeune-Dirichlet's Zahlentheorie, § 163, p. 470; but the writer has not examined the second edition) extended the conception to discrete systems in these words: 'It very often happens in other sciences, as well as in mathematics, that there is a replacement of every element w of a system of elements or things by a corresponding element w' [of a system W']. Such an act should be called a substitution. . . . But a still more convenient expression is found by regarding W' as the image of W, and w' of w, according to a certain mode of imaging.' And he adds, in a footnote: 'This power of the mind of comparing a thing w with a thing w', or of relating w to w', or of considering w' to correspond to w, is one without which no thought would be possible.' [We do not translate the main clause.] This is an early and significant acknowledgment that the so-called 'logic of relatives' -- then deemed beneath the notice of logicians -- is an integral part of logic. This remark remained unnoticed until, in 1895, Schröder devoted the crowning chapter of his great work (Exakte Logik, iii. 553-649) to its development. Schröder says that, in the broadest sense, any relative whatever may be considered as an imaging -- 'nämlich als eine eventuell bald "undeutige," bald "eindeutige," bald "mehrdeutige" Zuordnung.' He presumably means that the logical universe is thus imaged in itself. However, in a narrower sense, he says, a mode of imaging is restricted to a relative which fulfils one or other of the two conditions of being never undeutig, or being never mehrdeutig. That is, the relation must belong to one or other of the two classes, the one embracing such that every object has an image, and the other such that no object has more than one image. Schröder's definitions (however interesting his developments) break all analogy with the important property of the imaging of continua noticed above. If this is to be regarded as essential, an imaging must be defined as a generic relation between an object-class and an image-class, which generic relation consists of specific relations, in each of which one individual, and no more, of the image-class stands to each individual of the object-class, and in each of which every individual of the image-class stands to one individual, and to no more, of the object-class. This is substantially a return to Dedekind's definition, which makes an imaging a synonym for a substitution. (C.S.P., H.B.F.)

Imago [Lat.]: (the same in the other languages). The perfect or winged stage of those insects which pass through a complete METAMORPHOSIS (q.v.); it is in this stage only that the sexual organs are mature.

Literature: COMSTOCK, Introd. to the Study of Insects; PACKARD, Entomology; KORSCHELT and HEIDER, Entwickelungsgesch. d. Wirbellosen. (C.S.M.)

Imbecility [Lat. imbecillitas, weakness, feebleness]: Ger. Imbecillität, Schwachsinn; Fr. imbécilité; Ital. imbecillità. Generally, a weakness of mind; specifically, a degree of this defect inferior to idiocy.

It is applied more often to states of congenital mental enfeeblement. Imbecility may be said roughly to imply a sufficient defect of memory, reasoning, and mental initiation to incapacitate the subject for the ordinary duties of life and to make necessary a special form of education. Cf. IDIOCY. (J.J.)

Imitation [Lat. imitatio]: Ger. Nachahmung; Fr. imitation; Ital. imitazione. (1) The performance in movement, thought, or both movement and thought, of what comes through the senses, or by suggestion, as belonging to another individual.

This is the traditional and customary usage. It makes essential the fact that another person serves to set the copy imitated. This usage is that of Preyer and Lloyd Morgan. To distinguish imitation in this limited sense from the wider meanings designated below, it has been suggested that this be called 'conscious imitation' (when the repetition as such is conscious to the thought of the imitator), 'imitative suggestion' (when imitative to the onlooker only), and 'plastic imitation' (the subconscious conformity to types of thought and action, as in crowds).

(2) Any repetition in thought, action, or both, which reinstates a copy. This definition of imitation is wider than the foregoing. It includes what is called 'self-imitation,' or repetition of what is in one's own mind. This usage requires a certain identity as between the copy and the result made, but the conscious relating of copy to result, as in (1), is not essential. This usage is that of Tarde, James, Royce, Baldwin. As signifying simply 'mental reproduction' of nature, especially in art, it goes back to Plato and Aristotle. This usage is of value in discussions in social psychology, sociology, and the theory of art, as in the 'inner imitation' of K. Lange and Groos (for which see SEMBLANCE).

(3) An organic reaction of the stimulus-repeating or self-sustaining type. Organic imitation was used with this meaning as synonymous with CIRCULAR REACTION (q.v.) by the present writer. As this is a purely neurological and physiological conception, the use of the term imitation no doubt leads to confusion, and circular reaction expresses the meaning better. The question may then be discussed as to whether imitation always requires circular reaction.

As to the two first usages, it would seem to be wise to keep the broader meaning (2). Where ambiguity is likely to arise, it is well to use 'conscious imitation,' 'imitative suggestion,' 'self-imitation,' 'plastic imitation,' 'instinctive imitation,' all considered forms of the wider notion MIMETISM (q.v.), which covers also the pathological use of the term imitation. The wider meaning would seem necessary also as covering the imitative impulse before its character, as repeating a copy, becomes clearly conscious.

Distinctions have been made between 'spontaneous' and 'deliberate' imitation (Preyer), both being at first voluntary, but the former having become secondary -- automatic; and between 'simple' and 'persistent' imitation (Baldwin), the former being involuntary repetition by imitative impulse and suggestion, and the latter being voluntary 'try-try-again' to reproduce a copy. The need of recognizing a class of relatively simple reproductions of the imitative type is seen in the growing belief that there is a native impulse to perform acts of the imitative sort. A further distinction (Stout) is between 'impulsive' imitation, arising mainly from the direct impulse to imitate, and what may be called 'remote' imitation, springing from an ulterior motive.

Literature: psychological and biological: ARISTOTLE, Poetics, 4 ff.; J. S. MILL, Anal. of the Phenom. of the Human Mind (1829), ii. chap. xxiv; PREYER, The Mind of the Child (Eng. trans. and 4th Ger. ed.); BAIN, Senses and Intellect (3rd ed.), 413 ff., and Emotions and Will (3rd ed.), 344 f.; WALLACE, Natural Selection, v; LLOYD MORGAN, Habit and Instinct, chap. viii; GROOS, Play of Animals, in loc., and Play of Man, in loc.; ROYCE, Psychol. Rev., ii. (1895) 217, and The Imitative Functions, Century Mag., May, 1894; STOUT, Manual of Psychol., Bk. III. 269 ff.; BALDWIN, Mind, Jan., 1894, and the titles given below (general); LE DANTEC, Rev. Philos., Oct., 1899. Sociological: BAGEHOT, Physics and Politics; TARDE, Les Lois de l'Imitation; BOSANQUET, Mind, Apr., 1899, and Philos. Theory of the State, chap. ii. 3; DURKHEIM, Le Suicide, chap. iv; GIDDINGS, Princ. of Sociol.; TOSTI, Psychol. Rev., v. (1898) 247, and Polit. Sci. Quart., xii. 3; see also under CROWD. Neurological and pathological: PFLÜGER, Pflüger's Arch., xv (1877); citations made under MENTAL PATHOLOGY and MIMETISM. In art: PLATO, Republic, iii 400 B and D; ARISTOTLE, Poetics; works cited under ART THEORIES, especially titles by HEGEL, K. LANGE, v. HARTMANN, JOUFFROY, GROOS, GROSSE, BOSANQUET (Hist. of Aesth.); HIRN, The Origins of Art, chap. vi, General: TARDE, Lois de l'Imitation, and Social Laws (Eng. trans.); BALDWIN, Ment. Devel. in the Child and the Race, and Social and Eth. Interpret.; GROOS (titles cited above); WASHBURN, Philos. Rev. (Jan., 1899). (J.M.B., G.F.S.)

Imitation (in biology): see MIMICRY, and MINETISM.

Imitative Arts: see CLASSIFICATION (of the fine arts).

Immaculate Conception (dogma of): Ger. Lehrsatz der unbefleckten Empfängniss; Fr. dogme de conception immaculée; Ital. Immacolata concezione (dogma della). That the Virgin Mary, from her conception by her mother, Anne, became, by the grace of God, the subject of a peculiar application of the merits of Christ, whereby she escaped all taint of original sin.

A dogma of the Roman Catholic Church promulgated by Pope Pius IX in 1854. According to Roman Catholic doctrine, Mary, as Mother of God, has received certain privileges from the Deity. These are: perfect sinlessness, perpetual virginity, and the immaculate conception. As a matter of history, the Dominican doctors, especially Thomas Aquinas, opposed the doctrines of the privileges of Mary; in this they were supported by St. Bernard. But the Scotists revived the controversy and finally gained the victory. The doctrine of the immaculate conception is closely connected with the Roman Catholic view of Mary as a 'co-redeemer.' (R.M.W.)


Immanence (in theology) [Lat. in + manere, to remain]: Ger. Immanenz; Fr. immanence; Ital. immanenza. The indwelling and inworking of the Deity in nature and man.

Immanence as defined does not exclude TRANSCENDENCE (q.v.), and may coexist with it. But as often conceived, it is exclusive of that conception. Naturalistic and pantheistic conceptions of immanence are those which tend to identify the Deity completely with the inworking force of nature. This leaves no place for transcendence. It is possible, however, for God to work in nature, grounding its existence and phenomena, and yet to be something more in himself, to possess a being that is not identical with his operations. In this sense transcendence seems to be the presupposition of immanence. (A.T.O.)

Immanence-philosophy: Ger. immanente Philosophie; Fr. philosophie de l'immanence; Ital. filosofia dell' immanenza. The immanence-philosophy (philosophy of the immediately given or science of pure experience) is the doctrine of a group of recent German thinkers (Schuppe, Rehmke, Leclair, Schubert-Soldern, and others), who reduce all reality to conscious-contents or elements immanent in consciousness, and seek to explain the world therefrom (Eisler, Wörterb. d. philos. Begriffe, 371). In addition to the individual consciousness, some members of the school affirm the existence of Bewusstsein überhaupt, especially in order to escape the solipsistic consequences of their position. The doctrine has also been termed 'monism of consciousness' (Bewusstseinsmonismus). In certain respects it echoes Berkeley and Hume as well as Neo-Kantian and positivistic positions. (A.C.A.Jr.)

Literature: the Zeitsch. f. immanente Philos., founded 1895, is the organ of the school (see especially a brief account in Heft 1, by M. R. KAUFFMANN); UEBERWEG-HEINZE, Gesch. d. Philos., III. ii. 21 (8th ed., 1897); SCHUPPE, Logik, is the leading work of the school. (A.C.A.Jr.- K.G.)

Immanent and Transeunt Activity. Defining activity as any series of changes of a sufficiently regular and continuous character (see ACTIVITY, 2), the case may be looked at as of two general sorts: 'transeunt' activity, on the one hand, in which one object is acted upon by another; and 'immanent' or 'self'- activity, in which the changes observed take place within the active object with little or no influence from other things.

The activities of physical science are almost entirely of the transeunt sort: one body, molecule, atom, or system acts upon some other so that the results of the changes in the other are taken as a measure of the activity of the first. In the biological and mental sciences we have activity of the 'immanent' type: the series of changes seems to evolve within the organism or the mind, with a kind of determination called self-determination or immanence. They cannot be entirely or even largely construed as having been produced by the influence of things outside the organism or the mind. Theories, however, of life and mind turn just upon this question, as to whether both life and mind can be reduced ultimately to changes illustrating activity of the transeunt type; or, on the other hand, whether the activity of nature, which seems to involve the action of two or more separate things upon each other, may not be viewed as the immanent activity of a larger system of which the things are parts (Lotze), or interpreted after analogy with social community (Ormond). The controversy between freedom and determinism turns upon the interpretation of mental activity in answer to this question.

Literature: LOTZE, Metaphysics; STOUT, Analytic Psychol., i. Bk. II. chap. i; BRADLEY, Appearance and Reality, 95 ff.; ORMOND, Foundations of Knowledge, Pt. II. chap. vii; and the references given under ACTIVITY. (J.M.B.)

Immaterialism [Lat. in + materialis, material]: Ger. Immaterialismus; Fr. immatérialisme; Ital. idealismo spiritualistico, immaterialismo. Immaterialism is a term which has been applied chiefly to the theory of Berkeley, which asserts that 'nothing properly but persons does exist. All other things are not so much existences themselves as manners of the existence of conscious persons' (Commonplace Book, in Fraser's Life and Letters of Bishop Berkeley, 469).

It is considered more applicable than subjective idealism to such a theory, inasmuch as Berkeley accepts the trans-subjective reality of other finite spirits and of the Divine Spirit. It is only the material world whose substantial or independent existence he denies, its esse is percipi, or it exists simply as an ordered system of signs by which conscious beings communicate with one another. This system of signs, although it may be supposed to be conceptually present to the mind of God, by whom it has been instituted, has otherwise no reality for Berkeley except in the recurrent experiences of conscious beings. (A.S.P.P.)


Immediacy and Mediacy (Hegel's use): see HEGEL'S TERMINOLOGY, Glossary, 'unmittelbar,' 'Unmittelbarkeit,' 'vermitteln,' 'Vermittelung.'

Immediate and Mediate [Lat. in + medius, middle]: Ger. unmittelbar and vermittelt; Fr. immédiate and médiate; Ital. immediato and mediato. (1) Psychological: so far as new conscious process is a development of previous conscious process, it is said to be psychologically mediate; so far as it is determined by conditions independent of previous conscious process, it is said to be psychologically immediate. The corresponding substantives are immediacy and mediacy.

Speaking psychologically, careful analysis seems to show that no knowledge is purely immediate or purely mediate. All cognition is both immediately and mediately determined. Immediacy is a characteristic belonging most conspicuously to the perception of external objects or the apprehension of subjective processes. But the immediacy is never pure immediacy; it is inextricably blended with the self-development of mental process. The play of external impressions on the organs of sense contributes an element of immediacy to all sense-perception. But this is only one factor in the process. Previous experience also contributes to the result and determines its nature. I raise my eyes from my book and look out of the window. There on the grass I see a robin hopping about. No previous experience of mine could have enabled me to predict that a robin would present itself at this time and place. There is an immediacy in the cognition which cannot be explained away. But critical reflection shows that there is also a mediacy which is equally indispensable. It is owing to previous experience that I am able to distinguish and identify the object I call a robin, or even the red colour of its breast. Even the shape and distance of things seen exist for my consciousness only as an outcome of my previous mental development. But can we not push our analysis further so as to extract from the total experience the immediate element, the pure datum, and exhibit it in isolation? The attempt is worth making; but its value will be found in its failure, not in its success. The first step we must take is to pass from external to internal apprehension. In asserting the actual presence of the external thing as such, there is always an element of mediacy and a theoretical possibility of error. We may be subject to an illusion or hallucination. In the pursuit of pure immediacy we must retire into the citadel of our own self-consciousness. I affirm not that there is a robin, but that I see or think I see one. But even this is not purely immediate knowledge. The mere appearance of a robin as contrasted with the reality presupposes the identification of this object in distinction from others. Moreover, when I affirm that I see, or think I see, I must have learnt to discriminate those modes of consciousness which I call thinking and seeing from other modes of consciousness. Besides this, it is important to note that 'thinking' and 'seeing' mean more to some persons than to others. They mean more to those who have studied and analysed these processes than to those who have not, just as the sight of a robin means more to a naturalist than to those who are not naturalists. But the fuller of meaning perception is, the larger is the part played in it by interpretation based on previous experience. This is a point of the utmost importance. The more purely immediate a cognition is, whether it be of material things or of subjective process, the more meagre and empty it is, and the less value it has for the system of knowledge as a whole. The attempt to discover an absolutely pure datum of consciousness, without psychological preconditions -- a matter of fact which is pure and immediate -- ends in the discovery of nothing at all, or of something quite insignificant. The immediacy of internal cognition, like the immediacy of external perception, is valuable, not in itself, but because of its relation to the work of the mind. It is valuable only in so far as it confirms, modifies, corrects, or overthrows that body of inferences which constitute the system of knowledge as a whole.

But if no knowledge is, in a psychological sense, purely immediate, we have still to inquire if any is purely mediate. It will be granted that all knowledge psychologically presupposes data as its point of departure which are not mere products of subjective process. But it may be said that, given certain data, we can evolve further knowledge from them without the aid of fresh data. Given the general constitution of the number-series, we can deduce a multitude of consequences without any further datum. This is true in the sense that no further datum is required which is not contained in the constitution of the number-system itself. But the nature of this system reveals itself gradually in the process, and each new revelation may be regarded as a fresh datum which we do not make, but find. We exercise subjective activity on the object, but the result depends on it, and not on us. In this sense all experience partakes of the nature of experiment, whether it be trying the taste of a fruit, or following the dialectical transitions in Hegel's logic. (G.F.S., J.M.B.)

(2) Psychical or mental: the immediacy or mediacy of an experience, either in a psychological or in a logical sense, (1) or (3), as it exists for the subject of that experience at the time at which it occurs.

We may distinguish two forms, which may or may not coexist. The first has reference only to cognition as such. Psychical immediacy from this point of view consists in the absence of conscious inference, and mediacy consists in the presence of conscious inference. A cognition which is psychically immediate enters the consciousness of the subject without any recognition of its dependence on other cognitions. The second kind of psychical immediacy consists in the absence of reference, not to reasons for a belief, but to the psychological conditions of the experience. For example, we usually accept ideas as they occur without inquiry into the mode in which they suggest each other by association: we are not continually asking -- 'What made me think of that?' If we do ask this question, the occurrence of our ideas becomes psychically mediate in the second sense. (G.F.S.- J.M.B.)

The force of the distinction between (1) and (2) is seen in the cases of perception, &c., given under (1), in which the psychologically mediate is taken to be (i.e. is, psychically) immediate. The difference between (1) hallucinatory and (2) strict sense illusions is that between the presence of (1) psychical and (2) psychological elements of immediacy. As is said above, the psychically immediate is not always psychologically so; and it is also true, though not so frequent, that the psychologically immediate is not always psychically so. For instance, pathological emotions, due to organic causes, which the patient 'justifies' by the belief in persecution, possession, &c., have elements of psychological, but not of psychic, immediacy. Cases within the sphere of cognition are furnished by hypnotic, and more clearly by post-hypnotic, or deferred, suggestion. Cognitions of various sorts are 'immediate' suggestions in the psychological sense; but are 'accounted for,' 'justified,' 'explained' by the subject; that is, they are psychically mediate.

The distinction between (1) and (2) is the general one between PSYCHIC AND PSYCHOLOGICAL (q.v.). Cf. the two headings in the case of ANALYSIS. It is important in this case, notably for ethics, the discussion of the immediacy of ethical value being confused by the failure to make the distinction, a confusion which the use of the undefined terms 'derived' and 'immediate' only accentuates. Its epistemological value also becomes evident when one recalls the use of the notion of immediacy as one of the TESTS OF TRUTH (q.v.), under such phrases as 'self-evidence,' 'direct intuition,' &c. It is difficult to see how mere psychical immediacy to the individual -- at its purest in sensation and intense feeling, that is, in anoetic consciousness -- can be taken as a test of validity in what is over-individual and absolute; for it does not even guarantee psychological immediacy. And even if it did, the question would remain as to whether immediacy in any form is not the purest sort of relativity.

Kant, while showing this fallacy in the case of ideas of the reason, nevertheless makes similar use of the psychical immediacy of the practical reason. Spencer's criticism of immediacy of both sorts -- as being a function of race adaptation and not necessarily avoiding, but to him requiring, an agnostic position -- goes to show that the resort to immediacy in epistemology is everywhere futile. The latest reasoned appeal to it is that of Bradley, who, like Kant, though for different reasons, fails to find comfort in the mediate. The FAITH PHILOSOPHY (q.v.), down to its recent advocacy of the 'will to believe,' always puts its trust in some data of psychical immediacy. Ultra-rationalism or intellectualism which deduces its absolute makes much appeal to mediacy, but is in turn criticized by positivists for not going the whole way. Cf. Ormond, Foundations of Knowledge, Pt. I. chap. iii. (J.M.B., G.F.S.)

(3) Logical or epistemological. From a logical or epistemological point of view a cognition is immediate when it requires no proof; and it is mediate when it requires proof.

I see an ink-pot before me on the table: I perceive it as having an existence distinct from and independent of my own existence, both bodily and mental. This cognition is psychologically mediate inasmuch as it is a product of previous mental process. Psychically it is immediate, inasmuch as I am not aware, in the moment of perception, of its dependence on grounds or reasons. But let some one question or deny that the ink-pot exists as I perceive it. I may then think it necessary to justify my perceptual judgment by assigning reasons for it. I may begin by saying that the ink-pot exists in the manner I affirm, because I perceive it as existing in this manner. This is to assign a psychical fact as the logical ground of a physical fact. The doubter may then proceed to unmask the whole battery of subjective idealism, and bombard my position. In the end I may find it necessary to develop a series of complicated arguments to establish what, in the first instance, came before consciousness as an immediate datum. In taking this course I admit that what was the psychically immediate datum really required justification by grounds and reasons. In other words, I admit that it is logically mediate. On the other hand, I might have adopted a different course. I might have resolutely refused to argue, affirming that the existence of the inkstand is for me a self-evident fact which requires no proof, and that all arguments to the contrary must, from the nature of the case, be irrelevant or nonsensical. I should then be maintaining that my perceptual judgment is logically immediate. Cf. KNOWLEDGE (in logic).

Literature: see EPISTEMOLOGY, and BIBLIOG. B, 1, d. (G.F.S., J.M.B.)

Immediate Creation: see CREATION.

Immediate Inference: see INFERENCE.

Immensity: see ATTRIBUTES (of God).

Immortality [Lat. in + mortalis, mortal]: Ger. Unsterblichkeit; Fr. immortalité; Ital. immortalità. The doctrine that the human soul survives the death of the body, and is the bearer of an endless life.

Belief in immortality, in some vague form at least, has been a feature of most religions, although it is perhaps only in Christianity that it has become an assured conviction. In the Greek mysteries, notably the Eleusinian, it is taught rather by implication than dogmatically. In philosophy it has played a prominent part. Plato held the doctrine and developed a number of proofs of immortality, connecting it in his eschatology with the process of metempsychosis. Aristotle's doctrine of the perishability of the passive intellect leaves the attitude of his philosophy towards personal immortality in doubt. The Stoics taught a doctrine of limited immortality. Mediaeval thought divided on Aristotelian grounds, the Arabians tending to deny, while the leading schoolmen affirmed, personal immortality. In modern thought the question became involved with that of the substantiality of the soul. On the soul's knowledge of itself as a substance Mendelssohn's famous proof of immortality is founded. Kant refutes this proof by calling in question the presupposition on which it rests -- namely, the soul's ability to know itself as a substance. Kant founds his own proof of immortality on the demands of the moral reason. Since Kant the tendency has been gaining strength to rest the doctrine of immortality mainly on moral and aesthetic grounds, or on what Lotze calls considerations of value. The most recent tendency is to ground the persistence of the individual soul in its relation to God on the Absolute.

Literature: W. R. ALGER, A. Crit. Hist. of the Doctrine of a Future Life (1871); W. E. CHANNING, on Immortality, in Essays (1839); PLATO, Phaedo, and the Apology; G. TEICHMÜLLER, Über die Unsterblichkeit d. Seele (1874); E. ABBOT, Literature of the Doctrine of a Future Life; LOTZE, Microcosmus; Ingersoll Lects., by JAMES and ROYCE. (A.T.O.)

Immutability [Lat. in + mutabilis, changeable]: Ger. Unveränderlichkeit; Fr. immutabilité; Ital. immutabilità. Changelessness. A theological term used to designate the attribute of changelessness in the divine nature. See ATTRIBUTE (of God), and ABSOLUTE. (J.M.B.)

Impenetrability [Lat. in + penetrabilis, penetrable]: Ger. Undurchdringlichkeit; Fr. impénétrabilité; Ital. impenetrabilità; That property of matter by virtue of which every portion or particle of it prevents any other portion or particle from occupying the same space with itself at the same time.

It is known by universal experience that, whenever the attempt is made to bring two masses of matter into the same position, an irresistible force comes into play which prevents coincidence. The masses with which we are most familiar, solid and liquid bodies, seem to us to have definite boundaries, forming geometric surfaces; and the force in question comes into play instantly when two such surfaces are brought into contact. To this familiar fact the conception of the parts of matter in general, how minute soever they may be, as having extension in space and absolute impenetrability may be supposed due. But careful analysis does not justify the conclusion that the properties of extension and impenetrability grow out of the fact that the parts of matter have absolutely definite boundaries. The really observed phenomenon is that of a repulsive force coming into play when two particles are brought into apparent contact. We may therefore, with Boscovisch, abandon the idea of a definite boundary to the parts of matter, and consider the latter as simple centres of attractive and repulsive forces acting at distances so minute as to elude our senses.

Impenetrability thus becomes a secondary quality arising from an unlimited increase of the repulsive force as two centres are brought nearer together. (S.N.)


Imperative Idea or Conception, also Insistent Idea: Ger. Zwangsvorstellung; Fr. obsessions, impulsions intellectuelles; Ital. idee coatte (or coartanti), ossessione. An idea or train of thought which dominates or harasses the individual in spite of his struggle to escape from it and his recognition of its unreasonableness.

The imperative idea is not a DELUSION (q.v.) nor a FIXED IDEA (q.v.), which actually moulds the individual's intellectual processes; but it is rather an idiosyncrasy, the nature of which the victim fully recognizes but seems powerless to dispel. It is not a form of insanity, but seems associated with unstable or susceptible nervous conditions. The experience is a common one of being annoyed by the frequent occurrence of a word, a line of verse, a train of thought, a suggestion to say or do some trifling absurdity or impropriety; and the imperative idea is only the more marked and established form of such an idea or habit. It is related psychologically to conditions of impairment or weakness of will (see WILL, diseases of); and the imperative idea may at times prevent or check normal action, or incite to actions which it is the purpose and policy of the individual to inhibit. Examples of imperative ideas which affect both thought and action are: agoraphobia, the nervous dread of open places; claustrophobia, the dread of shut-in places; arithmomania, the impulse to count all sorts of objects and speculate uselessly and endlessly on numerical relations. Such tendencies as coprolalia, the impulse to use blasphemous or obscene expressions; and such habits of thought as constant speculation about intellectual trifles, fear of contamination in the slightest and most exaggerated forms, may come to dominate so much of the intellectual processes as to approximate to a condition of insanity. It is to be noted that these unwelcome but insistent ideas (well characterized by the German Zwangsvorstellung) often cause intense fear, worry, and anxiety, even when they do not influence action; the patient fears that he may yield to certain impulses, and maintains a struggle against a habit which he recognizes to be absurd. Rather few of the imperative ideas are purely intellectual, most of them being related to morbid motor impulses. Those that are sensory may be regarded as similar to SYNAESTHESIAS (q.v.) or Zwangsempfindungen, or the inevitable association of one sensation with another; while those which are entirely motor become nothing more than eccentric habits; e.g. the trick of feeling some obligation to touch with a cane every post or tree, or some particular object on an accustomed walk. What is common to all cases is a bondage or impulse which the victim feels 'to pursue a certain trivial or disagreeable line of thought, often associated with vocal utterance, or motor acts (and with emotional disturbance, such as fear, anxiety), along with sanity in other respects' (Tuke).

Literature: art. Imperative Ideas in Tuke's Dict. of Psychol. Med., and literature there cited; MICKLE, Obsessions and Besetments, J. of Ment. Sci. (1896), x1ii. 691; THOMSEN, Lehre von den Zwangsvorstellungen, Arch. f. Psychiat., xxvii (1895); KRAFFTEBING, Arch. f. Psychiat. (1890), 68, 529 ff.; JANET, Névroses et Idées Fixes (1898); TUKE, in Brain (1894), xxii. 179-97; JACKSON (and others), in Brain (1895), 318-51. See also works of MAGNAN, KOCH, LEGRANDDE-SAULLE, and MORSELLI, as cited under DOUBTING MANIA, and DEGENERATION. (J.J.)

Imperceptible [Lat. in + percipere, to perceive]: Ger. unmerklich; Fr. imperceptible; Ital. impercettibile. Applied to stimulations or differences of stimulation which are too weak to be distinguished by consciousness.

Such stimulations are said to be below the conscious THRESHOLD (q.v.), as those which are 'least or just noticeable' are just above it. The discussion as to whether there are sensations which are imperceptible is not raised here. Cf. UNCONSCIOUS. (J.M.B., G.F.S.)

Impersonal Judgment: see PROPOSITION.

Implicate and Implication: see IMPLICIT AND EXPLICIT.

Implicit and Explicit: Ger. miteinbegriffen, implicit (Implikation), and ausdrücklich, explicit; Fr. implicite (implication; means also contradiction -- TH.F.) and explicite; Ital. implicito and explicito. That which is outwardly, definitely, or expressly included in any whole is explicit to the whole; that which belongs to a whole but is not explicit is implicit to it.

Inferable, nascent or incipient, immanent, all present shades of meaning expressed in various contexts by implicit. That which is, especially logically, implicit is called an implicate or an implication. Both implicit and explicit are applicable in particular to wholes of meaning or intent. Cf. the next topic. (J.M.B.)

Implicit (in logic). Said of an element or character of a representation, whether verbal or mental, which is not contained in the representation itself, but which appears in the strictly logical (not merely in the psychological) analysis of that representation.

Thus, when we ordinarily think of something, say the Antarctic continent, as real, we do not stop to reflect that every intelligible question about it admits of a true answer; but when we logically analyse the meaning of reality, this result appears in the analysis. Consequently, only concepts, not percepts, can contain any implicit elements, since they alone are capable of logical analysis. An implicit contradiction, or contradiction in adieto, is one which appears as soon as the terms are defined, irrespective of the properties of their objects. Thus there is, strictly speaking, no implicit contradiction in the notion of a quadrilateral triangle, although it is impossible. But, owing to exaggeration, this would currently be said to involve not merely an implicit, but an explicit contradiction, or contradiction in terms.

Any proposition which neither requires the exclusion from nor the inclusion in the universe of any state of facts or kind of object except such as a given second proposition so excludes or requires to be included, is implied in that second proposition in the logical sense of implication, no matter how different it may be in its point of view, or otherwise. It is a part of the meaning of the copula 'is' employed in logical forms of proposition, that it expresses a transitive relation, so that whatever inference from the proposition would be justified by the dictum de omni is implied in the meaning of the proposition. Nor could any rule be admitted as universally valid in formal logic, unless it were a part of the definition of one of the symbols used in formal logic. Accordingly, whatever can be logically deduced from any proposition is implied in it; and conversely. Whether what is implied will, or will not, be suggested by the contemplation of the proposition is a question of psychology. All that concerns logic is, whether all the facts excluded and required by the one proposition are among those so excluded or required by the other. (C.S.P.)

Import [Lat. in + portare, to carry]: Ger. Bedeutung; Fr. portée, signification; Ital. importanza, significato. Import is almost synonymous with signification or meaning. It is therefore used in logic as equivalent to COMPREHENSION (q.v.), e.g. in the case of notions. In reference to judgment, import must be taken to mean the precise thought-relation which is asserted, positively or negatively, in the judgment. Cf. JUDGMENT. (R.A.)

Impregnation: see FERTILIZATION.

Impression [Lat. impressus]: Ger. Eindruck; Fr. impression; Ital. impressione. (1) Used by Hume to designate experiences of the perceptual order as contrasted with 'ideas' (fainter revived impressions).

(2) The physiological process of stimulation apart from the corresponding sensation which it arouses.

(3) In sociology: sometimes used for CONSTRAINT (q.v.). (J.M.B., G.F.S.)

Impression (aesthetic). The effect produced by the intrinsic qualities of an aesthetic object, as distinguished from its expression or suggestion of a meaning pointing beyond itself.

For example, the impression of a straight line as compared with that of a curve, and the impression of either of these as compared with the expression of a face, whose features chanced to contain both (cf. Santayana, The Sense of Beauty, 1896). See IMPRESSIONISM. (J.R.A.)

Impressionism [Lat. impressio, from in + premere, to press in or upon]: Ger. Impressionismus; Fr. impressionisme; Ital. impressionismo. A school or tendency of art, in which the aim is to record or render the immediate and personal impressions received or felt by the artist.

The impression may be derived from an outer scene, or from inner experience. The media concerned are chiefly those of painting, music, and literature. In painting, the term has meant more definitely the effort to portray the momentary effect produced by some aspect of nature, seen at once and as a whole, without details, but with no alteration of colour. An especially prominent phase of impressionist painting has been the rendering of the effects of light, notably of sunlight or plein air.

In contrast with IDEALISM (q.v.) in art, which emphasizes meaning or EXPRESSION (q.v.), impressionism requires that the artist should abstract himself from memory, seeing only that which he looks upon, and that as for the first time.

It is distinguished from certain other phases of REALISM (q.v.) and NATURALISM (q.v.) in art, in that its aim is to present not a literal transcript of nature, but the impression or emotion which nature gives to the artist. It is opposed also to formalism (see FORM, in aesthetics). This shows itself in painting and drawing by emphasizing 'values,' or light and shade effects in mass, rather than accurate delineation, and in music by the presentation of a series of tone-colour effects instead of the development of a theme. In literature, impressionism aims to tell its story by a series of vivid pictures, and in criticism to record the critic's impression as immediately felt, with no attempt at analysis or objective evaluation.

The term came into use in connection with the paintings of E. Manet and others, which were exhibited in Paris in the seventies. Although disowned by the school itself, which preferred to be known as that of the 'Independents,' it has passed into general use and has been extended to other arts. It is useful to indicate an aspect of the work of many artists who are not impressionists in a narrow sense. Such, among painters, were Corot and Millet; among writers, Sterne and Keats; among musicians, Wagner and Grieg.

Literature: MUTHER, Hist. of Mod. Painting, ii. chap. xxxiii; LECOMTE, L'Art Impressioniste (1892); DURANTY, La nouvelle peinture (1876); DURET, Les peintres impressionnistes (1879); HUYSMANS, L'Art moderne (1892); WEDMORE, in Fortn. Rev., Jan., 1883, T. CHILD, Art and Criticism (1892), 70 ff., 162 ff.; The Desire of Beauty (1892), chap. ix; Art J., xlv. 28, 103; Quart. Rev., clxxxv. 173; Blackwood's Mag., c1xiii. 630; FRANCIS BATE, The Naturalistic School of Painting (2nd ed., 1887). (J.H.T.)

Impulse [Lat. impulsus, from impellere, to impel]: Ger. Trieb; Fr. impulsion; Ital. impulso. A conation in so far as it operates through its intrinsic strength, independently of the general system of mental life. Action on impulse is contrasted with action due to deliberation. As a typical instance of impulse we may refer to the motor tendencies connected with a FIXED IDEA (q.v.) See also the next topic.

In the experience which has been called the 'fascination of a precipice,' the idea of throwing oneself over the edge into the depths below acquires an insistent vivacity, which may lead to its realization, though the whole organized system of our mental life is up in arms to resist it. Animal cravings, such as that for drink or opium, may operate in a similar way. In general the activity of the lower animals is impulsive; for in them conative tendencies do not seem to be co-ordinated and subordinated in an organized system of motives. The mental processes of the lower animals are mainly of the perceptual type. But when conscious life is mainly perceptual, the several trains of activity which compose it are relatively disconnected with each other. Each arises out of the circumstances of the present moment, instead of being part of a general plan of life. On the other hand, in the deliberate action peculiarly characteristic of human beings, the impulse arising from the circumstances of the present is brought into relation with a general system of ends, and is repressed, strengthened, or modified accordingly.

It will be seen that impulsiveness is a relative conception. Any conation may be regarded as having a certain strength of its own, and also in other circumstances as forming part of a mental system.

A special case of impulse is the so-called INSTINCT-FEELING (q.v.), the conation of rising strength, before its expenditure in an instinctive action. The term is useful as marking off this class of impulses, and so preventing the use of the term INSTINCT (q.v.) for impulse.

The use of the word as a technical term is modern. There is a confusing variety of definitions. 'A conation initiated and fused with a feeling of craving, in view of some object of sense-perception or imagination, with a tendency to discharge in a complicated form of purposeful movements' (Ladd, Psychol. Descrip. and Explan., 592). 'An emotional state which tends to express itself in external movements of the body of such a character that their result is the increase of a pre-existing pleasure or the removal of a pre-existing pain. Consciousness of the result previous to its occurrence is not implied' (Wundt, Grundzüge d. physiol. Psychol., ii. 410). Our definition attempts to give the common element in the varying usages. It is also in accordance with popular usage.

Literature: see the textbooks of psychology; also BIBLIOG. G, 2, s. (G.F.S.- J.M.B.)

Impulse (abnormal). An abnormal impulse appears in mental disorders as an impairment of the will, owing to which the transition from thought to action is too sudden and too little controlled. An uncontrollable impulse is thus a state of defective inhibition, which is often a characteristic factor in mania, in excited melancholia, and in the first stage of general PARALYSIS (q.v.).

Clouston and others speak of certain cases in which this is the dominant symptom, as impulsive insanity. Homicidal and suicidal impulse, destructive impulses, the unconscious acts of an epileptic are types of pathological impulses. It is customary also to include under impulse the feeling of a marked tendency towards an action even when control takes place. The morbid impulse which many normal persons feel to throw themselves from a height or to commit some glaring impropriety are of this type. In many such cases the intellectual aspect is more prominent, and they become akin to cases of PHOBIA (q.v.) and MANIA (q.v.). Such an impulse also resembles the IMPERATIVE IDEA (q.v.). (J.J.)

Imputation (in law) [Lat. imputare, to impute]: Ger. Zurechnung; Fr. imputation; Ital. imputazione. The attribution to a particular person of legal responsibility for an act; it is properly used only of free actions and their natural consequences (see Wolff's Inst., chap. i. § 3).

Imputation is also used by civilians to signify an appropriation of payments where there are several debts and enough is not paid to satisfy all. (S.E.B.)

Imputation (in theology). The doctrine (1) of the attribution of the guilt of Adam's sin to his posterity; (2) of the attribution of the merit of Christ's righteousness to believers.

It is generally agreed that imputation is a forensic term, and that the transfer of guilt and merit is to be understood legally and not morally. The attempt to rationalize the putative act has developed great divergences of view, ranging from extreme Augustinianism on the one hand to Pelagianism on the other. On the question of the imputation of Christ's righteousness, if we leave out of view the moral theory of the Atonement as practically denying imputation, there is substantial agreement that the transfer rests on a substitutionary act of free grace on the part of Christ.

Literature: SCHAFF, Creeds of Christendom; FISHER, Imputation; DORNER, Gesch. d. Protestantischen Theol., ii; EDWARDS, The Great Doctrine of Original Sin; STEVENS, The Pauline Theol.; C. HODGE, Bib. Repertory, July, 1830, 1831; October, 1839. (A.T.O.)

In and for itself: see HEGEL'S TERMINOLOGY, Glossary, 'An und für Sich,' and 'An Sich,' and KANT'S TERMINOLOGY, Glossary, 'Ding an Sich.'

In esse, in intellectu, in re [Lat.]. Expressions denoting different forms of REALITY AND EXISTENCE (q.v.). See also LATIN AND SCHOLASTIC TERMINOLOGY 'Esse,' and 'Realitas.' (J.M.B.)


Inability (in theology) [Lat. in + habilis, manageable]: Ger. Unzulänglichkeit; Fr. incapacité (?); Ital. inabilità. The want of power to do the will or to obey the law of God, this want of power being either natural, arising from the lack of capacity, or moral, arising from the absence of disposition.

Man's inability is ordinarily regarded as an effect of the Fall. In early Christian thought the opposite poles are found in Pelagianism, which denies inability, and Augustinianism, which asserts it in a radical sense. In mediaeval theology the doctrine of Aquinas is representative, who affirms man's moral power to will and desire the good, but denies his ability to realize it without divine help. In modern theology a less radical difference separates Calvinism from Arminianism. Among Calvinists the old school adheres to the doctrine of Augustine, while the new school denies natural inability and asserts that man could do good if he would. Arminianism differs from old-school Calvinism in asserting gracious ability; that is, man's power to co-operate with divine grace in his own salvation.

Literature: C. HODGE, System. Theol., ii. 257-77; HODGSON, New Divinity examined, Brit. Quart. Rev., July, 1867; New Englander (1868), 486-90, 496-9, 511, 553. (A.T.O.)

Inattention [Lat. inattentio]: Ger. Unaufmerksamkeit; Fr. inattention; Ital. disattenzione. A relative term denoting more or less absence of attention to a particular object when attention is normally possible. It includes the more restricted terms ABSTRACTION, DISTRACTION, and ABSENT-MINDEDNESS. (J.M.B., G.F.S.)

Incantation: see MAGIC.

Incapacity [Lat. in + capacitas, ability to contain]: Ger. Dispositionsunfähigkeit; Fr. incapacité; Ital. incapacità. Inability arising from mental disease.

It raises an important practical question, especially in relation to legal or testamentary rights. Technically, the question is one which the laws and courts decide; and while a considerable change of opinion has taken place in recent years, and some attempt has been made to reconcile legal practice with medical views, the question of incapacity must always be somewhat arbitrarily decided. The question is not so broad as that of general responsibility for one's action; but in both cases a knowledge of the distinction between right and wrong, an appreciation of the probable consequences of one's action, and an ability to resist undue influence on the part of others are usually regarded as the most essential requisites. The absence of these powers would be regarded as an indication of incapacity.

Literature: MAUDSLEY, Responsibility in Mental Disease (1874); CLEVENGER, Med. Jurisprudence, ii. (1898); DELBRÜCK, Gerichtl. Psycho-Pathol. (1897). (J.J.)

Incarnation [Lat. in + caro, flesh]: Ger. Fleisch- (or Mensch-) werdung; Fr. incarnation; Ital. incarnazione. The assumption by Deity of mortal (generally human) form. In Christian theology, the doctrine of the union of divine and human nature in the person of Jesus Christ. Cf. SPIRITISM.

The belief that the gods assume mortal form is imbedded in the religious traditions of most nations. Whether or not some form of this belief is essential to religion, it is certainly true that in precisely those religions that are most spiritual does it hold the most prominent and central place. The Christian conception of the Incarnation has tended to vary according as the greater emphasis has been placed on the humanity or the Divinity of Christ, but all Christian creeds agree in affirming that in him the Divine Word has somehow become flesh.

Literature: DORNER, Hist. of the Doctrine of Christ, &c. (Ger. and Eng.); B. F. WESTCOTT, The Incarnation and Our Common Life, 7 (1894); textbooks of systematic theology. (A.T.O.)

Incipient: see NASCENT.

Inclination [Lat. inclinatio]: Ger. Neigung; Fr. inclination, penchant; Ital. inclinazione, tendenza. (1) Used loosely in the general sense of APPETENCE (q.v.). (2) A disposition to act on considerations of personal ease or pleasure. In this sense, inclination is often contrasted with duty. (J.M.B.- G.F.S.)

Inclusion (in logic): see SUBORDINATION.

Incoherence [Lat. in + cohaerens, sticking together]: Ger. Incohärenz, Verwirrtheit; Fr. incohérence; Ital. incoerenza. Want of orderly connection in thought and speech; it thus implies an abeyance of the voluntary selecting and co-ordinating processes of the intelligence, and a consequent exposure of the train of ideas to the caprices of the imagination or to accidental association.

Incoherence thus becomes characteristic and somewhat permanently so, of certain types of mania and of dementia; it appears as a transitory state in the delirium of disease, in the effect of psychic poisons (see PSYCHIC EFFECTS OF DRUGS), in dreaming, &c. It is important psychologically as showing that consistent, rational thought is a selective process controlled by the highest cortical centres, while the several factors and materials of such thought may be present in a less developed process controlled by a lower range or level of centres. (J.J.)

Income: see EARNINGS.

Incompatible: Not COMPATIBLE (q.v.).

Incomprehensible: see COMPREHENSION; and for relation to inconceivable and UNKNOWABLE see the latter topic.

Inconceivable and Inconceivability: see UNKNOWABLE, and TESTS OF TRUTH.

Inconceivableness (of the contrary): see UNIVERSAL POSTULATE.

Inconsistency [Lat. in + con + sistere, to stand]: Ger. Unvereinbarkeit; Fr. inconsistance; Ital. incompatibilità. The relation between two assertions which cannot be true at once, though it may not be a direct contradiction; as between a statement of items and a statement of their total. Cf. CONSISTENCY.

A logical discrepancy, on the other hand, is a difference between two statements either difficult or impossible to reconcile with the credibility of both. It is said to be negative if one assertion omits an inseparable part of the fact stated in another; as when one witness testifies that A pointed a pistol at B, and another that A shot at B. It is positive if one asserts what the other denies. But even then it may often be conciliable (verträglich); that is, may not prove that either statement is in other respects untrustworthy. See Bachmann, Logik, §§ 214 ff.

'Inconsistent' is applied to an assertion, or hypothesis, which either in itself, or in copulation with another proposition with which it is said to be inconsistent, might be known to be false by a man devoid of all information except the meanings of the words used and their syntax.

Inconsistent differs from contradictory (see CONTRADICTION) in being restricted usually to propositions, expressed or implied, and also in not implying that the falsity arises from a relation of negation. 'That is John' and 'It is Paul' are inconsistent, but hardly contradictory. Moreover, contradictory is also used in a peculiar sense in formal logic. Cf. OPPOSITION. (C.S.P.)

Inco-ordination [Lat. in + co-, together, + ordinare, to arrange]: Ger. Unkoordiniertheit (Ataxie); Fr. incoordination (ataxie); Ital. incoordinazione. Lack of ability or defective ability to control movements and to combine them into orderly, useful, and purposive actions. See ATAXIA. (J.J.)

Increasing Return: Ger. steigende Produktivität; Fr. loi des débouchés; Ital. prodotto crescente. The converse of DIMINISHING RETURN (q.v.).

The increasing profit when we enlarge the output of a factory is often contrasted with the diminishing profit when we attempt to do the same thing on a farm; and some writers say that the factory is subject to a law of increasing return which contrasts with the law of diminishing return that prevails in agriculture. We quote two different but not conflicting views of the subject from Marshall's Principles of Economics and from Hadley's Economics.

'An increase of capital and labour leads generally to an improved organization; and therefore in those industries which are not engaged in raising raw produce it generally gives a return increased more than in proportion; and further, this improved organization tends to diminish or even override any increased resistance which nature may offer to raising increased amounts of raw produce. If the actions of the laws of increasing and diminishing returns are balanced, we have the law of constant return, and an increased produce is obtained by labour and sacrifice just in proportion' (Marshall).

'With a given amount of fixed capital, whether invested in agriculture or in manufactures, any increase of output diminishes the charges on such capital per unit of product. The current expenses per unit of product do not thus tend to diminish, but rather to increase. Whether with an increase of output the gain from fuller use of fixed capital outweighs the loss from increased current expenses, depends chiefly on the degree to which the fixed capital was previously utilized. If it was not fully utilized, we shall see the phenomena of increasing return; if it was already fully utilized, we shall see those of diminishing return. The apparent contrast between agriculture and manufactures in this respect is chiefly due to the fact that population habitually approaches a limit set by the arts of food production, so that its agricultural improvements are always employed nearly to the limit of profitable output; while in manufactures there is no such necessary increase of demand, and fixed capital is often quite inadequately employed' (Hadley). (A.T.H.)

Increment [Lat. incrementum, increase]: Ger. (1) Zunahme; Fr. (1) incrément; Ital. incremento, aumento. (1) In psychophysics: relative increase in amount of stimulation. It is expressed as a fractional part of the stimulation existing before the increase is made.

(2) In mathematics: equivalent to an INFINITESIMAL (q.v.) increase. (J.M.B.)

Indefinite: see INFINITE (notion of, ad fin.), QUANTITY (in logic), and DETERMINATE (in biology).

Indemnity (in law) [Lat. indemnis, from in + damnum, hurt]: Ger. Entschädigung. Indemnität; Fr. indemnité; Ital. indennità. (1) What is given by or due from one in behalf of whom another acts, to make the latter good for any consequent loss. An obligation to indemnify is implied in favour of agents and sureties. Indemnity against mere liability to loss can be claimed only under an express contract.

(2) Compensation for losses or expenses for which the party making it is or agrees to be held responsible, as e.g. a war indemnity.

Act of Indemnity: a statute or sovereign decree absolving from its penalties certain persons or classes of persons who have transgressed the law. (S.E.B.)

Independence [Lat. in + de + pendere, to hang]: Ger. Unabhängigkeit; Fr. indépendance; Ital. indipendenza. (1) Two subjects are independent in so far as the possession of any character by the one does not require nor prevent the possession of any character by the other, unless these characters are directly or indirectly relative to the other individual.

(2) Two events are independent if either is equally probable whether the other takes place or not. (C.S.P.)

(3) See FREEDOM (political).

Indeterminism [Lat. indeterminatio]: Ger. Indeterminismus; Fr. indéterminisme; Ital. indeterminismo. (1) The theory according to which mental change or development cannot in all cases be fully accounted for by pre-existing psychological or external conditions. Cf. DETERMINATION (mental). (G.F.S.- J.M.B.)

(2) The extreme form of free-will theory. It represents volition as, to some extent or in certain circumstances, independent of the strength of motives, or as itself determining which motive shall be the strongest. See FREEDOM, and WILL.

The term indeterminism (2) is given to mark the opposition to the theory of the complete causal connectedness of motive and volition, commonly called DETERMINISM (q.v.). It describes best what is called 'liberty of indifference,' and is defined by Windelband (Hist. of Philos., II. i. 16, 194, Eng. trans.) as 'a choice between different possibilities that is determined by no causes.' But upholders of free will usually deny that their theory can be correctly described as indeterminism. Thus Kant (Relig. Erstes Stück, sub fin.; Werke, ed. Hartenstein, vi. 144 n., Abbott's trans., 359 n.) says: 'Freedom does not consist in the contingency of the action (that it is not determined by reasons at all), that is, not in indeterminism (that it must be equally possible for God to do good or evil, if his action is to be called free), but in absolute spontaneity.' Calderwood (Handb. of Mor. Philos., 182, 10th ed.) says: 'In the history of philosophy there are no thinkers to be classified under the latter designation [indeterminists].' The term is, however, used by W. James to describe his own view (accepted on extra-psychological grounds) that the causal connection of psychical phenomena is not complete, and leaves room for an undetermined choice of will (Princ. of Psychol., ii. 573); and he further allows that this theory of 'indeterminism is rightly described as meaning chance' (Will to Believe, 159). (W.R.S.)

Index (in craniometry) [Lat. index, from indicare, to point out]: Ger. Index; Fr. indice; Ital. indice. The relation of two dimensions of the skull to one another.

The most important index is the cephalic, which (if one neglects detailed differences in the mode of measurement) may be described by the formula:

Maximum transverse diameter X 100.
Maximum antero-posterior diameter
Long-headed skulls in which this index is 75 and under are called dolichocephalic; those with an index of 77.78 to 80.00 are mesaticephalic; index 80.01 to 83.33, sub-brachycephalic; index 83.34 and above, brachycephalic (Broca). Roughly speaking, the index 80:100 is that of a medium skull (mesocephalic), while the index 75:100 is quite a long skull (dolicho-) and the index 85:100 quite a short skull (brachy-) (for variations in these terms, &c., see references cited under CRANIOMETRY). Of other indices the following may be mentioned as most frequently employed. The vertical index, or relation of maximum height to length of head (B, Bg to Gl, O, in the figure under CRANIOMETRY), varies from 69 to 78; the facial index, which is the ratio of the width of the face (horizontal distance between the two zygomatic arches) to the height of the face, and varies from 61 to 73 (see also FACIAL ANGLE); the nasal index, or proportion of length to width of nose, from below 48:100 to above 53:100; orbital index, or ratio of height to width, from below 84:100 to above 89:100. If the breadth of the head is expressed in terms of the height, we should have a transverse vertical index (86:104), and so on.

Literature: art. Indices, in Dict. d'Anthropol.; MANOUVRIER, Année Psychol., v. (1899) 558 (a review of recent work); the references under CRANIOMETRY. Cf. also BRAIN, IV. (J.J.)

Index (in exact logic). A sign, or representation, which refers to its object not so much because of any similarity or analogy with it, nor because it is associated with general characters which that object happens to possess, as because it is in dynamical (including spatial) connection both with the individual object, on the one hand, and with the senses or memory of the person for whom it serves as a sign, on the other hand.

No matter of fact can be stated without the use of some sign serving as an index. If A says to B, 'There is a fire,' B will ask, 'Where?' Thereupon A is forced to resort to an index, even if he only means somewhere in the real universe, past and future. Otherwise, he has only said that there is such an idea as fire, which would give no information, since unless it were known already, the word 'fire' would be unintelligible. If A points his finger to the fire, his finger is dynamically connected with the fire, as much as if a self-acting fire-alarm had directly turned it in that direction; while it also forces the eyes of B to turn that way, his attention to be riveted upon it, and his understanding to recognize that his question is answered. If A's reply is, 'Within a thousand yards of here,' the word 'here' is an index; for it has precisely the same force as if he had pointed energetically to the ground between him and B. Moreover, the word 'yard,' though it stands for an object of a general class, is indirectly indexical, since the yard-sticks themselves are signs of the Parliamentary Standard, and that, not because they have similar qualities, for all the pertinent properties of a small bar are, as far as we can perceive, the same as those of a large one, but because each of them has been, actually or virtually, carried to the prototype and subjected to certain dynamical operations, while the associational compulsion calls up in our minds, when we see one of them, various experiences, and brings us to regard them as related to something fixed in length, though we may not have reflected that that standard is a material bar. The above considerations might lead the reader to suppose that indices have exclusive reference to objects of experience, and that there would be no use for them in pure mathematics, dealing, as it does, with ideal creations, without regard to whether they are anywhere realized or not. But the imaginary constructions of the mathematician, and even dreams, so far approximate to reality as to have a certain degree of fixity, in consequence of which they can be recognized and identified as individuals. In short, there is a degenerate form of observation which is directed to the creations of our own minds -- using the word observation in its full sense as implying some degree of fixity and quasi-reality in the object to which it endeavours to conform. Accordingly, we find that indices are absolutely indispensable in mathematics; and until the truth was comprehended, all efforts to reduce to rule the logic of triadic and higher relations failed; while as soon as it was once grasped the problem was solved. The ordinary letters of algebra that present no peculiarities are indices. So also are the letters A, B, C, &c., attached to a geometrical figure. Lawyers and others who have to state a complicated affair with precision have recourse to letters to distinguish individuals. Letters so used are merely improved relative pronouns. Thus, while demonstrative and personal pronouns are, as ordinarily used, 'genuine indices,' relative pronouns are 'degenerate indices'; for though they may, accidentally and indirectly, refer to existing things, they directly refer, and need only refer, to the images in the mind which previous words have created.

Indices may be distinguished from other signs, or representations, by three characteristic marks: first, that they have no significant resemblance to their objects; second, that they refer to individuals, single units, single collections of units, or single continua; third, that they direct the attention to their objects by blind compulsion. But it would be difficult, if not impossible, to instance an absolutely pure index, or to find any sign absolutely devoid of the indexical quality. Psychologically, the action of indices depends upon association by contiguity, and not upon association by resemblance or upon intellectual operations. See Peirce, in Proc. Amer. Acad. Arts and Sci., vii. 294 (May 14, 1867). (C.S.P.)

Index Number: Ger. Indexzahl; Fr. (Eng. term in use); Ital. numero-indice. A figure calculated to show the relative level of prices in a certain year as compared with that in preceding years, so that we may know whether prices in general have risen or fallen.

The index numbers of The Economist, which were the first calculated, consisted of simple additions of prices of a number of articles for successive years. An improvement was made when these numbers were reduced to a percentage basis, some one year which is taken as the basis of comparison being given the index number 100. A still further improvement was made by taking, instead of an arithmetical average of prices, a 'weighted' average of prices, which considers the relative amounts of the different articles used in trade or consumption.

Literature: principally in the economic journals. The chief authorities on the subject are SAUERBECK and LOETBRER. (A.T.H.)

India (philosophy and religion in): see ORIENTAL PHILOSOPHY (India).

Indictment [Med. Lat. indictare, to declare]: Ger. Anklage; Fr. accusation, jugement (to indict, mettre quelqu'un en jugement), Ital. accusa. (1) A formal charge of crime.

(2) In English and American law: a written charge of crime or misdemeanour, presented to a court for prosecution, by a grand jury. It is drawn up by the prosecuting officer, and at that stage is termed a bill of indictment. If the grand jury are satisfied that there is probable cause for supporting it, their foreman indorses it as 'a true bill,' and returns it to court, whereupon it becomes an indictment. The partly accused is then entitled to trial before a petit jury.

The grand jury is an English institution for the protection of the individual against unjust prosecution. In cases of grave crimes most American constitutions require the return of an indictment before the accused can be brought to trial. (S.E.B.)

Indifference [Lat. in + differens, different]: Ger. Gleichgültigkeit; Fr. sentiment d'indifférence; Ital. indifferenza. (1) The state of mind in which a mental object, although noticed or thought of, fails to excite further interest for its own sake.

The state of indifference is ascribed to the subject, and the adjective indifferent is applied both to the agent and to the object or thought. The indifference thus defined may refer to mere intellectual interest, to interest leading to voluntary determination, or to the determination of a moral attitude (see the next topic).

(2) Emotional neutrality or lack of excitement or of affection of any sort. For this the term neutral is to be preferred. Cf. INDIFFERENCE POINT. (J.M.B.- G.F.S.)

Indifference (moral). That which is outside the application of moral law, and without tendency to promote or retard moral ends, is said to be morally indifferent and to have the quality of moral indifference.

Actions neither required nor forbidden by the moral law, or which do not affect morality, are called morally indifferent. The doctrine of 'things indifferent' (adiafora) arose in the Stoic school. Owing to the abrupt opposition of 'good' and 'bad,' a large class of objects were at first regarded as indifferent. But within this class, three sub-classes came to be distinguished: things to be preferred because they helped the life according to nature; things to be avoided because they hindered it; and things indifferent in the narrower sense. The conception of things indifferent is, according to Kant, extra-moral.

Literature: CICERO, Acad., ii., De Fin. iii. 15, 16; ZELLER, Philos. d. Griechen, III. i. 259 ff. (3rd ed.); KANT, Relig., Erstes Stück (Werke, ed. Hartenstein, vi. 116); ABBOTT, Kant's Theory of Ethics, 329 (3rd ed.). (W.R.S.)

Indifference (in philosophy). (1) The principle of adiafora, common to the Stoics, Cynics, and Sceptics of Greece, that all is indifferent save virtue and vice, which alone have absolute value. See SCHOOLS OF GREECE (Cynics), STOICISM, and SKEPTICISM; cf. also RELATIVITY OF KNOWLEDGE.

(2) The view of certain scholastics (e.g. Adelard of Bath) that a thing is indifferently an individual or a universal according to the point of view. (J.M.B.)

Indifference Point: Ger. Indifferenzpunkt, Nullpunkt; Fr. point d'indifférence; Ital. punto d'indifferenza. The theoretical zero or point of transition on a scale of positive and negative values; applied in psychology to the theoretical point at which neither of two contrasted sense or other qualities, which are supposed to depend on the same sort of stimulation, is experienced: as the indifference point on the scale of temperature, of hedonic tone, &c.

The indifference point as thus defined is with the threshold, much discussed; many holding that both are merely conceptions convenient for the purposes of graphic representation, and in no sense psychological values. On this view, the indifference point of temperature is simply no temperature sensation, not a point on a scale of real sensation values; and the attempt to establish thresholds for positive heat-values and positive cold-values itself shows this: for the part of the curve between the two thresholds would be a distance, not a point, and we should have two sensation curves, one for each quality, not at all connected with each other. This is emphasized by the relative character of the THRESHOLD (q.v.). (J.M.B., G.F.S.)

Indirect (in logic): see PROOF, REASONING (inference), and SYLLOGISM.

Indirect Selection: see ORGANIC (or INDIRECT) SELECTION.

Indirect Vision: Ger. indirektes Sehen; Fr. vision indirecte; Ital. visione indiretta. Visual perception of objects when the regard is directed to something else. (J.M.B.)

Indirect vision takes place with the peripheral portions of the retina. It differs from central vision in three ways: (1) the power of space discrimination of the retina falls off rapidly outside of the fovea -- more rapidly above and below than in a horizontal direction; (2) after the eye has suffered adaptation (regeneration of the visual purple), all lights, except those near either end of the spectrum, appear surprisingly brighter when indirectly viewed than when their images fall upon or near the fovea; (3) the colour sensitiveness of the retina alters from the centre outwards. The innermost or paracentral zone is entirely sensitive to colour; then follows a zone of red-green blindness; the outermost zone is wholly colour-blind. Cf. Sanford, Course in Exper. Psychol., expts. 117 b, 136, 137, 161.

Early experiments on peripheral colour vision were made by Clerk Maxwell and Woinow in 1870. Hess' results (Arch. f. Ophthal., XXXV. iv. 1 ff., 1899) show that the red and green which do not change colour before becoming invisible, in the middle zone, are Hering's fundamental red and green. V. Kries has recently found that the distribution of brightness in the spectrum of the outermost zone, with bright adaptation, is that of the normal spectrum (Zeitsch. f. Psychol., xv, 1897, 247). The fact, as it stands, is thought to tell against Hering's theory. Cf. PURKINJE PHENOMENON, and VISION. (E.B.T.- C.L.F.)

Literature: on the general topic, EXNER, Arch. f. Ophthal., xxxii. 1, 233 ff. (1886); A. E. FICK, Pflüger's Arch., xliii. 441 ff. (1888); KRISCHMANN, Philos. Stud., v. 447 ff. (1889), viii. 592 ff. (189); HERING, Arch. f. Ophthal., xxxv. 4, 63 ff. (1889), xxxvi. 1, 264 (1890); Pflüger's Arch., xlvii. 417 ff. (1890); A. PICK, Pflüger's Arch., xlvii. 274 ff. (1890); Hermann's Handb. d. Physiol., iii. 1, 206 ff.; AUBERT, Physiol. Optik, 495, 539 ff., 585 ff.; Physiol. d. Netzhaut, 89 ff., 116 ff.; HELMHOLTZ, Physiol. Optik (2nd ed.), 255 ff., 268, 372 ff.; HOLDEN, Arch. f. Ophthal., xxiii. 40 ff.; v. KRIES, Zeitsch. f. Psychol., ix 81 ff.; Arch. f. Ophthal., xlii. 3, 95 ff.; Zeitsch. f. Psychol., xv. 247 ff.; LUCKEY, Amer. J. of Psychol., vi. 489 ff.; GUILLERY, Zeitsch. f. Psychol., xii. 243 ff.; WILLIAMS, J. of Amer. Med. Assoc. (1898), xxxi. 767; HELLPACH, Philos. Stud., xv. 524 ff. For illusions of form in indirect vision see SANFORD, Course in Exper. Psychol., expt. 172; for the indirect perception of movement, ibid., expt. 224. (E.B.T.- C.L.F.)

Indiscernibles (principle of sameness of) [Lat. indiscernibilis, indistinguishable]: Ger. Ununterschiedbaren; Fr. indiscernables; Ital. indiscernibili. Leibnitz maintained this principle, i.e. that no two monads -- in general, no two things in the universe -- are exactly alike, else they would be not two, but one (Monadologie, 9; Nouveaux Essais, ii. 27, 1-3).

This principium identitatis indiscernibilium was a characteristic element of the Leibnitzian view of the world (Falckenberg, Hist. of Mod. Philos., 278-80). Similar views have been held by other thinkers, ancient and modern (the Stoics, Ueberweg, Hist. of Philos., i. 196; Giordano Bruno). See LIKENESS, and DIFFERENCE; and cf. INDIVIDUAL. (A.C.A.Jr.)

Individual [Lat. individuus, undivided]: Ger. (1, 3) einzeln (Wesen, &c.), (2, 4) individuell (adj.), Individuum (n.); Fr. individuel (adj.), individu (n.). Ital. individuale (adj.), individuo (n.). (1) A single being, as distinct either from a collection of beings or from the logical object of the general concept; a unique being; a being at least numerically distinct from all other beings. (2) A being that cannot be divided into parts to which the name of this being will apply. Thus a general name applies to a class of objects which can be divided into classes, to any one of which the class-name can still be applied, as Frenchmen, Germans, or Russians are all equally Europeans. But the name of an individual being, as for instance Socrates, cannot be applied to any of the parts, such as the hand or foot, into which Socrates can be divided. (3) An independent, separable being, capable of existing alone. (4) In ethics a person, an individual as opposed to a corporation or a collection of men, or to a social group or organization of any kind.

The concept of the individual is at once one of the most familiar and the most difficult both in the world of common sense and in the world of philosophy. That the beings which are to be found in the world, whether inanimate objects or living beings, whether material or mental, are individuals, i.e. are distinct, singular, and unique, is a matter of common belief and report. But what constitutes individuality, or what is the principle of individuation, has been a matter of controversy both within the realm of special science and from the point of view of logical and metaphysical definition.

In logic the individual is opposed to the various kinds of universal concepts and classes, as, for example, to genus or species, or property, or accident. In psychology it has been frequently asserted that individual objects are the immediate objects of our perceptive experience; so that it has been frequently maintained, as sufficiently defining the nature of an individual being, that an individual is any object perceived by the mind as an external or as a real object. From this point of view the idea of individuality as character of beings is derived directly from experience, and is irreducible to simpler ideas. As against this view, it has been maintained that the direct object of our perceptual experience is always a series or complex of definable or indefinable qualities, characters, relations, and behaviours of objects. Thus we observe that an orange is coloured, is round, is of a given weight, is in given relations to other observed objects, as for instance lying on a plate. But to observe these characters, however great their number and complexity, is still to observe characters that might be shared by other oranges, and frequently by other objects, so that it seems as if the individuality of the object were precisely what we least directly perceive. In case of individual persons, it is plain that we mean by personal identity a character which could never be made the object of any simple perceptive act; and in general the concept of individual being, in the various special sciences, as well as in metaphysical inquiry, shows many characters that cannot be derived from mere perception in any case. It is somewhat easier to regard the idea of individuality as an ultimate and indefinable idea, without giving any ground whatever, in experiences or in articulate thought, for our overwhelming assurance that the objects with which we deal are individuals. Nevertheless, this way of treating the problem would be merely an abandonment of the question as insoluble; and accordingly we find in the history of thought a considerable number of efforts to define what has been called the principle of individuation. Such efforts have also played a part in the definitions of the individual that have been framed to meet the exigencies at various special times.

The problem of the nature of individuality is first reached in European philosophy as the result of those efforts at the definition of the logical method which assume definite form in the Socratic, Platonic, and Aristotelian doctrines. The Platonic ideas were beings supposed expressly to correspond to our general conceptions. A discussion of the nature of these ideas, and of their relations to one another and to the world of facts, of sense, and of ordinary experience, made prominent the question: What is meant by an individual? The problem in question is very explicit in the mind of Aristotle, though it cannot be said that he gave any very explicit solution of the questions that he himself raised. According to Aristotle, all beings in the universe are individuals, and universals have being only as realized in individual entities. On the other hand, science, according to Aristotle, is necessarily concerned with the universal, that is, with the laws and the ideal general characters possessed by facts. And yet, according to Aristotle, science undertakes to know being. Thus arises the familiar paradox of the Aristotelian system, that just that character of facts which science best knows is not that character which constitutes the true being of anything, since this true being is individual, and what science knows is universal. As to the principle of individuation, Aristotle is not explicit, except in the case where he is speaking of obviously corporeal entities, when he upon occasion says that their material aspect is that which constitutes the individuality of any one being; while what he calls the form or general nature is common to many individuals.

The problem of the definition of the individual became prominent in the philosophy of the Christian Church in the Middle Ages, especially owing to the importance which ethical individuality had acquired in Christian doctrine, and in consequence of the relation of individuality to the doctrine of the Trinity. In the early ages of scholastic philosophy, the discussion regarding the nature of universals was especially prominent, while from the age of Thomas Aquinas onwards, scholastic philosophy made especially important the principle of individuation and the nature of individuality. Here it was a classic Thomistic doctrine that, in the realm of nature, matter is the individuating principle, so that the purely incorporeal entities, such as the angels, could be individuated only by their form, and so that consequently, as the well-known Thomistic theory maintained, two angels of the same species do not exist. The ethical individuals in the human world, according to Thomas, are genuine individuals, but they are individuated primarily by the different bodies to which the souls belong, so that when absent from the body, the soul, between death and the judgment, would be individuated by reason of what Thomas calls its inclinatio to a particular corporeal embodiment, an inclinatio which at the resurrection would be met by the presence of the glorified body of the saved or of the equally permanent material organization of the lost. To the Thomistic theory, Duns Scotus opposed the doctrine that a special form, called by him the haecceitas, is responsible for the individuation of every being, corporeal or incorporeal. This haecceitas, different in each individual, is something that is said to be 'fused with the common nature,' in such wise that the doctrine of Duns Scotus especially lays stress upon the fact that the difference between individual beings is a real and ultimate, non-corporeal, but not necessarily indescribable, character of each being -- a character which a higher type of intelligence than our own may be able to appreciate, although it is admitted by Duns Scotus that this character is indefinable for our own human intellect.

In the philosophy of Leibnitz an effort is made to solve the problem of the individual by the famous principle of the identity of indiscernibles. According to this principle it is impossible that two individuals in the universe could be precisely alike. And the unlikeness between individuals is always of an essentially describable or intelligible character. Were two individuals in all respects precisely alike, so that whatever was predicated of one was true of the other, these two individuals would be ipso facto identical, and difference of individuality means difference of quality or character.

Post-Kantian thought, during the idealistic period, laid most stress upon the definition of the ego, or of the ethical and epistemological person, and dealt with the problem of individuality mainly in this case. New in this period of thought, therefore, especially after Kant's theory of the unity of self-consciousness, are the Fichtean and Schellingean attempts to define the relations between a finite individual and the absolute ego. New is also the Hegelian definition of the individual as 'the unity of the universal and the particular.' In other words, Hegel held that when a universal law or principle, of the type that he defined as the Begriff, gets a complete development and expression, in respect of all the particular or specific aspects which the nature of this Begriff involves, such total expression of a universal law is as such an individual being, so that the problem with regard to the individual becomes identical with the problem as to the way in which universal principles can find complete or wholly satisfying expression in nature or in mind, or in general in experience.

Since the close of the idealistic period the problem of the individual has received discussion especially from three points of view. In the first place, in modern psychology and epistemology, efforts have been made to deal afresh with the problems of the nature of individuality in its most general form. The most familiar of these efforts is one not wholly unknown to earlier thought, very plainly stated by Schopenhauer, and frequently developed in recent works -- an effort to make time and space the essential principles of individuation, to define the primary individual object as that which is in a given place, and at a given time, and to make the other forms of individuality derivable from this primary form of the idea by means of various associations between time and space, localization, and the various other characters possessed by moral or other types of individuals. The second point of view from which the problem has been discussed has been that of the biological sciences, and of the related branches of inquiry. Into these discussions this is not the place to go. The third point of view with regard to the individual has been that suggested by the ethical problem of the rights of the individual as a person, and of his relations to the social order. The revolt against certain eighteenth-century doctrines concerning the rights and position of the individual man has led to a number of forms of socialism and of ethical universalism, which have made light of the historical importance and of the moral value of the individual man. A frequent reaction against these very tendencies has led to reassertion of individualism, which has been associated with various more or less novel efforts to restate the definition of the ethical individual.

If we survey the problem of the individual apart from its history, it is easy to see that the question has several distinct forms, which may indeed be ultimately connected, but which are usually presented to our attention in quite different regions of inquiry. Amongst the sciences mathematics is prominent in dealing with individual objects and systems of individual objects, which as artificial creatures of definition, or as very simple abstractions from our experience of space, ought apparently to be topics of easy and final agreement. Yet regarding the nature of all these forms of mathematical individuality considerable difference of opinion has existed amongst mathematical experts. Examples of mathematical entities that appear more or less obviously as individuals are the unit in arithmetic, the point in geometry, the line, when regarded as an elementary concept in some forms of geometrical investigation, and several other cases of objects which are regarded as the elements of given mathematical systems. The question of the individuality, or at any rate of the singularity of such objects as space and time, viewed in their wholeness, has interested the mathematicians as well as the philosophers. In theoretical natural science, such concepts as the modern concept of energy, when compared with the usual concepts of matter, may well introduce the question whether recent theory is not really as much concerned with the problem whether universals exist, or whether individuals alone are real, as was ever scholastic doctrine. For energy as usually described appears to be an entity whose individuation is altogether problematic, and whose known character seems to be entirely of universal type. In the biological sciences the problem as to the living individual introduces entirely different questions and interests; and the problems of ethical individuality belong to still another realm of a decidedly special character. Finally, the problem of the ultimate place of the category of individuality in the world at large remains as an issue for general metaphysics. It is, nevertheless, a fair question for philosophical inquiry whether all these so various problems are not really much more closely connected than they seem, and whether a final definition which will hold for all forms of individuality may not yet be discovered. Cf. IDENTITY (individual).

Literature: the classic scholastic view of the problem is to be found in ST. THOMAS AQUINAS, Summa Theologica, P. 1, passim -- in particular, Q. xxx. art. iv; Q. xxix. arts. i, iii, and iv; Q. 1. art. iv; Q. lxxvi. art. ii. DUNS SCOTUS, in his commentary upon the Sentential, in the first half of the sixth volume of his collected works (London ed. of 1639), discusses the problem of individuality in connection with his Angelology. See, in particular, 374 ff., 403 ff., 487 ff. SUAREZ, in his Disputations metaphysicae, sums up the scholastic opinions on the whole range of the problem in Disp. v: De unitate individuali, eiusque principio. Father HARPER, in his Metaphysic of the School, i. 208-90, reviews the same issue at length. See also the youthful dissertation of LEIBNITZ, De principio Individuationis, and his later discussions of the problem, in particular in the Nouv. Ess., Lib. II. chap. xxvii. HEGEL treats our problem, in connection with the theory of universals, at the outset of the third part of his Logik. SCHOPENHAUER frequently, but always summarily, discusses the principle of individuation. For a collection of the passages in Schopenhauer see FRAUENSTADT, Schopenhauer Lexikon, i. 351. Amongst recent discussions that of SIGWART, Logik, Th. III. Abschn. II. § 78, may be mentioned. ROYCE has treated the topic at length in the Conception of God, 217-322, and in the World and the Individual; see also ORMOND, Foundations of Knowledge, Pt. II. chap. xii. (J.R.)

Individual (in biology): a single ORGANISM (q.v., in biology). (J.M.B.)

Individual (in logic) [as a technical term of logic, individuum first appears in Boethius, in a translation from Victorinus, no doubt of atomon, a word used by Plato (Sophistes, 229 D) for an indivisible species, and by Aristotle, often in the same sense, but occasionally for an individual. Of course the physical and mathematical sense of the word were earlier. Aristotle's usual term for individuals is ta kaq ekasta, Lat. singularia, Eng. singulars.] Used in logic in two closely connected senses. (1) According to the more formal of these an individual is an object (or term) not only actually determinate in respect to having or wanting each general character and not both having and wanting any, but is necessitated by its mode of being to be so determinate. See PARTICULAR (in logic).

This definition does not prevent two distinct individuals from being precisely similar, since they may be distinguished by their heceeities (or determinations not of a generalizable nature); so that Leibnitz' principle of indiscernibles is not involved in this definition. Although the principles of contradiction and excluded middle may be regarded as together constituting the definition of the relation expressed by 'not,' yet they also imply that whatever exists consists of individuals. This, however, does not seem to be an identical proposition or necessity of thought; for Kant's Law of Specification (Krit. d. reinen Vernunft, 1st ed., 656; 2nd ed., 684; but it is requisite to read the whole section to understand his meaning), which has been widely accepted, treats logical quantity as a continuum in Kant's sense, i.e. that every part of which is composed of parts. Though this law is only regulative, it is supposed to be demanded by reason, and its wide acceptance as so demanded is a strong argument in favour of the conceivability of a world without individuals in the sense of the definition now considered. Besides, since it is not in the nature of concepts adequately to define individuals, it would seem that a world from which they were eliminated would only be the more intelligible. A new discussion of the matter, on a level with modern mathematical thought and with exact logic, is a desideratum. A highly important contribution is contained in Schröder's Logik, iii, Vorles. 10. What Scotus says (Quaest. in Met., VII. 9, xiii and xv) is worth consideration.

(2) Another definition which avoids the above difficulties is that an individual is something which reacts. That is to say, it does react against some things, and is of such a nature that it might react, or have reacted, against my will.

This is the stoical definition of a reality; but since the Stoics were individualistic nominalists, this rather favours the satisfactoriness of the definition than otherwise. It may be objected that it is unintelligible; but in the sense in which this is true, it is a merit, since an individual is unintelligible in that sense. It is a brute fact that the moon exists, and all explanations suppose the existence of that same matter. That existence is unintelligible in the sense in which the definition is so. That is to say, a reaction may be experienced, but it cannot be conceived in its character of a reaction; for that element evaporates from every general idea. According to this definition, that which alone immediately presents itself as an individual is a reaction against the will. But everything whose identity consists in a continuity of reactions will be a single logical individual. Thus any portion of space, so far as it can be regarded as reacting, is for logic a single individual; its spatial extension is no objection. With this definition there is no difficulty about the truth that whatever exists is individual, since existence (not reality) and individuality are essentially the same thing; and whatever fulfils the present definition equally fulfils the former definition by virtue of the principles of contradiction and excluded middle, regarded as mere definitions of the relation expressed by 'not.' As for the principle of indiscernibles, if two individual things are exactly alike in all other respects, they must, according to this definition, differ in their spatial relations, since space is nothing but the intuitional presentation of the conditions of reaction, or of some of them. But there will be no logical hindrance to two things being exactly alike in all other respects; and if they are never so, that is a physical law, not a necessity of logic. This second definition, therefore, seems to be the preferable one. Cf. PARTICULAR (in logic). (C.S.P.)

Individual (social). (1) A single human being. (2) Hence, by development of the ideas of separateness and completeness, a human being in a marked degree differentiated from others: a centre of social influences.

The history of the concept individual is important both in psychology and in sociology. The individual has been conceived as independent of and antecedent to society, as correlative with society, and as dependent on and created by society. All of these conceptions are presented in Aristotle's Politics, where the distinctions are made that in genesis individual and society are inseparable, that in will and conduct the individual is independent or free, while in moral perfection he is created by the state. The political philosophy of Hobbes' De Corpore Politico assumes the antecedent completeness and sufficiency of the individual. Modern psychology and sociology demonstrate the interdependence of individual and society (cf. Baldwin, Social and Eth. Interpret.). See also INDIVIDUALISM. (F.H.G.)

Individual Psychology: Ger. Individual-psychologie; Fr. psychologie individuelle; Ital. psicologia individuale. That department of psychology which investigates the psychological individual considered as different from others, i.e. having for its subject-matter psychological variations among individuals.

Particular questions on which work has been done are: (1) the psychology of TEMPERAMENT (q.v.); (2) of mental TYPE (q.v.); (3) of mental differences of the sexes (see SEXUAL CHARACTERS); (4) of GENIUS (q.v.); (5) of mental DEFECT (q.v., also special types of defect); (6) of the CRIMINAL (q.v., also CRIMINOLOGY); (7) of classes, professions, &c., considered as based upon individual differences. Cf. VARIATIONAL PSYCHOLOGY.

Literature: BIBLIOG. G, 1, e; lists, sub verbo, in the Psychological Index, 1 ff.; BINET and HENRI, Année Psychol., ii. (1896) 411 (a résumé and exposition); DILTHEY, Sitzber. Akad. Wiss. Berlin (1896), 295. (J.M.B., G.F.S.)

Individual Selection: Ger. Personalselektion (Weismann); Fr. sélection entre individus (Y.D.), sélection individuelle (better than personnelle -- J.A. Thomson); Ital. selezione individuale. The survival of the individual organism or animal under the operation of NATURAL SELECTION (q.v.), as distinguished from the survival of parts, cells, germinal elements, &c. (cf. INTRASELECTION), which are supposed to be selected by an analogous method.

This rendering of Weismann's Personalselektion for the original Darwinian view of the survival of the individual -- for which, moreover, it was earlier used -- is better than the literal translation 'personal selection.' Personal selection suggests 'conscious selection' by a person, and it is better to reserve it for that. See SELECTION. (J.M.B., C.L.L.M.)

Individualism: Ger. Individualismus; Fr. individualisme; Ital. individualismo. (1) Exclusive or excessive regard for self-interest.

(2) The doctrine that the pursuit of self-interest and the exercise of individual initiative should be little or not at all restrained by the state, and that the functions of government should be reduced to the lowest possible terms.

Definition (2) is a product of the thought of the middle of the 19th century. The views of Bentham, Ricardo, and the elder Mill were derived largely from Adam Smith and the French Encyclopedists, and they found complete formulation in J. S. Mill's Liberty and Spencer's Social Statics. These works remain the standard defence of individualism, which differs from anarchism in recognizing the rightfulness of government to maintain order and to enforce equality of liberty. In his later work Spencer defends individualism on the ground that individual initiative is a normal and state action, in most instances an artificial factor in social evolution. The views opposed to individualism are classed together under the term SOCIALISM (q.v.). (F.H.G.)

Individualistic: Ger. individualistisch; Fr. individualiste; Ital. individualistico. (1) In sociology: applied to theories which advocate or imply INDIVIDUALISM (q.v.). (J.M.B.)

(2) In ethics: applied to those theories which derive the moral ideal or standard from the nature -- desires or conscience -- of the individual man.

All forms of EPICUREANISM, as well as the MORAL SENSE theory of ethics, and most forms of INTUITIONISM are thus individualistic (see those terms and ETHICAL THEORIES). The chief difficulty of such theories lies in bringing out the grounds and place of social duty. Cf. Sorley, Eth. of Nat., chaps. ii-iv. (W.R.S.)

Individuality: Ger. (1) Einzelheit, (2, 3) Individualität; Fr. individualité; Ital. individualità. (1) The quality or character belonging to an individual, as single. (2) The ethical qualities or dignity properly pertaining to an individual. (3) In case of character, the qualities which especially distinguish one individual person from another. See INDIVIDUAL, and IDENTITY (the different topics). (J.R.)

Individuation: see INDIVIDUAL, and IDENTITY (individual).

Indivisibility: see DIVISIBILITY.

Induction [Lat. inductio, from in + ducere, to lead; a word applied to Cicero -- and probably first by him, as Quinctilian seems to think -- to transfer Aristotle's epagwgh]: Ger. Induction; Fr. induction; Ital. induzione. (1) Inference from particular cases to a general conclusion. See INFERENCE, and REASONING.

(2) The method of procedure known as inductive reasoning, which makes large or exclusive use of inductive inference. See BACONIAN METHOD, and SCIENTIFIC METHOD.

The two forms of inductive inference generally distinguished are 'perfect' and 'imperfect.' In the former the conclusion rests upon confirmatory knowledge of all the cases which this general conclusion covers; in the latter, the conclusion covers cases which have not been actually experienced. 'Simple' or 'raw' induction by simple enumeration (inductio per enumerationem simplicem) is also distinguished from critical or methodical induction, which is inductive method criticized and organized for the purposes of research. This latter takes cognizance of the proportion of positive to negative cases, of variations of all sorts, of partial and compound results, and makes use of hypothesis and experimentation.

In the history of induction the names of Aristotle, Bacon, and Mill are eminent. Aristotle made the ideal of induction (epagwgh) perfect enumeration of cases. With Bacon induction was reinstated as scientific method (see BACONIAN METHOD for particulars). Mill grounded inductive inference as such upon the 'uniformity of nature,' which he makes the foundation of all knowledge, finding in it the 'natural tendency of the mind to generalize its experiences' (Logic, Bk. III. chap. ii. § 1). Mill, following Whately, made induction not a distinct type of argumentation, but a SYLLOGISM (q.v.; see also REASONING), of which the major premise, stating the universal principle of uniformity, is suppressed. Mill's discussion is a classical contribution to the theory of scientific method; the criticisms of it are aimed not so much at the theory of inductive procedure, as at the metaphysics which underlies his theory of UNIFORMITY OF NATURE (q.v.).

The principal theoretical question arising in connection with induction is that of the universally or universal validity of the conclusion. Here a critique is necessary in which discriminations are made concerning the nature of the assertion arrived at in the particular case. If, for example, we are dealing with judgments based on experience -- a posteriori synthetic judgments, such as 'the stone is hard' -- the conclusion, apart from other grounds of inference, is limited to what has been called a 'reasonable expectation' as to the hardness of other stones; an expectation which, however, rapidly gains in force as uniform experience continues. In the case, however, of a judgment of cause -- such as 'the sun warms the stone' -- the inference to other cases would include the condition -- which in this instance we call cause -- of the presence of the sun; and the warmness of future stones will be said to be necessary when that condition is fulfilled. In this latter case we are no longer dealing with the 'natural tendency to generalize,' but with an application of a universal judgment, from which we deduce the particular cases. It is only in these latter cases that the principle of uniformity, which is the logical justification for our expectation, is really invoked. We count on uniformity in the logical sense only where we postulate necessity or universal connection; and it is genetically the growth of experience which leads us to abandon reasonable expectation and develop inductive method as opposed to mere inductive inference. The child would say, 'All stones are warm'; the scientist, 'Stones exposed to heat become warm.' The progress of science is by (1) the formulation of a 'reasonable expectation,' embodied in a hypothesis; (2) the devising of crucial experiments or observations where-with to test the hypothesis by bringing the phenomenon under a category of necessary dependence; that is, to show that the connection observed is not merely a repetition of like cases, but includes some one or more antecedent conditions without which the consequent phenomenon would not occur. So we have Mill's method of DIFFERENCE (q.v.), and the other rules called 'canons of induction.' See CONCOMITANCE (logical), and AGREEMENT (method of); cf. also ANALOGY (in logic).

(3) The actual prediction of cases in kind, or the deduction of new phenomena from the conclusion thus arrived at.

Literature: BACON, Nov. Org.; MILL, Logic; the textbooks on logic (notably those of SIGWART, LOTZE, WUNDT) and on inductive logic; the literature cited under REASONING and SCIENTIFIC METHOD (notably the works of WHEWELL, JEVONS, VENN). See also BIBLIOG. C, 2, p, and extensive citations in EISLER, Wörterb. d. philos. Begriffe, 'Induction.' (J.M.B.)

Induction (in education). The process of reasoning from particulars to generals as a stage in educational method.

In Herbartian terminology, induction is the second of the three chief stages of a rational method; the first being the apperception of observed facts, and the last the deductive application of the generalizations derived by means of the middle, or inductive, process. See METHOD (in education).

Literature: McMURRY, Method of the Recitation, 170-87, and General Method, 122-44; HARRIS, Psychologic Foundations of Educ., 78-89. (C.DE.G.)

Industrial [Lat. industrialis, pertaining to industry]: Ger. gewerbthätig, industriell; Fr. industriel; Ital. industriale. (1) Pertaining to industry, without restriction.

(2) Pertaining to manufacturing industry in particular.

Industry in the general sense (of human labour of any kind) is as old as the Latin industria. Industry, as manufacture, is distinguished from agriculture and trade by Quesnay (Tableau Economique, 1758) and by Adam Smith (Wealth of Nations, iii, i, end, &c., 1776). The adjective has shared the fate of the noun, and the restricted sense is now the more common. In either its wide or its narrow sense it is to be distinguished (as colourless) from 'industrious,' a term of praise. It seems to owe currency to St. Simon. Cf. INDUSTRIALISM. (J.B.)

Industrialism: Ger. Industriesystem, Industrialismus; Fr. industrialisme; Ital. industrialismo. The organization of labour in manufacture.

Lotz (Grundbegriffe d. Nat-ök., 1811) used Industriesystem for Adam Smith's economic system, as opposed to physiocracy and mercantilism. The word Industriesystem would now mean the system of large production in manufacture (see Lexis, sub verbo, in Handwörterb. d. Staatswiss.). St. Simon used système industriel for his own organization of labour, and industrialisme as its synonym. Comte used this last, as Spencer 'industrialism,' to express the condition of a people or an age devoted mainly to manufacture as opposed to war ('militarism' indicating the dominance of the last). Cf. INDUSTRIAL. See Palgrave's Dict. of Polit. Econ., 'Industrial Régime.' (J.B.)

Industry [Lat. industria, diligence]: Ger. Gewerbe, Industrie; Fr. industrie; Ital. industria. (1) Organized economic activity.

(2) Specifically, the application of labour to goods in such a manner as to presumably increase their value.

Industry, in this second sense, is distinguished from trade, where the profit is made by buying and selling; also, less sharply, from agriculture, where the labour is applied to land rather than to goods. (A.T.H.)