DICTIONARY OF
PHILOSOPHY AND PSYCHOLOGY

Habeas Corpus [Lat.]. A form of writ designed to secure the speedy release of any one unlawfully confined. Its issue is a matter of right, and the procedure summary.

A similar remedy was afforded by the Roman praetor, by the interdict 'de homine libero exhibendo' (Dig. x1iii. 29). The English Habeas Corpus Act, 31 Car. II, chap. ii (given in full in Lieber's Civil Liberty, Appendix, 489), is the foundation of the statutes upon this subject of the United States and the several states. The writ is prayed out by, or in behalf of, the prisoner, and directed to the person who holds him in custody, who is required to produce him before the authority issuing the writ, within a time designated, together with a statement of the cause of his detention. If this cause is adjudged to be insufficient, the person will be forthwith discharged.

Literature: see also, with regard to the Roman law processes of this nature, Dig., x1iii. 30, De liberis exhibendis, &c.; SOHM, Inst. of Roman Law, § 88; DEMELIUS, Die Exhibitionspflicht. (S.E.B.)

Habit [Lat. habitus, from habere, to have]: Ger. Gewohnheit; Fr. habitude; Ital. abito, abitudine. (1) In psychology: a mental function whose repeated performance results in progressively better accommodation, and is accompanied by a feeling of familiarity and increased facility. The function itself is called a habit.

The abstract term habit is applied to the increased accommodation, familiarity, and facility, as in the expression 'due to habit.' The law of habit in psychology is the generalization that any function becomes thus modified and organized with repeated efforts. The inquiry into the reasons for habit leads to an analysis in which the elements of conation are most marked as passing from the type represented by effort (volitional conation) through gradual modification to impulse (non-volitional conation). Habit thus denotes the progressive modification of the conditions which determine a function through a series of changes, and as such is considered a genetic principle of the first importance: the principle of formation and conservation of type in mental operations. Thus considered, it is in contrast with the genetic principle of ACCOMMODATION (q.v.), which generally requires the modification of habitual performances.

(2) In neurology and physiology: a function which has become relatively organized and fixed. The psychological character noted above, whereby the conation involved passes from the volitional gradually to the non-volitional stage, is revealed on the organic side by the principle of so-called 'downward growth' or FACILITATION (q.v.) in the nervous system.

(3) In biology: an individually acquired function. Habit is thus sharply distinguished from INSTINCT (q.v.). A different usage -- mainly by descriptive zoologists -- extends the term habit (Ger. Habitus; Fr. moeurs) to include all specific actions of animals, whether instinctive or acquired. This is not to be endorsed, since the only possible hypothesis on which the instincts of animals can be brought under the conception of habit as used in psychology and physiology is that of LAMARCKISM (q.v.), according to which the instincts have been acquired gradually as so-called 'race-habits.' Apart, however, from the possible truth of that hypothesis, it is better, both for consistency and for clearness in discussion, to distinguish that which is individually acquired from that which is physically inherited. An extreme form of this usage is current among botanists, who speak of the habits -- of growth, &c. -- of plants. (J.M.B.- G.F.S.)

Literature: HAMILTON, Lects. on Met., XVIII. iii; REID, Active Powers, Essay III; HARTLEY, Observations on Man, Prop. XXI; LLOYD MORGAN, Habit and Instinct; GROOS, The Play of Animals, and The Play of Man (Eng. trans.); SCHNEIDER, Der thierische Wille, and Der menschliche Wille; BALDWIN, Ment. Devel. in the Child and the Race. Also general and genetic works on psychology, and BIBLIOG. G, 2, m. Further (in biology): HERBERT SPENCER, Principles of Psychology; A. WEISMANN, Essays on Heredity; H. EIMER, Organic Evolution; WALLACE, Darwinism; ROMANES, Mental Evolution in Animals. (C.LL.M.)

For references to the scholastic authorities, and on their usage, see EISLER, Wörterb. d. philos. Begriffe, 'Habitus.' (J.M.B.)

Habitat [Lat. habitare, to inhabit]: Ger. Wohnsitz; Fr. habitat; Ital. abitato. The local environment of an animal or plant. See ENVIRONMENT, and MILIEU. (C.LL.M.- J.M.B.)

Habituation: Ger. (1) Einübung, (1, 2) Gewöhnung; Fr. accoutumance (TH.F.); Ital. assuefazione, (l') abituarsi (to habituate). (1) The becoming accommodated or habituated with respect to the performance of a given function. Cf. EXERCISE (1), PREPARATION, and TERMINOLOGY (German), 'Einübung.'

The term drill is also used, especially in cases in which an external authority imposes the exercise for purposes of training, &c. (J.M.B.)

(2) A tendency set up in the course of an experimental series, to judge of a given number of that series in the terms of foregone judgments. It is the 'becoming habituated to the expression of a given judgment.' Cf. HABIT, and see DISPOSITION. (E.B.T.)

Hades [Gr. "AidhV]. The name employed by the translators of the Septuagint, and by the writers of the New Testament, for the sphere where the souls of the departed dwell.

The term Hades is common in Greek, from Homer down. In dealing with the Hellenic conception, care must be taken to differentiate between Hades (otherwise Aïdes, Aïdoneus, and Plouton), the deity -- brother of Zeus and Poseidon -- and Hades, the underworld or abode of the dead. Here we are concerned with the latter only. In the poems attributed to Homer, Hades appears as the dwelling-place of shadows. On the whole, these shades continue there essentially the life from which they have departed, being engaged in similar or identical occupations; but this existence is, as it were, a species of trance -- its unreality, bloodlessness, joylessness, comfortlessness form the striking characteristics (cf. Odyssey, xi). Its inhabitants are veritable ghosts that squeak and gibber. Or, as Achilles says relating his vision of Patroclus' shade: 'So spake he, and stretched out his hands but grasped him not, for vapour-like the spirit vanished into the ground with squeaking, gibbering cry. . . . Ah me! truly then there is in the dwellings of Hades a phatom, but freneV (i.e. passions, affections, emotions, will) it hath not at all' (cf. Iliad, xxiii. 66 f.). The pathos of loss would seem to be the idea which Homer most associated with the inhabitants of the nether world. In a word, the view of the future life represented by him is non-religious; that is to say, it offers a reply to the quasi-philosophical question, What becomes of the dead? -- a reply, moreover, which, to this stage, has no special connection with religion, because not involving any ideal of a higher life. By the time of Pindar this has changed, and Hades sometimes appears as a place where rewards and punishments are meted out (cf. Olymp., ii. 95 f.; Fragm. Thren., ii and iii). Moral considerations make their appearance here, and, for reasons connected with the development of Greek culture, which we still know but imperfectly, this progressive expansion of ideas connected with Hades continues in the later writers, becoming more spiritualized, more distinctively religious, till, in the end, the squealing ghosts of Homer give place to the Justice of Sophocles, dwelling in the underworld, and ruling even men's lives; and to Plato's argument for the immortality of the soul. The movement is from a merely imaginative idea about the place of shades to a moral conception of the conditions which govern human life eternally on account of its very constitution.

In the Septuagint, Hades is, as a rule, the translation of the Hebrew word Sheol, which occurs frequently in the Old Testament.

The conceptions of Hades are, on the whole, negative. While souls continue to exist there, they are conceived of as stripped of the qualities which most characterize the living; and few positive traits are added. The ideas of separation from the living, of cheerlessness, of absence of all the moral and social determinations that mark human life, predominate. In the Apocalyptic literature, the conceptions tend to become slightly more positive, as, for example, in the Book of Wisdom, where the idea of moral distinctions appears; while, in the still later Rabbinical literature, the doctrine of Hades as an intermediate state, which may be a preparation either for eternal bliss or for eternal misery, is formulated. A very notable fact is that the word is used only on ten distinct occasions in the New Testament. Here, once more, the negative tendencies of the Old Testament are maintained, to such an extent indeed that, if we except the ethical implications of the word as used by Jesus (e.g. Luke xvi. 23), little difference can be traced. In a word, no doctrinal use can be made of the term. Cf. ESCHATOLOGY.

Literature: SALMOND, Christ. Doctrine of Immortality; BÖTTICHER, De Inferis; WEBER and SCHNEDERMANN, Jüdische Theol. auf Grund d. Talmud; OERTEL, Hades; HAMBURGER, Real-Encyc. f. Bibel u. Talmud; E. RHODE, Die Psyche; HARTWIG, Die Darstellung d. Unterwelt. (R.M.W.)

Haecceitas [Schol. Lat.]. This-ness or thing-ness. See LATIN AND SCHOLASTIC TERMINOLOGY. (J.M.B.)

Hagiographa [Gr. agioV, sacred, + grafein, to write]. One of the divisions of the Canon of the Old Testament: the Law, the Prophets, and the Writings or Hagiographa (sacred writings). Under the last are included the following books: -- Psalms, Proverbs, Job, Song of Songs, Ruth, Lamentations, Ecclesiastes, Esther, Daniel, Ezra, Nehemiah, and Chronicles. Many important questions with regard to the formation of the Old Testament Canon are involved in this division and nomenclature. See CANON.

Literature: an excellent and most compact summary is ROBERTSON, The Old Testament and its Contents; GEIGER, Nachgelassene Werke, iv; REUSS, Hist. of the Canon of Holy Scripture (Eng. trans.); FRANCIS BROWN, in the J. of the Soc. of Bib. Lit. and Exegesis (1882), 95 f.; KAUTZSCH, Hist. of the Lit. of the O. T. (Eng. trans.); the relative arts. in Herzog's (German) and Lichtenberger's (French) Encycs.; Hastings' Dict. of the Bible; Cheyne's Encyc. Biblica. (R.M.W.)

Hagiology [Gr. agioV, sacred, + logoV, word, reason]: Ger. Heiligenlegenden; Fr. hagiologie; Ital. Agiologia. The section of ecclesiastical history which deals with the saints of the Church -- their lives, their achievements, the reasons for their CANONIZATION (q.v.).

Naturally, hagiology has received more attention from Roman Catholics than from Protestants. It may be usefully studied by those interested in philosophy of religion, from the historical and archaeological sides, and particularly for the light that it casts upon the psychology of religion.

Literature: this is enormous, and must be sought in bibliographies under specific names. The works on Anselm, Aquinas, Albertus Magnus, Francis, Bernard, Catherine of Siena, and Eckard are specially important from the side of philosophy of religion. (R.M.W.)

Halacha and Haggada [Heb.]. The two divisions of the Midrash.

Midrash denotes the exegesis, exposition, and illustration of the 'Law of Moses,' which, beginning after the return from the Exile, continued to occupy the attention of the Jewish ecclesiastical schools with increasing exclusiveness. Halacha is the name given to the interpretation of the sense of the Hebrew Scriptures; it was formulated chiefly in the Rabbinical schools, and was at once legal and highly casuistical. Haggada is the name given to the stories, legends, parables, and so forth which served to illustrate the Law. It was practical, rhetorical, and quasi-popular-homiletical, as a theologian would say. See TALMUD.

Literature: WÜNSCHE, Bibliotheca Rabbinica; WEBER and SCHNEDERMANN, Jüdische Theol. For the general atmosphere in which this interpretation grew up, see SCHÜRER, The Jewish People (Eng. trans.); HAUSRATH, New Testament Times (Eng. trans.). (R.M.W.)

Hallucination [Lat. hallucinatio]: Ger. Hallucination; Fr. hallucination; Ital. allucinazione. (1) The perceptual construction of an object which has in its construction no elements of external reality.

(2) The object thus perceived. (J.J.- J.M.B.)

Since the days of Esquirol (1838) an hallucination has been distinguished from an ILLUSION (q.v.) by the fact that in the latter a misinterpretation of an actually existent object is involved, while the true hallucination has no really external starting-point. This distinction, although practically valid, must not be drawn too rigidly, for in many cases the two approach one another closely. Illusions involve some elements of hallucination, and many hallucinations originate in a more remote external suggestion. See ILLUSION.

In medicine: the existence of hallucinations has been recognized from the time of Hippocrates; and their prevalence in insanity has always served as one of the popular characteristics of that state. The explanation of hallucinations and illusions was, until modern times, largely along the lines of possession or influence from the outside. Their subjective nature came into serious recognition towards the opening of the present century, and Esquirol (1772-1840) was influential in establishing their scientific importance. Historically, hallucinations have played an important part among all nations, especial significance being attached to appearances which presented themselves to great men at critical times.

Occurrence. Hallucinations, while specially characteristic of insanity, and of disturbed conditions of the nervous system, undoubtedly occur in perfectly normal persons; but the frequency with which they occur in states of fatigue, ill-health, or mental anxiety is most suggestive. The census of hallucinations gathered by the Society for Psychical Research indicates a wide dissemination of hallucinations in the sane; the numbers given, however (12 per cent. in all; 9^.75 per cent. in men, 14^.5 per cent. in women), are probably in excess of their actual occurrence. Hallucinations are most frequently met with in monomania (so-called delusional insanity), paranoia, and melancholia, but are not uncommon in mania. There is considerable diversity of statement in regard to the prevalence of hallucinations in mania and melancholia; this is largely due to differences of classification of these disorders, as well as to more minute differentiation between hallucinations and delusions in connection with these states (Parish, as below, 21 ff.). How far the vagaries and elaborate fancies of general paralysis are of the hallucinatory type is likewise variously stated (Parish, as below, 25-6); about one-third of all cases seem thus affected. Hallucinations may occur in the epileptic aura, in post-epileptic states, and in hysteria; and are characteristic of the action of various drugs (see PSYCHIC EFFECTS OF DRUGS). Acute bodily diseases, fevers, fasting, and exhaustion, dream-like states, certain forms of artificial hypnosis, and forms of heart trouble are also apt to induce hallucinations.

Varieties. Hallucinations are most frequently divided according to the sense which is affected; if affecting only one sense they may be termed simple; if more than one sense, compound. In the case of the insane it is important to distinguish between those which are recurrent and reflect the dominant mental tone, and those which are sporadic and unrelated to the mental tone. The two senses which are far more commonly affected than any others are sight and hearing. Amongst the sane about 60 per cent. of hallucinations are visual, 33 per cent. auditory; but this may readily be interpreted to mean that visual hallucinations are the more striking and the more apt to be remembered. Amongst the insane, auditory hallucinations seem fully as frequent as visual, owing mainly to the prevalence of the hallucination of hearing voices. Smell and taste hallucinations may occur, but it is difficult to eliminate some organic basis of sensation for these. Tactile hallucinations, hallucinations of the muscular sense, and of the organic sensations likewise rarely appear as individual hallucinations, however important they may be in contributing or originating the elaborate delusions in which other senses co-operate. Amongst the sane there was recorded one case of hallucination of more than one sense, to seven cases confined to one sense; of these complex hallucinations two-thirds are visual and auditory. No adequate statistics on this point exist for the insane; but the relations are probably not very different. Another variety of hallucination is the negative hallucination, occurring mainly as the result of hypnotic suggestion (see HYPNOSIS). In this the subject fails to see what is actually present; he may thus ignore a piece of furniture, an individual, a certain word or letter on a page, &c. The psychological process here involved is very different from that of the ordinary positive hallucination, which may be similarly aroused by hypnotic suggestion. Other forms of hallucination commonly described are the hypnagogic hallucinations, which occur in the transitional states in going to sleep and in waking from sleep; motor hallucinations, in which the patient appears to move while really at rest (cf. ILLUSIONS), or feels that he is flying, walking in air, &c.; unilateral and hemiopic hallucinations, which appear to one eye or to one ear only; and so on.

Illustrations. Human faces and figures are a frequent form of visual hallucination, often assuming terrifying expressions; animal forms are common. Both frequently move and take part in dramatic action. Mysterious signs, flashes of fire, areas of colour may appear, as in the visions of religious ecstatics. The kaleidoscopic changing of forms that appears in opium and other drug intoxication is also characteristic. In the complex hallucinations (those of persecution particularly), what first appears as a voice may later assume a definite shape. The variety of such delusions is endless, being determined largely by the dominant emotional tone and the personal temperament. The mysterious voices of one age become communicated through an invisible telephone in another; or the magic action by witchcraft becomes a form of mesmerism or of electricity. In all such cases the starting-point and specific nature of the hallucination is of greatest significance; its development and elaborations are too variable for psychological interpretation. Voices are perhaps the most prevalent form of hallucination, and frequently dominate the patient's entire conduct. As already indicated, hallucinations of touch are apt to be of the form of paraesthesia. Abnormal sensations are misinterpreted; creeping sensations become the attacks of ants or vermin; anaesthesias lead to conceptions of the limbs as made of wood or glass, the absence of a stomach, and the like. Changes of personality may be similarly conditioned. Visceral disturbances may lead to the presence of olfactory hallucinations -- bad odours. A perverted taste may lead the patient to detect imaginary poison in his food. This group of quasi-hallucinations seldom appear alone, but cooperate with other hallucinations in the formation of delusions under the dominance of the prevailing mental tone.

Theories. While the special senses are concerned in the origin of hallucinations, they afford no explanation of the hallucination itself. For hallucinations are not mainly of crude sensations like flashes of light and sudden noises, but of definite objects and scenes; moreover, persons who have become blind or deaf may be subject to hallucinations in the domain of the lost sense. While admitting that sensory changes may induce hallucinations (as in intoxication, &c.), these are secondary to the main phenomenon, which is of central origin. Theories (Ferrier, Tamburini) which ascribe the initial impulse of the hallucination to the highest cortical (ideational) centres may be termed centrifugal. Such views hold that when an irritation begins in the appropriate highest centre (or, in another view, is brought to that highest centre from an irritation in the subcortical centre), and proceeds outward (under certain favourable but not clearly determined conditions), it causes an hallucination, just as the reverse process normally causes a true perception. This view, according to which the hallucination is projected outward and materialized by a process the reverse of normal sense-perception, seems to be favoured by the fact that certain persons can produce hallucinations by an action of the will, that hallucinations do not occur in states of severe mental defects (idiocy, dementia), that the same factors are important in actual life and in hallucinations, and further, in recent discussions, by the fact that such hallucinations are doubled when a prism is held in front of the eye, are coloured when seen through coloured glass, and so on. That this type of theory is inadequate can readily be shown. To begin with, the fundamental process involved cannot be regarded as plausible or physiological; the sporadic cases of voluntary hallucinations are far too few to be significant; the doubling and colouring of the hallucination is perhaps an inference (more or less unconscious) from what happens to normal objects.

An adequate theory can be formed only on the basis of a more exact knowledge of the relations of cerebral centres than we now possess. The most helpful theories (those of Meynert, James, Kandinsky, Parish, and others; see Parish, as below, 132-52) proceed on the basis of an identity of the sensory and reproductive centres, and exhibit the hallucination as a disturbance of the usual relation between the particular perceptive centre and its associative bonds. It is a state of dissociation, which is the common point of all hallucinatory states (Parish); it is the suppression of the activity of the highest cortical centres which makes possible the undue excitement of the subcortical centres, which in turn occasion hallucinations (Meynert); it is the over-accumulation of nerve-currents (owing to the absence of free communication with neighbouring cells) which acts like an explosion and produces an hallucination (James). While these theories are helpful, no one of them can be said to present an adequate account of what goes on in the hallucinated mind; such defect being the almost necessary result of our defective knowledge in regard to the physiological counterparts of normal perception, association, and reproduction.

It has been held (Baldwin) that hallucination, like illusion, arises from a disturbance of the normal relation which holds in all perception between central and peripheral elements. When for any reason the central factor is over-stimulated or the peripheral is ineffective, the normal interpretation of the objective is disturbed, and an assimilation of data takes place, in which central processes -- images, schemes, beliefs -- dominate. Cf. ILLUSION.

For the relation of hallucination to insanity see SANITY AND INSANITY, EPILEPSY, and HYSTERIA; see also ILLUSION, DELUSION, DREAM, INTOXICATION, HYPNOSIS, PSYCHIC RESEARCH, and VERIDICAL HALLUCINATION.

Literature: the most comprehensive study, from the normal point of view, is EDMUND PARISH, Hallucinations and Illusions (1897), especially chaps. i-iv (with full references). See also the Psychologies of JAMES, TAINE, BALDWIN. Pathological: SANDERS, art. Sinestäuschungen, in Eulenburg's Real-Encyk., xviii; TAMBURINI, Riv. di Freniat. (1880); HOPPE, Erklärung d. Sinnestäuschungen bei Gesunden u. Kranken (4th ed., 1888); MORSELLI, Semej. malat. ment.; KANDINSKY, Krit. u. klin. Betrachtung im Gebiet d. Sinnestauschung (1885); SNELL, Allg. Zeitsch. f. Psychiat., 1. 534; BAILLARGER, Mém. de l'Acad. Roy de Méd., xii; KRAEPELIN, Psychiatrie, and Vtljsch. f. wiss. Philos., v; KRAFFT-EBING, Die Sinnesdelirien (1864); A. MAYER, Die Sinnestäuschungen (1869); ZIEHEN, Psychiatrie (1894). Historical mainly: JOH. MÜLLER, Ueber phantastische Geisteserscheinungen (1826); ESQUIROL, Ment. Pathol. (Eng. trans., 1845); BRIERRE DE BOISMONT, Hallucinations (trans., 1859); GRIESINGER, Ment. Pathol. (Eng. trans., 1867). Many of the books on mental diseases contain interesting treatment of hallucinations, e.g. Twentieth Cent. Pract. of Med., xii. 80-9. (J.J.)

Hamilton, Sir William. (1788-1856.) Eminent Scottish metaphysician, born at Glasgow, and educated at Glasgow and Oxford. Intended for a physician, he decided to study law. In 1817 and 1820 he travelled in Germany. Not succeeding eminently as an advocate, he applied for the chair of moral philosophy in Edinburgh, upon the death of Thomas Brown, but was not appointed (1820). In 1821 he was made professor of civil history at Edinburgh. In 1836 the chair of logic became vacant at Edingburgh, and Hamilton, after an exciting candidacy, was elected. He continued to lecture until his death, May 6, 1856.

Handwriting: Ger. Handschrift; Fr. écriture; Ital. scrittura. The material recording of thought by imitative or conventional signs, for purposes of social communication, through movements of the hand.

The transition from the purely imitative to the purely conventional, from the pictograph to true handwriting, was probably very slow. The essential fact that the sign, either imitative or conventional, records and communicates a meaning, is present to both; but the former no doubt illustrated a stage of mental progress having generalization without much abstraction. It is reasonable to suppose that the evolution of writing, following after that of speech, reacted to aid the evolution of abstract thought.

The psychological problem of handwriting deals with the acquisition of the necessary movements, together with the control and inhibition involved in the progressive execution of the series of movements. Theories from the purely psychological point of view have been developed by Goldscheider (Zeitsch. f. Psychol., xxiv, 1892) and Baldwin (Ment. Devel. in the Child and the Race, chap. v. § 2). They agree in making handwriting an imitative function, taking its start in 'tracery imitation' (the malende Reproduction of Goldscheider), and developing by the gradual association of certain sensational series: a 'visual form' series, a 'kinaesthetic movement' series, and a remote 'optical' series; of which, however, Goldscheider recognizes only the two last. The two theories differ as to which of these is the original copy series (Goldscheider saying the 'optical' and Baldwin the 'visual form' series), and in the relative place of the various sensational elements in the acquisition of control. Goldscheider has shown (loc. cit.) by experiment that the 'kinaesthetic movement' series involves pressure sensations entering into the resistance of the plane written on. For troubles and variations in handwriting based on the preceding analysis see Godscheider (loc. cit.), and the topics AGRAPHIA and MIRROR WRITING. Cf. also GRAPHOLOGY (q.v. for matters pertaining to handwriting as expressive of character, &c.).

Literature: as referred to; BROADBENT, on Handwriting of the Blind, Brit. Med. J. (1876), i. 435; the manuals of Psychiatry of ERLENMEYER, EMMINGHAUS, and MORSELLI. Also the titles given under the topics referred to. (J.M.B.)

Haploscope: see LABORATORY and APPARATUS, III, B, (a), (10).

Happen and Happening: see EVENT.

Happiness [ME. hap, chance]: Ger. Glück; Fr. bonheur; Ital. felicità. A desirable and, on the whole, pleasurable condition of life.

The definition of J. S. Mill (Utilitarianism, chap. ii) -- 'by happiness is intended pleasure and the absence of pain; by unhappiness, pain and the absence of pleasure' -- expresses the ordinary acceptation of the term in English, and of its equivalents in most modern languages.

As the traditional rendering of the Greek eudaimonia, the term is sometimes used in a less precise sense for the most desirable -- or for any desirable -- condition of human life, whether that condition be, in ultimate analysis, reducible to terms of pleasure, or not. 'Blessedness' is an alternative rendering of eudaimonia, not so constantly associated with a hedonistic interpretation; and  'wellbeing' is also used. See GREATEST HAPPINESS, and EUDAEMONISM. (W.R.S.- J.M.B.)

Haptics [Gr. aptein, to touch]: Ger. Haptik; Fr. haptique (not generally used -- L.M.); Ital. teoria del tatto, aptica (suggested -- E.M.). The doctrine of touch with concomitant sensations and perceptions -- as optics is the doctrine of sight, and acoustics that of hearing.

Suggested by Dessoir (Du Bois-Reymond's Arch., 1892), who made two subdivisions of the subject: (1) contact sense, and (2) pselaphesia -- corresponding roughly to passive and active touch; the term has since come into general use, though no universally accepted definition can be offered. It may cover (and this is probably its best use) the whole range of function of skin, muscle, tendon, and joint, and even of the static sense -- thus including the senses of temperature and pain, and the perceptions of position, movement, &c.; or it may be restricted to cutaneous sensations and perceptions in the narrower sense. (E.B.T.)

Literature: SANFORD, Course in Exper. Psychol., chaps. i, ii, and bibliographies; HENRI, Raumwahrnehmung d. Tastsinnes (1898); DESSOIR, loc. cit.; FUNKE, in Hermann's Handb. d. Physiol., iii. 2; HERING, ibid.; WEBER, in Wagner's Handb. d. Physiol., iii. 2 (this paper may be said to represent the first step in the science); MACH, Bewegungsempfindungen (1875); FULLERTON and CATTELL, Perception of Small Differences (1892); VON FREY, Abhandl. d. k. sächs. Gesell. d. Wiss. (1896), and Berichte, 1894-7; Zeitsch. f. Psychol., xx. 126; DELABARRE, Bewegungsempfindungen (1891); WUNDT, Physiol. Psychol. (4th ed.), i. 429; MÜNSTERBERG, Beitr. z. exper. Psychol., iv; MORSELLI, Semej. malat. ment. (1898), i; DRESSLAR, Amer. J. of Psychol., vi. 313 ff.; GRIFFING, Psychol. Rev., monograph, Suppl. i; M. F. WASHBURN, Philos. Stud., xi. 190 ff.; G. TAWNEY, Psychol. Rev., ii. 588 ff.; TAWNEY and HODGE, Psychol. Rev., iv. 591; F. KIESOW, Arch. Italiennes de Biol., xxvi. 417; Zeitsch. f. Psychol., xx. 126; BLIX, Upsala Läkare förenings Förhandlinger, xviii. 2, 7, 8; Zeitsch. f. Biol., xxi. 145; GOLDSCHEIDER, Gesammelte Abhandl., 1898; VIERORDT, Zeitsch. f. Biol., xii. 226, and Grundr. d. Physiol.; MÜLLER and SCHUMANN, Pflüger's Arch., x1v. 37; &c. (E.B.T.- L.M.)

Harmonics [Gr. armonikh, the theory of sounds]: Ger. harmonische Obertöne; Fr. harmoniques; Ital. armoniche. A word often used loosely in the sense of OVERTONE (q.v.). Strictly, the harmonics of a tone are other tones of which the fundamentals are partials of the original tone. See Helmholtz, Sensations of Tone (3rd ed.), chap. xxv. (E.B.T.)

Harmony (in acoustics) [Gr. armonia]: Ger. Harmonie; Fr. harmonie; Ital. armonia. (1) That element of a musical whole which arises from the simultaneous or immediately successive sounding of tones, in distinction from MELODY (q.v.).

In musical theory and in instruction harmony is the department dealing with the composition of tones for the production of musical effects. Harmony thus includes both consonances and dissonances; disharmonies are the discords not allowed by musical practice. (J.M.B.- E.B.T.)

(2) The words harmony and disharmony are often used loosely as the equivalents of CONSONANCE and DISSONANCE (q.v.).

(3) The terms sometimes correspond to degrees of indirect tone relationship. So used by Wundt, Physiol. Psychol. (4th ed.), ii. 71. (E.B.T.)

Harmony (in aesthetics). Applied, apart from music, to indicate any agreeable arrangement of forms, colours, or other qualities in an aesthetic whole, with special reference to some criterion of CONGRUITY or FITNESS (q.v.), whether implicitly or explicitly recognized.

Harmony does not exclude either conflict or CONTRAST (q.v.). They are rather means of augmenting its agreeable effects, through emphasis upon the unification of diversities, which constitutes its basal characteristic. This is illustrated by the conflicts in comedy and tragedy, and by the contrasts involved in the increasing use of broken chords in modern music. Harmony is distinguished from SYMMETRY (q.v.) by the disposition of parts or qualities in accordance with their aesthetic values, as determined by their relations to one another and to the whole of which they form the parts, rather than in accordance with their exact quantitative and mathematical values. It is distinguished from BALANCE (q.v.) in so far as this emphasizes the fact of a certain opposition among the parts of an aesthetic whole, while harmony emphasizes their intrinsic unity. It is distinguished from PROPORTION (q.v.) in that the latter is applied to quantitative relations, whereas harmony applies more specifically to qualitative relations.

The principle of harmony in its essential intention is not only fundamental in the Greek aesthetic consciousness and the development of Greek aesthetic theory, but it may also be said to involve the basal interest of Greek reflective thought in its attempt to reconcile the one and the many. Of musical origin, the principle first comes to light among the Pythagoreans, who appear to have applied the term primarily to the relation involved in the octave. Thence, among other developments, they extended its significance to the orbits of the heavenly bodies, in the doctrine of the harmony of the spheres. With Plato and Aristotle the principle gains a wider aesthetic implication in the analysis of the appropriate relations which the parts should sustain to the whole in a work of art; less explicitly with Plato and with relatively greater emphasis upon the value of the simplicity of pure unity; more explicitly with Aristotle and with greater emphasis upon the unity of variety, as in his account of the drama. In the Platonic system of thought, and in some degree characterizing all philosophy developed under its influence, the ethical conception of the good as the complete, the sound, the whole, the tempered, that which lacks excess, makes itself felt in the realm of aesthetic considerations. In both morals and art, therefore, as well as in metaphysics, the principle of harmony appears as central. In modern thought the solutions reached of the Greek philosophic problem lead to a less explicit emphasis upon harmony. It is recognized as a somewhat self-evident principle, although it gains a richer and more positive content through the stress placed upon its complementary principle, contrast, which in its more pronounced forms involves the extreme of permissible variety in the aesthetic unity. This enlargement of the principle in aesthetic theory is best reflected in art itself, by the enrichment of harmony through the increasing complexity of modern, as compared with ancient, music. For other aesthetic principles closely related see CONTRAST, EXPRESSION, and FORM.

Literature: for a typical instance of elaborate modern treatment see KÖSTLIN, Aesthetik (1869); BOSANQUET, Hist. of Aesthetic (1892); WALTER, Gesch. d. Aesthetik im Altertum (1893); SCHASLER, Gesch. d. Aesthetik (1872). See also HARMONY and MELODY. (J.R.A.)

Harmony (Cartesian): see PRE-ESTABLISHED HARMONY.

Harmony (in logic). Absence of all logical INCONSISTENCY (q.v.). (J.M.B.)

Harmony (Pythagorean): see Pythagoreans, under PRE-SOCRATIC PHILOSOPHY, and HARMONY (in aesthetics).

Harshness (of tone) [ME. harsh]: Ger. Rauhigkeit; Fr. rudesse du son; Ital. asprezza del suono. The terms harshness and roughness are predicated of musical sounds in several slightly different senses. (1) A stage in the perception of two simultaneously sounded tones intermediate between the discontinuity of beats and pure dissonance (Wundt, Physiol. Psychol., 4th ed., i. 474). (2) A characteristic of certain intervals constructed upon the same lower note, due to beating partials (Helmholtz, Sensations of Tone, 192-3, and Pop. wiss. Vortr., i. 88; Stumpf, Tonpsychologie, i. 203, ii. 521, 534). (3) A characteristic of deep tones in general, compared with which high tones are 'smooth' (Preyer, Elemente d. r. Empfindungslehre, 54; Stumpf, Tonpsychologie, i. 173). (4) The words point to the presence with tone of noise, or to the prominence in a compound tone of certain partials; as when we say that the tone of a string instrument or reed instrument is 'harsh' as compared with the tone of a tuning-fork or bottle-whistle. (E.B.T.)

Hartley, David. (cir. 1705-57.) An English philosopher, educated at Jesus College, Cambridge. He was educated for the Church; for conscientious reasons, however, he preferred medicine. He sought to explain mental facts by physiological.

Hate [AS. hatian, to hate]: Ger. Hass; Fr. haine; Ital. odio. An emotion characterized by the type of aversion (see APPENTENCE) which aims to damage or destroy, under conditions of more or less permanent restraint, limitation, or powerlessness, and the feeling-tone of intense ANGER (q.v.).

The relation of hate to anger is very obscure, the essential impulse to destroy being present in each, and the emotional excitement being largely common. The difference appears to introspection to consist in the sense of thwarting, limitation, or powerlessness, which accompanies hate. It is sometimes held that hate is more intellectual in its character than anger. This intellectual character of hate is doubtless real, but it arises from the knowledge or belief which results in the consciousness of being thwarted. The emotion of hate seems, when the opportunity of damaging the hated object occurs, to pass into anger or rage. The firm setting of the jaws and shaking of the head appear to be more prominently characteristic of anger when it passes over into hate.

Hate is usually made the direct opposite of love, but the relation is not so simple; for the opposite of anger is not expressed in any single term, though covered by the term LOVE (q.v.).

The element of relative permanence attaching to hate possibly arises from the same condition of limitation or thwarting, which needs a certain grounding or more or less extended series of reasons. Whatever its cause, it certainly appears in such expressions as 'rankling' hate, 'suppressed,' 'smothered,' 'cherished' hate -- expressions which are not usually applied to anger; on the contrary, anger is said to be in 'outbursts,' 'fits,' 'paroxysms,' &c.

Literature: see ANGER and EMOTION. (J.M.B., G.F.S.)

Haunted Swing: see ILLUSIONS OF MOTION AND MOVEMENT, II.

Hazard: see CHANCE.

Hearing [AS. hyran]: Ger. Gehör; Fr. ouïe, audition; Ital. udito. The special sense whose end-organ is the ear, whose nerve is the cochlear branch of the auditorius, and whose stimulus is sound. (J.M.B.- E.B.T.)

I. THE EAR [AS. eare]: Ger. Ohr; Fr. oreille; Ital. orecchio. Organ of hearing, and an important organ for equilibration of the body. On the side of audition the ear is the mechanism that transforms vibrations of the medium into sensations of sound. On the side of EQUILIBRIUM (q.v.) it yields sensations, along with those from skin, muscles, and eyes, which indicate position of the body at rest and the direction of its movements of rotation or translation. Recent investigations, notably those of Lee, have tended to demonstrate that these two distinct functions are associated with different parts of the auditory mechanism.

Comparative. Organs usually described as auditory are present in many jelly-fishes in the form of otocysts in the margin of the bell at the base of the tentacles. Lee's experiments with Ctenophores indicate that these are wholly organs of equilibration. Echninoderms present two kinds of organs, both probably for orientation of the body -- the one a modified spine, a true balancer consisting of a calcareous knob supported on a pivot and covered with ciliated epithelium, the cilia being longest about the neck; the other a true otocyst, found sometimes in great numbers in the cutis of the holothurians. Nearly all molluscs have a pair of otocysts, situated generally near the pedal ganglia (bivalves, lamellibranchs, and gastropods); but always innervated from the cerebral ganglia. In cephalopods these become highly developed organs of orientation with the so-called maculae and cristae acousticae, and are placed in the head close to the cerebral ganglia. From worms, as a class, specialized auditory organs are strangely absent. A very few genera of polychetes, however, have a pair of otocysts in one of the anterior segments. Arthropods are well provided with auditory organs. In the decapod crustacea they commonly occur in the basal joint of the antenules, but rarely they are placed, as in Mysis, in the endopodite of the last pair of swimming appendages. Auditory organs of insects consist of groups of peculiar cells, resembling ganglion cells, each provided with a sensory hair. These organs are situated most variously on the body -- on the different segments, on the antennae or mouth parts, on the wings or legs. In some insects the sensory hairs project from the surface, but in most cases they lie just underneath the surface, the chitin over them being commonly modified to act as a tympanic membrane. In vertebrates, the auditory organs are uniformly situated within the skull on either side near its base. In addition to the auditory capsule proper in fishes, the end-organs of the auditory nerve are widely distributed over the surface of the head and body as lateral line organs. (C.F.H.)

Structure. The ear has four parts: (1) the outer ear, comprising the auricle or pinna, and the auditory meatus for the collection and concentration of air-vibrations; (2) the middle ear, or tympanum, containing the auditory ossicles for transmitting and strenghthening these vibrations; (3) the inner ear, or labyrinth, comprising the vestibule, semicircular canals, and cochlea, with their specific sensory nerve termini; (4) the auditory nerve and its end-stations within the brain.

The parts of the auricle are indicated in the accompanying Fig 1. It is of relatively small significance to hearing in man, as compared with many of the lower animals, where it is not only large, but supplied with important muscles. This may be correlated with the well-known imperfection of our ability to discriminate the direction of sounds. The extreme variability of the auricle is due to its functional degradation, and this is doubtless the explanation of its anthropological importance in studies of degeneracy, &c.

Most of the lower vertebrates (Ichthyopsida) lack the middle ear, their aquatic environment rendering unnecessary any mechanism for increasing the intensity of sonorous vibrations. But the air-breathing vertebrates, from the higher Amphibia onwards, exhibit this mechanism in increasing complexity. The tympanic cavity and Eustachian tube are regarded as derivatives of the first, or spiracular, gill cleft of the lower fishes, while the auditory ossicles are apparently derived from bones of the facial skeleton of the fishes connected with the mandibular and hyoid arches.

The labyrinth is an intricate excavation in the temporal bone of the skull (the bony labyrinth), containing a closed membranous sac, the membranous labyrinth, fitting loosely the bony chamber, and separated from it by a lymph space, whose fluid, the perilymph, does not communicate with the similar fluid, or endolymph, within the membranous labyrinth. The parts of the membranous labyrinth are the utriculus, into which the semicircular canals open, each with an expansion or ampulla at one end, the sacculus, the recessus labyrinthi, and the cochlea. Their relations are shown by the accompanying Figs. 4 and 5. Each of these, except the recessus, contains a patch of sensory epithelium. The morphology and functions of these parts can be better understood after a rapid survey of their phylogenetic and embryological development.

In its embryological development, the human ear first appears as a thickened bit of ectoderm at the side of the medulla oblongata, which soon becomes depressed to form the 'auditory saucer.' At a later period this saucer is completely invaginated to form the 'auditory vesicle,' retaining, however, for a time its communication with the outer surface of the body. This condition is permanent in the sharks, the endolymph of the labyrinth communicating with the outer sea-water by the endolymphatic duct, just as the lateral line canals freely communicate with the surface by pores. In higher animals this connection is early lost, though the recessus labyrinthi is regarded as a vestige of that connection. The lining membrane of the auditory vesicle develops a patch of sensory epithelium, and as the vesicle becomes constricted into the several chambers comprising the labyrinth, an extension of this sensory patch grows into each chamber. These sensory areas then become separated by indifferent epithelium, and thus arise the three cristae in the ampullae, the macula utriculi, the macula sacculi, and the organ of Corti. The structure of all of these sensory organs except the organ of Corti is similar and very simple, the specific sensory cells being shorter than the indifferent cells, and provided with hairs which project into the endolymph. The base of these cells is embraced by the terminal arborizations of the corresponding nerve-fibres (see Fig. 6). This structure is essentially similar to that of the sensory organs in the lateral line canals of fishes.

The bony cochlea is formed somewhat like the interior of a snail-shell, with two and one-half turns of the spiral, and with a bony shelf or ledge, the lamina spiralis, extending outward from the axis, or modiolus. Within the spirals of the bony cochlea are three membranous canals: (1) The scala vestibuli communicates as its base with the perilymphatic space around the vestibule, whose fluid is caused to vibrate by the foot of the stapes, which plays in the fenestra ovalis between the middle ear and this space. (2) The scala tympani communicates at the apex of the spiral with the scala vestibuli, and at its lower end terminates at the fenestra rotunda. Sonorous vibrations entering the perilymphatic space pass up the cochlear spire through the scala vestibuli and down through the scala tympani, terminating at the fenestra rotunda, by whose membrane they are deadened or passed back into the middle ear. (3) The scala media, which occupies a position in the spiral between the other two scalae, is the only part of the cochlea derived from the original auditory vesicle; accordingly it contains the specific sensory apparatus (organ of Corti), and its cavity does not communicate with those of the other scalae. From the free edge of the spiral lamina of the bony cochlea two membranes which bound the scala media are stretched to the outer wall of the spiral canal. One of these lies in the same plane as the spiral lamina, and constitutes the basilar membrane, or floor of the scala media, separating it from the scala tympani and supporting the organ of Corti; the other is Reissner's membrane, forming the roof of the scala media and separating it from the scala vestibuli.

The organ of Corti is an elaboration of the ectodermal epithelium which covers the basilar membrane (see Figs. 7 and 8). Rising up from the basilar membrane are two sets of firm rods, the rods of Corti, which incline toward each other, uniting at the apex to enclose a tunnel which runs the whole length of the organ of Corti. The hair cells, or specific sensory termini, are arranged in a series internal, and one external, to the rods of Corti, the inner series comprising a single row of hair cells, the outer series three or four rows. All of these cells are supported by other indifferent epithelium cells. Running outward from the axis is a so-called tectorial membrane, which lies upon the free ends of the hair cells, and is supposed to act as a damper to their hairs, which project freely into the endolymph. Some authorities, however, believe that the tectorial membrane is an artifact, being really the long hairs of the hair cells broken off and matted together. The nerve-fibres terminate about the bases of the hair cells in arborizations similar to those found in the sense organs of the vestibule. As to the functions of the parts just enumerated, the most diverse opinions prevail; and as a matter of fact, we have no definite knowledge on these points. (H.H.)

Functions. Helmholtz early adopted a resonance theory of audition, and was first attracted to the rods of Corti as the possible resonators by which tones are analysed in the ear. The fact that they are not present in birds, and, further, that they are practically all the same length, size, and shape, led him to abandon them. He next fixed upon the fibres of the basilar membrane. These increase gradually in length from base to apex of the cochlea, and thus satisfy one of the requirements of the theory. Ayers maintains that the fibres of the basilar membrane are inadequate on account of their number, their physical constitution, and their arrangement with reference to the sensory cells, and he advances the theory that the hairs of the sensory cells are the only structures present that can properly act as resonators. The objection that the hairs are too short and too nearly the same length no longer holds, if we accept Ayers' results; and in this way the number of resonators is greatly increased, from 24,000 fibres of the basilar membrane to, according to Ayers' estimate, 385,000 sensory hairs.

Another theory that is gaining in prominence is the appropriately named 'telephone theory' of Rutherford. According to this the organ of Corti vibrates as a whole, giving to the auditory nerve the same number of stimuli as there are movements of the tympanic membrane and stapes, and these stimuli are analysed by the auditory centres in the brain. See AUDITORY SENSATION below in this article (III).

Lee considers the organ of Corti, or in the animal series the papilla acoustica basilaris, co-extensive with the function of audition in vertebrates, and is inclined to think that all the other sensory structures of the labyrinth mediate only sensations of equilibrium. His statement is: 'Wherever among vertebrates undoubted audition exists, there is present an additional group of sensory organs, the papilla acoustica basilaris. This does not exist in fishes, but appears first in the amphibia as an offshoot of the lagena, and in higher vertebrates constitutes the nervous portion of the organ of Corti of the cochlea.'

Lee's table of functions of various parts of the labyrinth is as follows: --

'I. Dynamical functions, in recognition of --

1. Rotary movements, mediated by cristae acousticae.

2. Translatory movements, mediated by maculae acousticae.

II. Statical functions, in recognition of --

3. Position in space, mediated by maculae acousticae.

III. Auditory functions, in recognition of --

4. Vibratory motions, mediated by papilla acoustica basilaris.' (C.F.H.)

The auditory, or eighth, cranial nerve has two divisions corresponding roughly, though not exactly, to the different sensory functions served by the internal ear. The vestibular branch supplies the superior and external ampullae and the macula utriculi, while the so-called cochlear branch supplies, in addition to the cochlea, the posterior ampulla and the macula sacculi. The last two branchlets are more properly separated from the cochlear nerve under the name ramus medius. The cochlear nerve in the strict sense is the chief, if not the only, nerve of audition, the other branches being chiefly concerned with the static sense. Accordingly their central connections within the brain are very different from those of the cochlear nerve. The ganglion (of Scarpa) of the vestibular nerve lies in the internal auditory meatus, and the central processes of its cells form the vestibular, mesial, or anterior root of the auditory nerve, which enters the brain ventrally and cephalad of the cochlear root, and connects with many different brain centres, but chiefly with the cerebellum. The ganglion (spirale) of the cochlear root lies in the axis of the bony cochlea. The central connections of this root are even more intricate than those of the vestibular root. In general it may be stated that these fibres first enter either the dorsal or the ventral cochlear nucleus. The central auditory path extends from the ventral nucleus by way of the trapezoid body, and from the dorsal nucleus by way of the striae acusticae (both root-fibres and secondary fibres in each case), to the region of the superior olive, partly crossed and partly uncrossed. The path then goes up by way of the lateral fillet to the inferior member of the corpora quadrigemina (postgeminum), which appears to be the general centre for the elaboration of higher auditory reflexes, and which is absent in animals which do not possess the cochlea. Its reflex connections are very numerous, notably with lower centres and with the pregeminum (optic reflex path). Other fibres extend from the post-geminum to the corpus geniculatum mediale, where they terminate among the cells of this nucleus. The cortical acoustic path begins from these cells, and terminates in the auditory sense area in the temporal lobe of the cerebral cortex.

Literature: H. AYERS, A Contribution to the Morphology of the Vertebrate Ear, with a reconsideration of its Functions, J. of Morphol., vi (1892); L. F. BARKER, The Nerv. Syst. and its Constituent Neurones (1899); A. BARTH, Beiträge zur Anatomie des Ohres, Zeitsch. f. Ohrenh., xvii; Ueber die Darstellung des häutigen Labyrinthes, Arch. f. Anat. u. Physiol., Physiol. Abth (1889); H. BEAUREGARD, Recherches sur l'appareil auditif chez les mammifères, J. de l'Anat. (1893); W. BECHTEREW, Ueber die innere Abtheilung des Strickkörpers und den achten Hirnnerven, Neurol. Centralbl., iv (1885); BOETTCHER, Rückblicke auf die neueren Untersuchungen ü. d. Bau der Schnecke, im Anschluss an eigene Beobachtungen, Arch. f. Ohrenh., xxiv (1886); H. HELD, Die centralen Bahnen des Nervus acusticus bei der Katze, Arch. f. Anat. u. Physiol., Anat. Abth. (1891); Die centrale Gehörleitung, ibid. (1893); P. C. LARSEN, Ein anatomischphysiologischer Beitrag zur Lehre von den Ossicula auditus, Anat. Anz. (1890); F. S. LEE, The Functions of the Ear and the Lateral Line in Fishes, Amer. J. of Physiol., i (1898); M. V. LENHOSSEK, Die Nervenendigungen im Gehörorgan, Verh. d. Anat. Gesell., Anat. Anz., viii (1893); Die Nervenendigungen in den Maculae und Cristae acusticae, Anat. Hefte, ix (1893); J. NIEMACK, Maculae und Cristae acusticae mit Ehrlich's Methylenblaumethode, Anat. Hefte, viii (1892); B. ONUFROWICS, Experimenteller Beitrag zur Kenntniss des Ursprungs des Nervus acusticus des Kaninchens, Arch. f. Psychiat., xvi (1885); B. A. RANDALL and H. L. MORSE, Photographic Illustrations of the Anatomy of the Human Ear, together with Pathological Conditions of the Drum Membrane and Descriptive Text (Philadelphia, 1887); RAUBER, Ueber d. Bau des Gehörlabyrinthes, Sitzber. d. Naturf. -Gesell. zu Leipzig, xii (1886); G. RETZIUS, Das Gehörorgan d. Wirbelthiere (Stockholm, 1884); also Biol. Untersuch., iii and v (1892 and 1893); N. RUDINGER, Zur Anatomie und Entwickelung des inneren Ohres, Monatssch. f. Ohrenh., xxii (1888); L. SALA, Ueber den Ursprung des Nervus acusticus, Arch. f. Mikr. Anat., x1ii; G. SCHWALBE, Lehrb. d. Anat. d. Sinnesorgane (Erlangen, 1887); Beiträge zur Anthropologie des Ohres, Festschrift f. Virchow, i; E. ZUCKERKANDL, Beitrag zur vergleichenden Anatomie d. Ohrthompete, Arch. f. Ohrenh., xxiii (1886). (H.H.)

II. SOUND [Lat. sonus]: Ger. Schall; Fr. son; Ital. suono. Sound, the stimulation of certain nerve-endings of hearing in the ear, is due to the vibration of some portion of matter, such as a tuning-fork, a bell, and so on.

Sounds are divided into two classes -- noises and musical notes. It may be shown by direct experiment that a noise is due to the irregular, interrupted vibration of a portion of matter, such as the tearing of a piece of paper or the rattling of a cart-wheel over cobble stones. On the other hand, a musical note can be proved to be due to a regular, uninterrupted vibration of a portion of matter, such as that obtained from a stretched string or tuning-fork. The presence between the ear of the observer and the vibrating instrument of some form of matter, such as air, water, or a solid body, is essential for the production of sound sensation. To analyse, therefore, different sounds, it is necessary to study different kinds of vibrations and the effect of these vibrations on surrounding matter. It may be shown that the most general possible vibration of matter is what is called a complex one. That is, it may be regarded as the superposition of an indefinite number of simple harmonic vibrations, such as those of simple pendulums. To completely understand, therefore, the nature of a complex vibration, it is necessary to know the component simple vibrations, then to determine the amplitude and the frequency of each of these components, and finally to observe the difference in phase of the component vibrations. As the result of the vibration of any portion of matter, such as a tuning-fork or a bell, there will be, in general, waves produced in the surrounding medium -- air, or whatever gas is present. This is true provided the rate of vibration of the body is sufficiently rapid; otherwise the air or gas will not be compressed, but will flow round the matter as it vibrates. If, however, the vibration exceeds a certain number in frequency, there will be compressional waves produced in the surrounding matter, and these will spread away with a velocity which is characteristic of the medium itself, and which is independent of the frequency of the vibration.

A simple harmonic vibration will produce a simple harmonic wave, the amplitude of the wave varying directly as the amplitude of the vibration. A complex vibration will, on the other hand, produce a complex wave, which can be analysed into simple harmonic waves in the same manner as a complex vibration can be. The waves will have different forms, depending not alone on the component vibrations, but also on their phases. These waves are propagated through a medium from the vibrating body, and in case they reach the ear of a hearing individual, a sound sensation is in general produced. Individuals differ, however, in their range of hearing, so it may happen that the frequency of the vibration has given rise to waves which are either too short or too long to affect the sense of hearing of the individual.

Corresponding to the peculiarity of the waves which reach the ear, it is to be expected that there will be differences in the sounds heard. Musical notes are distinguished by being either complex or simple, and it may be shown by experiment that a simple note is in every case due to a simple vibration; that a complex note is due to a complex vibration, it being noted, however, that differences in phase of the component vibrations, and therefore of the component waves, do not affect the character of the sound heard. The complexity of a given note seems to depend simply on the nature of the component vibrations, and not on their relative phases. A complex note is therefore to be regarded as a complex sensation due to a simultaneous production of simple notes. Simple notes differ among themselves in intensity or loudness, and in pitch or shrillness. It is found by experiment that the greater the amplitude of the original vibration, the louder is the sound; while the greater the frequency of the vibration, the higher is the pitch. Two vibrations which have the same frequency will in general produce two sounds of the same pitch. If, however, one of the vibrating bodies is approaching the ear or receding from it, the pitch of the sound produced by it is altered. This is known as Doppler's principle. It is shown by theory and verified by experiment that if the vibrating body is approaching the ear, or if the hearing individual is approaching the vibrating body, the pitch of the note is raised, whereas the contrary is true if the motions of the vibrating body and the hearing individual are reversed -- more vibrations reaching the ear in the one case and less in the other, than if the body is not approached.

In general, of course, the medium separating the vibrating body from the ear is air, and in this medium compressional waves travel at a rate which is found by experiment to be very nearly 332 metres per second at a temperature of 0^o Centigrade. At higher temperatures the velocity increases. These waves in the air obey the laws common to all wave motions. They can be reflected by large obstacles, thus causing echoes and giving rise to the phenomena of whispering galleries, and so on. They can be refracted, diffracted, and can be made to interfere in the same manner as waves in the ether.

Literature: textbooks of physics; POYNTING and THOMSON, Sound; HELMHOLTZ, Sensations of Tone (Eng. trans., Ellis); RAYLEIGH, Theory of Sound; PREYER, Ueber die Grenzen d. Tonwahrnehmung (1876); Ak. Untersuch. (1879); HÖFLER, Psychologie (1897), 95 ff.; DROBISCH, Ueber d. musikalische Tonbestimmung und Temp., Abhandl. d. k. sächs. Gesell. d. Wiss., ii. (1855) 35 ff.; VOLKMANN, Lehrb. d. Psychol., § 38; BEZOLD, Ueber die functionelle Prüfung d. menschl. Gehörorgans (1897); Das Hörvermögen d. Taubstrummen (1896); MELDE, MAYER, STUMPF, Wiedemann's Annalen (1898); SCHÄFER, Zeitsch. f. Psychol. (1899); ABRAHAM and BRÜIIL, Zeitsch. f. Psychol. (1898); EXNER, Pflüger's Arch., xiii; AUERBACH, Wiedemann's Annalen, vi; KOHLRAUSCH, ibid., x (1880); PFAUNDLER, Sitzber. d. Wien. Akad., ii (1877); BRÜCKE, ibid. (1884); MACH, Lotos (1873); APPUNN, Ueber Wahrnehmung tiefer Töne (1889); HERBART, Ueber d. Tonlehre, Werke, vii. 224 ff.; LUFT, Philos. Stud., iv; SCHISCHMANOW, ibid., v; LORENZ, ibid., vi; MARTIUS, ibid., vi; SCHULZE, ibid., xiv; MÜNSTERBERG, Beiträge, iv; KÖNIG, Quelques expériences d'acoustique (1882); MAYER, Amer. J. of Sci. (1874), viii; Philos. Mag., x1ix; SCHWARTZE, Handb. d. Ohrenh., i; BARTH, Zeitsch. f. Ohrenh. (1887), xvii; WIEN, Wiedemann's Annalen, xxxvi; ZWAARDEMAKER, Zeitsch. f. Psychol., vii; MEYER, ibid., xi. (J.S.A.)

III. AUDITORY (or HEARING) SENSATION: Ger. Gehörsempfindung; Fr. sensation auditive; Ital. sensazione uditiva. Auditory sensations fall into two great groups: sensations of tone and sensations of noise. In actual experience, the two are combined in the most various ways, though not so constantly as are the visual sensations of colour-tone and brightness. The stimulus to the sensation of noise is a single aperiodic movement -- a shock -- of the air particles; or, if this movement be physically impossible, a small number of wave movements, of which all but a very few are exceedingly weak. The stimulus for tone is a simple periodic vibratory movement of the air particles, continued for a certain length of time. The physical limit between noise and tone lies at about two complete vibrations; that between noise and a tone recognized as of a determinate pitch at five to sixteen vibrations.

The discrimination of tone is best in the middle region of the musical scale, decreasing above and below. Külpe has estimated the total number of discriminable tones at 11,000 that of simple noises -- though this latter estimate is very uncertain -- at 600. The limits of tonal hearing are usually set at 16 and 50,000 vibrations per second; but the position of the upper boundary must, in the light of recent work, be very considerably lowered. MUSIC (q.v.) employs less than 100 tones; and the reasons for the selection of these constitute an important psychological problem.

Tones form a one-dimensional manifold, which can hardly be represented in a geometrical figure. A straight line does justice to the continuity of the scale, but not to the degrees of FUSION (q.v.) of its terms. A spiral figure used by Drobisch shows the relation of each fundamental to its octave, but suggests that the approximation is gradual and constant, which is not the case.

The following theories of auditory sensation have more or less currency: --

(1) The Helmholtz-Hensen Theory. The cross-strings of the basilar membrane function as a series of resonators -- or the backboard of a piano. Each string is specifically tuned to a single wave-movement of the air particles, though it may vibrate weakly to neighbouring vibration-rates. Beats arise when the fibres intermediate between those of the two primary tones are thrown into interfering vibratory movements, and can occur only 'when the two exciting tones lie near enough to the prime tone of the sympathetic body for the latter to be set into sensible sympathetic vibration to both the tones used.' Combination tones are the result of the asymmetrical oscillations of the drum and ossicles of the ear. Noise sensations are set up through the basilar membrane, as tones are, by their own stimulus. The general theory has been confirmed by the proof of partial tone-deafness, i.e. deafness to a portion or portions of the musical scale. See TONE ISLANDS.

(2) The Rutherford-Waller Theory. This may be called the 'telephone,' as Helmholtz' is the 'piano theory.' The basilar membrane is set swinging by every stimulus, though more in some parts than in others, and thus gives 'acoustic pressure patterns' between the tectoria and the subjacent field of cell-hairs. The cells transmit the stimulation unanalysed to the brain, as the telephone transmits the sound of the voice.

(3) Ebbinghaus' modification of Helmholtz' theory affords a simpler explanation of beats and combination tones. In the first place, a tone sensation corresponds to the vibration of a number of basilar strings; the SPECIFIC ENERGY (q.v.) of each string -- the Helmholtz doctrine of one string for each tone -- is, in so far, given up. Secondly, every air wave sets in motion not only its own string but also, by the formation of nodes, other strings that are tuned to its harmonics. These assumptions enable Ebbinghaus to relate beats to combination tones, and to explain the relative intensity of the latter.

Noteworthy are further: (i) Wundt's theory of a direct oscillatory stimulation of the acoustic nerve (Physiol. Psychol., 4th ed., i. 478); (ii) Mach's theory of two specific energies (Analyse d. Empfindungen, 121); (iii) Hermann's and König's critiques of Helmholtz (Hermann, Pflüger's Arch., x1ix, 1vi; König, Quelques expériences d'acoustique, chap. ix); (iv) Meyer's sketch of a new theory (Zeitsch. f. Psychol., 1897; Beitr. z. Ak. u. Musikwiss., 1898; Pflüger'sArch., 1899); also citations under BEATS; (v) Stumpf's assumption of a specific noise energy, and doctrine of (simple) tone colour (Tonpsychologie, ii).

For special definitions see TIMBRE, NOISE, TONE, PITCH, INTERVAL, BEATS, and COMBINATION TONE.

Literature: EBBINGHAUS, Psychologie, 313; HELMHOLTZ, Sensations of Tone, 145; WALLER, Human Physiol., 461; BLASERNA, Theory of Sound (Ital. original, 1875); STUMPF, Tonpsychologie, i, ii; HENSEN, in Hermann's Handb. d. Physiol., iii. 2; especially NOEL, art. Audition in Richet's Dict. de Physiol. (with extensive bibliography); also BIBLIOG. G, 2, u, and the authorities cited above. (E.B.T.)

Hearing (defects of): Ger. Hördefekte; Fr. défauts de l'ouïe (or auditifs); Ital. difetti dell' udito. Defects of hearing, like those of vision, consist in a deficient capacity to obtain the characteristic forms of distinction and information normally yielded by the sense. Cf. DEAFNESS AND THE DEAF.

The factors of auditory perception are fewer and simpler, and contain a smaller element of interpretation than do those of vision. The characteristic forms of information yielded by the sense of hearing are the presence of sounds, their direction, their loudness, their pitch, their quality, their duration, and the endless varieties and combinations of these, of which speech, music, and noises are composed. Any serious defect in the detection of sounds is called deafness, which may be partial or total. In partial deafness, sounds of low intensity are not heard, but those of greater intensity may be distinctly perceived. If the sound is of constant loudness, its intensity will vary in an inverse ratio with the distance from the ear. To illustrate by a common test: if a watch which can be heard by the normal ear at 36 inches was heard by a defective ear only at 12 inches, the hearing power would be said to be 12 : 36 or 1 : 3. Cf. TESTS (psychophysical). Tests of the ability to distinguish between sounds of different intensity show a considerable variation in different individuals, some of whom undoubtedly possess a subnormal amount of such discriminative sensibility. In regard to defects of pitch, cases occur in which the ear, while deaf to sounds of certain pitches, is sensitive to lower or higher ones. This condition is termed TONE DEAFNESS (q.v.), or asonia. The range of pitch-hearing may be tested with regard to the highest audible tones by a Galton's whistle or by a set of steel bars, and for lowest tones by Appunn's forks. Tones which are audible to some ears are quite beyond the range for others; some persons fail to hear the chirp of a cricket, or the squeak of a mouse.

Similarly, there is a great variation among individuals in regard to the ability to appreciate musical effects and distinctions (largely a matter of pitch, interval, and quality). A considerable number are non-musical, or defective in musical hearing; but these distinctions, like most qualitative changes, are incapable of accurate determination. Cf. AMUSIA. Difficulties in the determination of the direction of sounds have been noticed, and have been traced to diseases which affect one ear alone, or the two ears unequally.

There are conditions of exalted or exaggerated hearing (hyperchusis or hyperaesthesia acustica) in which tones and noises produce more than their usual effect, owing to an irritable or sensitive condition of the nervous system; as in fevers, brain disease, &c. Of anomalous forms of hearing may be mentioned the subjective pulsating sounds, termed tinnitus; a double hearing in which each sound seems to be heard twice; paradoxical hearing in which hearing is better when a considerable noise (as in a railway train) is present; and several forms of subjective hearing. Hearing may take place not only through the normal conducting mechanism from the tympanum to the acoustic nerve, but indirectly through the skull; such conduction by the bones is of importance in the diagnosis of the nature of auditory defect.

Literature: GRUBER, Diseases of the Ear (Eng. trans.; 2nd ed., 1893); BUCK, Diseases of the Ear (3rd ed., 1898); LOVE and ADDISON, Deaf-Mutism (1896), chap. ii; citations made above, and under DEAFNESS. (J.J.)

Heart [AS. heorte]: Ger. Herz; Fr. coeur; Ital. cuore. A hollow muscular organ, in the path of blood or lymphatic vessels, whose rhythmic contractions, beats, furnish the initial motive force for movement of blood or lymph. Hearts may be simple, tubular or saccular, or chambered. (C.F.H.)

Heat and Cold Sensations: see TEMPERATURE SENSATION.

Heat Spot: Ger. Wärmepunkt; Fr. point chaud; Ital. punto termico di calore. See TEMPERATURE
 SPOT.

Heathen [Gr. eqnoV, a body of men, tribe, nation]: Ger. Heide; Fr. païen; Ital. pagano. To the Jews: those who had no knowledge of the true God.

Just as among the Greeks a distinction gradually grew up between Greeks and barbarians, so amongst the Hebrews a similar contrast developed between the Jews and the 'nations' (Goiim). While the former contrast was based on the idea that the Greeks alone enjoyed the opportunities amid which a truly human life could be led, the latter depended upon a religious difference. The heathen were those who had no knowledge of the true God. This contrast naturally and inevitably passed over into Christianity; and although Christianity broke down the racial exclusiveness of the Jews, yet, as the Church grew up, a similar attitude towards the heathen was produced. As a matter of fact, on a true interpretation of Christianity, the contrast is, not of race, but of inner spirit, of ethical attitude. But the tendency to look down upon non-Christians, and even to persecute them -- a tendency wholly at variance with the Christian spirit -- has never been overcome altogether.

In modern scientific investigations of the history of religions, the word heathen, when it is employed, is commonly used to indicate a very low form of religion, something that can be called religion only by an extension of the term which it is difficult to warrant.

Literature: see RELIGION (evolution of). (R.M.W.)

Heaven [etymology uncertain: possibly Lat. camera, a chamber, or capere, to hold]: Ger. Himmel; Fr. ciel (cieux); Ital. cielo. Strictly, the abode of God; the place whence Christ came, and to which he returned; the place prepared for the saved.

For philosophy it has no prominent interest, for it connects God with a definite locality, and is therefore a concession to that anthropomorphism which falls to be considered rather by history and science of religions than by philosophy. It ought to be added that many of the theological conjectures on the subject are without warrant in Scripture; and naturally so, for the matter offers free play equally to mystic spiritualism and to gross realism. See ESCHATOLOGY.

Literature: SALMOND, in Hastings' Dict. of the Bible; DORNER, Hist. of Christ. Doctrine (Eng. trans.), iv. 415 f., both giving full literature. (R.M.W.)

Hedonic (1) and Hedonics (2) [Gr. hdonh, pleasure]: Ger. Lust- und Unlust-bringend (1), Lust- Unlust-lehre (2); Fr. agréable ou pénible (1), théorie de la sensibilité (2); Ital. edonico (1), edonologia (suggested -- E.M.) (2). (1) Having pleasurable or painful colouring. (2) The science of pleasurable and painful conditions of consciousness.

Although by derivation hedonic refers to pleasure only, its use for both pleasurable and painful states is now well established. It is, therefore, not necessary to adopt algedonic and algedonics for this twofold reference, as Marshall (Pain, Pleasure, and Aesthetics, 9) suggests, seeing that pleasurable sufficiently well covers the narrower meaning of hedonic.

The science of hedonics treats of the nature of pleasurable and painful states of mind, their variations and development, their causes and effects, both mental and physical, &c.

Literature: see PAIN AND PLEASURE. (J.M.B., G.F.S.)

Hedonic Tone: Ger. Lust und Unlust; Fr. plaisir et peine, élément hédonique (suggested); Ital. elemento edonistico. The colouring of pleasure or pain attaching to a state of mind of any kind. See the recommendation made under AFFECTIVE TONE.

Following the broad connotation of hedonic as covering both pleasure and pain, hedonic tone serves as a substantive to that adjective. It is better than feeling tone, suggested by Stout, seeing that has the meaning given it by Wundt (translation of Gefühlston). See AFFECTIVE TONE. It is also better than algedonic tone, for the same reason that hedonic and hedonics are better than algedonic and algedonics (Marshall). There is a tendency to abbreviate the phrase into 'tone' and 'toned,' as 'tone of sensation' (Baldwin), 'pleasurably toned' (Stout), but that may lead to confusion with affective tone, and should not be done. The objection to the compound term pleasure-pain (Marshall) is that it does not allow the distinction between hedonic tone and the sensations of pleasure and pain, which many psychologists insist upon. See also PAIN AND PLEASURE, and FEELING. In French élément affectif is often used, but it fails, as 'affective element' fails in English, to mark the distinction between feeling tone and hedonic tone; and we recommend that it be reserved for the former.

Literature: STOUT, Analytic Psychol., i. 121 f.; MARSHALL, Pain, Pleasure, and Aesthetics, chap. i; BALDWIN, Handb. of Psychol., Senses and Intellect, 114; Feeling and Will, chap. v; and the citations under the terms referred to. (J.M.B., G.F.S.)

Hedonism: Ger. Hedonismus; Fr. hédonisme; Ital. edonismo. The theory that pleasure is the ultimate standard (or constituent) of moral value. See ETHICAL THEORIES, and EUDAEMONISM. (W.R.S.)