Imagination defined. -- Imagination may be defined as the faculty of forming mental images or representations of material objects, apart from the presence of the latter. The representation so formed is called in nearly all recent psychological literature an idea. This application of a term, which in the old philosophies invariably expressed the universal representations of the intellect, is unfortunate; but it has become so general that there is little hope of restoring the word to its ancient and proper signification. Accordingly, to avoid confusion, when employing the word idea to denote the general concept or notion, we will add the epithet intellectual to mark its supra-sensuous character. The term phantasm, by which the schoolmen, expressed very concisely the acts of the imagination, has been employed in the same sense by Dr. M'Cosh, and occasionally also by Hamilton and Dr. Porter, and we will use it along with the word image to denote this sensuous representation.
Ideas and Impressions. -- The idea or phantasm of the imagination differs in several respects from the percept, presentation, or impression, that is the act by which we perceive a real or present object, such, for instance, as a house. The idea is almost invariably very faint in intensity as compared with the impression. The outlines of the one are obscure and its constituent parts confusedly presented, while the other is realized in a clear and distinct manner. Still more striking is the contrast between the unsteady transitory character of the representation and the permanent stability of the perceived object. The image, too, is normally subject to our control, and can be annihilated by an act of will; the sensation, on the contrary, so long as the sense is exposed to the action of the object, is independent of us. The imagination, moreover, may vary the position of its object, and our own movements do not force us to leave behind us the idea. With the percept of the external sense it is otherwise; every change in our situation produces an alteration in its appearance. Depending on these lesser differences is the distinction most noted of all, the reference to objective reality, the belief in external independent existence which accompanies the act of sense-perception but is absent from that of the imagination. And yet, as St. Thomas pointed out long ago,{1} ideas are confounded with real objects, if not corrected by actual perception or free exercise of intellect.
Scholastic Doctrine. -- The Phantasy or Imagination was classed as an internal sense by the philosophers of the Peripatetic school. This view was based on the facts that the imagination operates by means of a physical organ -- the brain; that it represents particular concrete objects; and that these have only an internal or subjective existence. It was accordingly defined to be an internal power of the sensuous order. It was distinguished from the sensus communis, by the circumstance that while the function of that faculty was held to be the apprehension and distinction of the actual operations of the several senses, and of the qualities of objects hic et nunc perceived by them, the imagination forms representations or images of objects even in their absence. Modern writers commonly describe this aptitude of the mind as an intellectual power, but that this opinion is erroneous will become evident later on.
Productive and Reproductive Imagination. -- Several forms of the activity of the imagination have been allotted special names. The most commonly accepted division of the faculty is that into Reproductive and Productive Imagination. The former term is employed to designate the power of forming mental pictures of objects and events as they have been originally experienced, while the Productive Imagination signifies the power of constructing images of objects not previously perceived. The term Reproductive Imagination is used by some writers to denote the faculty of memory in general. This usage is objectionable. The differentia of memory is not reproduction, but recognition. All imagination, as we urge above, is essentially reproductive. The chief features in which remembrance differs from mere revival of images are: (1) The freedom of the imagination as to the number and variety of its acts, the limited character of our recollections; (2) the casual and variable order of the former states the serial fixity and regularity of the latter; (3) the isolated nature of imaginary events, the solidarity or relatedness of remembered occurrences, which are inextricably interwoven with multitudes of other representations; (4) finally, the peculiar reference to my own actual experience involved in the act of identification or recognition, which forms part of the recollection but is absent from the creations of fancy.
The spontaneous action of the faculty is sometimes called the passive imagination as contrasted with the active or voluntary exercise of its powers.{2} The epithets constructive and creative, are frequently applied to Productive Imagination, especially when the product is of a noble or beautiful kind. Strictly speaking, however, the imagination does not create of produce anything completely new; it merely combines into novel forms elements given in past sensations. These fresh combinations are effected under the guidance of will and judgment, and accordingly Hamilton has styled this attitude, the "Comparative Imagination," and the "Faculty of Relations." It has also been asserted that its range is not limited to objects of sense. This view is gravely erroneous. The scope of imagination is rigidly confined to the reproduction of former data of sense, and the congenital absence of any faculty correspondingly limits the field of the phantasy. The imagination, moreover, should not any more than external sense be called a faculty of relations, since both alike are equally incapable of apprehending such supra-sensuous realities. It is the intellect which in one case as in the other perceives abstract relations, and it is as serious an error to confuse rational activity with the power of forming sensuous images as with the capability of experiencing sensations.
Functions of the Imagination. -- The Imagination plays an important part in artistic and mechanical construction and in the more concrete branches of physical science. In all forms, however, of constructive imagination the three factors, purpose, attention, and discriminative selection co-operate. There must be at least in dim outlines before the mind an aim or object to be realized. Then, as in order to satisfy this vague desire the spontaneous activity of the faculty brings forward its materials, the attention is fixed on those likely to fit in to the wished-for ideal. Finally, selective discrimination retains those judged to he appropriate and rejects the remainder.
AEsthetic Imagination. -- In the creation of works of art the fancy of the poet, painter, sculptor, or musician, is employed in grouping and combining his materials so as to awaken admiration and satisfaction in the mind. At times his aim will be to hold the mirror up to nature, in order to delight by the exquisite skill and fidelity with which he reproduces an actual experience recalled by the memory. At other times he assumes a nobler part, and seeks to give expression to some thought embodying an ideal type of beauty or excellence, which is never met with in the commonplace world of real life, but is dimly shadowed forth in rare moments by our own imagination. The Beautiful is indeed the proper aim of the aesthetic fancy, as that of the scientific imagination is the True, and so discriminative selection directs the attention towards those elements which when combined will result in an Ideal. This function of the Imagination is called Idealization. Intellectual and volitional activity, however, are involved in such operations. The ideals formed may be artistic, scientific, ethical, or religious. Analysis of past experience and synthetic recombination of the elements constitute the essential stages of the process in each department. Both operations involve attention, abstraction, and comparison, so that the highest powers of the soul are employed in this exercise.{3} This faculty is said to be rich, fertile, or luxuriant when images of great variety issue forth in spontaneous abundance. Taste, on the other hand, implies judicious or refined, rather than luxuriant fancy. Great genius in any of the branches of art presupposes a fertile imagination, but true excellence is attained only when this power is controlled and directed by good judgment. The importance of Imagination in mechanical contrivance and invention is obvious. The power of holding firmly before the mind a clear and distinct representation of the object to be formed is one of the most necessary qualifications of constructive ability.
Scientific Imagination. -- The relations between imagination and science have been the subject of much dispute, some writers holding that a rich and powerful imagination is adverse rather than favourable to scientific excellence, while others consider this aptitude to be "as indispensable in the exact sciences as in the poetical and plastic arts." And that it may accordingly be reasonably doubted whether Aristotle or Homer were possessed of the more powerful imagination."{4}
Concrete Sciences. -- To answer the question we must distinguish different branches of science. In departments of concrete knowledge, such as geology, botany, animal physiology, and anatomy, the imagination is exercised almost as much as in history, oratory, or poetry; and even in astronomy and chemistry it plays an important part. The acquisition of information, and the extension of our command over any of the fields of physical nature involve careful use of our powers of external sense-perception; and progress is measured by the number and quality, the clearness and complexity, the readiness and precision of the ideas gathered. Fresh species, new properties, novel modes of action, must be more distinctly apprehended, more firmly retained, and more easily reproduced in imagination with every successive advance. The native efficiency of this faculty must, consequently, largely determine the rate of improvement and the limit of excellence attainable by each individual. In the region of original research, and especially in the construction of hypotbeses, fertility of imagination is an essential element of success; and the leading men in the history of these sciences have almost invariably been endowed with a bold and teeming fancy.
Scientific Hypotheses. -- Discoveries in Science, where they are not directly suggested by some lucky accident, generally start from hypotheses more or less erroneous which are gradually revised and corrected till they embrace all the facts. Scientific hypotheses differ from the guesses we are constantly making in all matters merely in the clearness with which they are conceived, and the rigour with which they are tested. All guesses involve exercise of the Imagination and so in proportion to the fertility of this faculty will be the mind's readiness in framing hypotheses of every kind. An efficient imagination contributes much to clearness and precision in the suppositions put forward by the intellect, and if well under control, it facilitates their retention in distinct consciousness and so renders them susceptible of searching examination. The great scientists, such as Newton and Kepler, have been even more remarkable for their rigorous severity in testing, than for their originality in inventing their hypotheses. But the accurate representation of possible causes and effects, the firm and distinct grasp of such conceptions, the anticipation of probable consequences, the comparison of diverse modes of action likely to happen under different contingencies, and the careful following out of trains of reasoning from conditional assumptions are all much facilitated by superior natural aptitude and judicious culture of the imagination.
According as man's memory is well stored with information in any branch of science, his fancy becomes fertile in picturing the action of unobserved causes and agencies, and in proportion as he is familiar with its subject-matter, his imagination will instinctively reject guesses likely to clash with known facts. A certain acquired sagacity controls and directs his conjectures along likely paths and lead him to detect those unobtrusive analogies which are the fruitful parent of so many great discoveries. Mr. Mark Baldwin thus writes: "The imagination is the prophetic forerunner of all great scientific discoveries. The mental factors seen to underlie all imaginative construction are here called into play in a highly exaggerated way. The associative material presented covers generally the whole area of the data of the scientific branch in hand; familiarity with the principles and laws already discovered is assumed and in general a condition of mental saturation with the subject. . . . In most cases the beginning of a discovery is nothing more than a conjecture, a happy supposition. The mind at once begins to search for means of testing it, which itself involves the imagination of new material dispositions. These tests are made more and more rigid, if successful, until the crucial test, as it is called, is reached, which either confirms or disproves the hypothesis."{5}
Abstract Sciences. -- When, however, we pass from the concrete to the more abstract branches of knowledge, such as pure mathematics, logic, and metaphysics, we find imagination sinks into a secondary position. The materials with which the mathematician or the metaphysician deals are not representations of phantasy, but of intellect. They are devoid of those impressive concrete qualities which distinguish the sensuous image from the abstractions of thought; and the chief difficulty of the beginner is to turn aside from the obtrusive features of the phantasm, and keep solely in view the delicate but vital relations which constitute the essence of scientific knowledge.
It seems to us, then, to be the very reverse of truth to say that imagination holds a place in abstract science similar to that which it occupies in poetry. As all thought is representative, the abstract thinker must, of course, be capable of forming representations of the subjects of his speculation; and the distinctive characteristic of genius in this direction lies in the power to grasp vigorously some fruitful notion and to concentrate upon it for long periods the whole energy of the mind. Still it is a grave error to confound the rational activity of the intellect with the operations of the sensuous imagination. And it should be borne in mind that although elastic and fertile powers of fancy often accompany great intellectual gifts, and although even in the abstract sciences discovery may be at times materially aided by the power of holding steadily before the mind concrete images; nevertheless it is the intellect and not the imagination that apprehends the universal relations which form the framework of science.
Dangers of Imagination. -- It is needless to point out how easily richness of imagination may prove detrimental rather than beneficial to scientific progress. In Ethics or Metaphysics, no less than in History or Biology, exuberant and prolific fancy when uncontrolled by reason, may divert attention from the essential to the accidental, may pervert and mislead the powers of judgment, and may so confuse the reason that fiction is substituted for objective reality, and brilliant poetic hypotheses are preferred to the prose of commonplace truth.
Fancy. -- The term Fancy is sometimes used to mark the activity of the imagination as exercised in the production of comic, or even of beautiful images, provided they be of a minute or trivial type. Fancy, too, is confined to the sphere of the unreal whilst imagination may represent the actual. The epithets merry, playful, weird, which are applied to the former, indicate the various kinds of action in which it manifests itself, and it is with that aptitude wit and humour are mainly connected.
Wit and Humour. -- Intellect, as well as imagination, is involved in the exhibition and appreciation of wit and humour, but the happy suggestions of the fancy are the essential materials which go to make up the amusing picture. Wit and humour agreeing in some respects are distinguished in others. Both aptitudes imply the power of noting and manifesting unexpected points of agreement between apparently disparate ideas; but wit excels in brilliancy and pungency. It is, too, of a more intellectual character, while humour appeals rather to the moral side of human nature. The witty man is quick to perceive incongruous associations of every kind, the humourist is a close observer of the foibles and weaknesses of his fellow-men. Humour is mainly innate, wit is to some extent amenable to education and culture. Humour, implying the power of sympathy with the feelings of others, is commonly associated with good nature, while wit is frequently sharp and unpleasant. This distinction is admirably expressed in Thackeray's saying that "Humour is wit tempered by love." The most degraded form of wit is exhibited in puns, where commonly there is merely an accidental similarity in oral sound. The felicitous apprehension of a hidden connexion between incongruous ideas, which constitutes the essence of true wit, is almost invariably absent.
Illusions. -- As the activity of Imagination is the chief source of certain abnormal mental phenomena of an important character described as illusions, hallucinations, dreams, and the like, this will be, perhaps, the most appropriate place to treat of them. In ordinary language the terms illusion, delusion, and fallacy are frequently used in the same sense to denote any erroneous conviction. In a more limited signification fallacy means a vicious reasoning, an intellectual inference of a fallacious character, whilst illusion signifies a deceptive or spurious act of apprehension, and delusion implies a false belief of a somewhat permanent nature, and of a more or less extensive range. These states of consciousness have in common the note of untruthfulness; and we may, from a psychological standpoint, define a mental act to be untrue, which disagrees from its object as that object is known by the normal human mind. An illusion is thus a deceptive cognition which pretends to be immediately evident, and it can refer to mistaken memories and erroneous expectations, just as well as to false perceptions of the external senses.{6}
Sources of Illusion. -- The causes of illusion we may in the first place roughly divide into two great classes, according as they belong to the subjective or the objective worlds. Our mistakes may arise either from mental influences, or from irregular conditions of the material universe, including among the latter the state of our own organism.
Mental influences. -- The wide range of the first group will become evident if we recall the various elements which we have shown in a previous chapter to be involved in apparently simple acts of sense-perception. The material directly presented to us, even by the power of vision, is extremely small. By far the greater part of the information given through each act of apprehension is due to memory, inference, and associated sensations of other faculties faintly revived in imagination. Accordingly, the condition of the mind immediately antecedent to the impression of any particular object has a most important influence in determining how this object will be perceived. If the imagination is vigorously excited, and if we have a lively expectation of beholding some special occurrence, there is a considerable probability that anything bearing even a distant resemblance to it will he mistaken for the anticipated experience. As the physical concomitants of the activity of the imagination are similar in kind to those of real sensation, and as even in normal perception a large part of the mental product is furnished by the phantasy from the resources of previous experiences, it is not surprising that where anticipation of an event is very strong, and its representation very vivid, the mind may perceive an occurrence before it happens, or apprehend an object where none exists. This species of deception, in which a mental state is excited without any external cause, is called a subjective sensation. Such simulated cognitions may work very serious effects on the organism. The pain or pleasure, according to the agreeable or disagreeable character of the illusion, may be fully as intense as if the appearance were a reality.{7}
In addition to expectation, desire, and fear, are the mental states which have the largest share in the production of illusion. The strength of the inclination to believe in that which we like, manifests itself in every department of human life. Yet, paradoxical as it may at first sight appear, dislike can also contribute to the generation of an illusory belief. The most important constituent in the emotion of fear is aversion, but it is a matter of frequent experience that a lively fear of anything tends to create in the mind a counterfeit perception of it. The timid wayfarer, travelling by night, sees a highwayman in every gatepost, whilst the child who has just been listening to ghost stories converts the furniture of his moonlit bed-room into fairies and hobgoblins. Inordinate anxiety generates all sorts of doubts and suspicions, and --
The mental process in the case of fear is, however, fundamentally akin to that of desire. The immediate effect of both sentiments is intense excitation of the imagination, a lively picture of the desired or dreaded event is conjured up by the fancy, and the vivid image is taken for the reality.
Other Influences. -- The second group of causes of illusion, which may be roughly described as nonmental, are subdivided according as the deception is due, (a) to ill-health either of the particular organ employed, or of the brain and nervous system as a whole, or (b) to some irregularity in the composition of the medium intervening between the organism and the object apprehended.
(a) Organic. -- The forms of illusion which may arise from an unsound condition of the organ are very numerous. A sense may be subject to permanent defects such as partial deafness, short-sightedness, and colour-blindness, or it may suffer transient disabilities such as fatigue, disarrangement, and temporary disease of the nerves employed in a particular perception. After steadily gazing at a small disc of a brilliant colour, the eye will see a similar spot of a complementary hue if directed immediately afterwards towards a plain white surface. Intense stimulation of any of the senses renders it for a time insensible to lesser excitations. Santonin induces colour-blindness to violet, and other drugs deaden other modes of sensibility. The disease of jaundice sometimes gives things a yellow tinge. In certain cerebral and nervous diseases illusions often take a more pronounced and extreme form, and the mind may not only misapprehend real things, but it may even become incapable of distinguishing between actual objects and pure phantoms of the imagination. An aberration of this extreme and permanent kind is commonly termed a hallucination. The passenger who, in a London fog, mistakes a lamp-post for a policeman, is said to be under an illusion. The fever-patient who sees his empty room crowded with people, and the lunatic who believes he is the Emperor of China, are possessed by hallucinations. The passage, however, from the one state to the other is gradual, and there is no rigid line of demarcation separating them. The cause of these aberrations seems to lie in the abnormal working of the interior physical processes which usually give rise to sensations, or which have accompanied particular cognitions in the past, and so cause these latter to be reproduced from memory with such vividness as to be confounded with real impressions. The illusions of delirium tremens, and of many forms of mental derangement, are probably caused by mistaking internal irritation of the nerves for external natural sensations. And complete lunacy may arise either from disorder of the functions of the cerebrum, caused by the presence of poisonous materials in the blood, or from some organic disease which has already seized on the substance of the brain.
(b) External. -- The deceptions originated by irregular conditions of the environment are very familiar. If we gaze at the sun through a piece of red or green glass, only rays of these colours will be allowed to pass, and its disc will appear of a corresponding hue. A dull wintry landscape observed through a transparent substance of a slightly yellow tint assumes a golden autumnal appearance. The magic effects of the transformation scene at the pantomime are the result of the skilful management of coloured lights, and spectral apparitions are commonly produced by the manipulation of concave mirrors at the sides of the stage. In operations of this nature, however, the sense is perfectly truthful as regards its own revelations. It responds in an appropriate manner to its proximate stimuli, and the error due to the abnormal relations between the latter and the remote object which they ordinarily present to the mind.
Illusion in the strictest sense of the term comes into existence when we pass from the immediate data of the senses to their indirect or acquired perceptions. Here, when the customary character of the environment is changed, the imagination excited through past association may induce complete deception. Our estimate of distance and magnitude may thus be altogether invalidated. A figure seen through a fog is enlarged because the vagueness of its outlines causes us to exaggerate its distance. The perspective appearance of landscape paintings and of stereoscopic pictures, as well as the ingenious contrivances to which the diorama owes its success, are designed to awaken through the imagination by means of the laws of suggestion an illusory belief as regards the spatial relations of the several parts of the perceived object. Akin to this class of illusions are some others due to the unusual presence or absence of materials for comparison. The empty rooms of a house in the process of building always look smaller than they really are, because we have not the customary furniture to call our attention to the capacity of the space. Similarly, a disproportionately large table diminishes the size of a chamber. On the other hand, a multiplicity of small objects magnifies a given amount of space. A field with hay-cocks scattered over it, a harbour with ships, or an orchard studded with apple-trees, seems far larger than the same space when empty. The other senses are subject to analogous mistakes. The illusion produced by an echo is similar to that of the looking-glass. In a rarified atmosphere the force of sound is lowered in a surprising degree. De Saussure judged the explosion of a pistol at the top of Mont Blanc to be about equal to that of a common cracker below. Want of homogeneity, moreover, in the intervening medium can interrupt, reflect, or change the character of sound just as of light.
Dreaming and Reverie. -- A specially interesting form of illusion, or rather hallucination, is that exhibited in dreaming. Dreams are mental processes which take place during sleep, and are in some respects akin to states of reverie which occur during waking life. In dreaming the imagination assumes the part played in waking life by the external senses. During sleep the activity of these latter falls into almost complete abeyance; volitional control over the course of thought ceases; the power of reflexion and comparison is suspended; and the fancy of the dreamer moves along automatically under the guidance of association. Consideration of these circumstances will help us to partially account for the peculiar features of the dream. Its chief characteristics are, (a) its verisimilitude, (b) its incoherence and extravagance, (c) its possession of a certain coherence amid this inconsistency, and (d) the exaggeration of actual impressions.
(a) Verisimilitude. -- The apparent reality of the dream is, in great part, a consequence of the cessation of the action of the external senses. In sleep the images of the fancy which may arise within us are not subject to the correction which the presentations of the senses are ever furnishing during waking life. Even in the most profound reverie, when our thoughts move along at random, there is always, so long as we are awake, a plentiful stream of sensation flowing in upon the mind through the several faculties; and although we scarcely advert to them, these sensations exert a steady counteracting influence on the flights of fancy. The objects which we dimly see around us, the tactual and auditory impressions of which we are vaguely conscious, all conspire to keep us in constant collision with reality; and when we imagine ourselves at the head of an army, or in the jaws of a tiger, the obscurely apprehended table and chairs of our room exert a silent check upon the credence we are inclined to give to all vivid ideas. In sleep it is otherwise; the corrective action of the external senses being cut off, we are completely at the mercy of the phantasy, and place implicit confidence in each new illusory cognition.{8}
(b) Incoherence. -- The inconsistency of the dream seems to be due to its course being left entirely to the guidance of fortuitous associations modified by the interference of accidental sensations at the moment. The absence of voluntary attention or control over our thoughts disables us from reflecting upon the ideas which arise spontaneously, and prevents us from comparing them with past experience, or with each other. In reverie, on the contrary, this voluntary power rarely sinks into complete abeyance, and on the suggestion of some flagrant absurdity, the mind can exert itself against the illogical train of images, and even if it permits the incongruous series to take their course, at least reserves its assent. The casual entrance of the few external impressions which penetrate to the mind during sleep, and the actions of of the systemic sensations are probably fertile sources of new lines of thought. But since self-command no longer exists, although we may feel a vague surprise at the chaotic groupings of ideas thus effected, we are yet unable to elicit the reflective act by which the inconsistency may be brought home to us, and accordingly thought follows thought in an arbitrary manner.
(c) Coherence. -- The consistency of the dream, in so far as it occasionally exists, probably results in part from an orderly succession of previously associated ideas, in part from a faint power of selection exerted by a dominant tone of consciousness at the time, which rejects striking eccentricities.
(d) Exaggeration. -- The exaggeration of occasional real impressions is accounted for by the fact that while the great majority of external sensations are excluded, those which do find entrance are thereby in a peculiarly favourable position. They are in novel isolation from their surroundings; their nature is vaguely apprehended;{9} and they cannot be confronted with other experiences. Accordingly they usurp the whole available resources of consciousness, and so assume an utterly inordinate importance. A slight sensation of cold or pressure, if it accidentally fits in with the current of our dream, may thus give rise to the illusion that we are lost in a snow-storm, or crushed under a falling house. The seeming rapidity of events, which is simply the rapidity of thoughts confounded with reality, is explained in the same way.{10}
In brief, then, as following Aristotle, St. Thomas himself repeatedly teaches, the mind accepts the representations of the imagination as real objects unless it be checked by some other faculty; consequently when, as in sleep, the senses and the free application of the understanding which constitutes voluntary attention are suspended, illusion is inevitable.{11}
Readings. -- On the Imagination, cf. St. Thomas, Comm. De Anima, Lib. III. Lect. 4-6; Mark Baldwin, op. cit. c. xii; Carpenter, Mental Physiology, c. xii.; Hamilton, Metaph. Lect. xxxiii.; Porter, op. cit. Part. II. cc. v. vi.; Gutberlet, Die Psychologie, pp. 83, seq. On Illusions, cf. Farges, L'Objectivite de Ia Perception des Sens Externes, pp. 184-237; Baldwin, op. cit. c. xiii. The subject of Dreams is treated by Aristotle in a special tract, cf. St. Thomas, Comm. De Somniis. Carpenter, op. cit. c. xv. is good on the same subject.
{1} Qq. Disp. De Malo, III. a. 3, ad 9.
{2} Cf. Mark Baldwin, op. cit. p. 224.
{3} Cf. Dr. Porter, op. cit. §§ 353-372.
{4} Hamilton, Metaph. ii. p. 265.
{5} Senses and Intellect, pp. 236, 237. There are many valuable observations in his chapter on this subject.
{6} Cf. Mr. Sully's Illusions, cc. i. ii. Many of these phenomena are very skilfully analyzed by that writer.
{7} "A butcher was brought into the shop of Mr. Macfarlan, the druggist, from the market-place opposite, labouring under a terrible accident. The man on trying to hook up a heavy piece of meat above his head slipped and the sharp hook penetrated his arm so that he himself was suspended. On being examined he was pale. almost pulseless and expressed himself as suffering acute agony. The arm could not be moved without causing excessive pain, and in cutting off the sleeve he frequently cried out; yet when the arm was exposed it was found to be quite uninjured, the hook having only traversed the sleeve of his coat." (Carpenter, op. cii. p. 158.)
{8} Lewes, following Hartley, explains the apparent reality of the phantasms of the dream, mainly by the suspension of the corrective action of the external senses. Cf. Physiology of Common Life, pp. 367-370. Carpenter, Mental Physiology, § 482, in accordance with the important part he assigns to Will in mental life, like Stewart, lays chief stress on "the entire suspension of volitional control over the current of thought" during sleep. St. Thomas had anticipated both explanations. He accounts for the illusions of sleep by the suspension of the senses combined with the interruption of the voluntary control of reason. See note on next page.
{9} Mr. Sully (Illusions, pp. 147-149) ascribes the magnifying agency of the dream chiefly to the obscure manner in which the nature of the stimulus is apprehended -- ignotum pro magnifico. The force of a novel impression even in waking life is usually overestimated. In sleep the general lethargy of the higher centres engaged in cognition prevents proper recognition of even familiar stimuli, and so converts them into strange or formidable phenomena.
{10} "The only phase of the waking state in which any such intensely rapid soccession of thoughts presents itself, is that which is now well attested as a frequent occurrence, under circumstances in which there is imminent danger of death, especially by drowning, the whole previous life of the individual seems to he presented instantaneously to his view, with its every important incident vividly impressed on his consciousness, just as if all were combined in a picture, the whole of which could be taken in at a glance." (Carpenter, op. cit. § 484, note.)
{11} "Quod rerum species vel similitudines non discernantur a rebus ipsis, contingit ex hoc quod vis altior, quae judicare et discernere potest, ligatur. . . . Sic ergo cum offeruntur imaginariae similitudines. inhaeretur eis quasi rebus ipsis, nisi sit aliqua alia vis quae contradicat, puta sensus aut ratio. Si autem sit ligata ratio, et sensus sopitus, inhaeretur similitudinibus sicut ipsis rebus, ut in visiis dormientium accidit, et ita in phreneticis." (Qq. Disp. De Malo, III. a. 3. ad 9. Cf. Comment, in Arist., De Somniis, Lect. iv.)