1. Associations in all their forms are regarded by us as passive experiences, because the feeling of activity, which is characteristic of all processes of volition and attention, never arises except as it is added to the already completed association process in a kind of apperception of the resultant, given content (p. 244). Associations are, accordingly, processes which can arouse volitions but are not themselves directly influenced by volitions. This absence of any dependence on volition is, however, the criterion of a passive process.

The case is essentially different with the second kind of combinations which are formed between different psychical compounds and their elements, namely, the apperceptive combinations. Here the feeling of activity with its accompanying variable sensations of tension does not merely follow the combinations as an after-effect produced by them, but it precedes them so that the combinations themselves are immediately recognized as formed with the aid of the attention. In this sense these experiences are called active experiences.

2. Apperceptive combinations include a large number of psychical processes which are distinguished in popular parlance under the general terms thinking, reflection, imagination, and understanding. These are all regarded as psychical processes of a type higher than sense perceptions or pure memory processes, while at the same time they are all looked upon as different from one another. Especially is this true of the so-called functions of imagination and understanding. In contrast with this loose view of the faculty theory, association psychology sought to find a unitary principle by subsuming also the apperceptive combinations of ideas under the general concept of association, and at the same time limiting the concept, as noted above (p. 251), to successive association. This reduction to successive association was effected either by neglecting the essential subjective and objective distinguishing marks of apperceptive combinations, or by attempting to avoid the difficulties of an explanation, through the introduction of certain supplementary concepts taken from popular psychology. Thus, "interest" and "intelligence" were credited with an influence on associations. Very often this view was based on the erroneous notion that the recognition of certain distinguishing features in apperceptive combinations and associations meant the assertion of a fundamental division between the former and the latter. Of course, this is not true. All psychical processes are connected with associations as much as with the original sense

perceptions. Yet, just as associations always form a part of every sense perception and in spite of that appear in memory processes as relatively independent processes, so apperceptive combinations are based always on associations, but the essential attributes of these apperceptive combinations are not traceable to associations.

3. In trying to account for the essential attributes of apperceptive combinations, we may divide the psychical processes which belong to this class into simple and complex apperceptive functions. The simple functions are those of relating and comparing, the complex those of synthesis and analysis.

So long as the recognition remains a pure association, the process of relating is limited to the feeling of familiarity which follows the assimilation of the new impression either immediately, or after a short interval. When, on the contrary, apperception is added to association, this feeling is supplied with a clearly recognized ideational substratum. The earlier perception and the new impression are separated in time and then brought into a relation of agreement on the basis of their essential attributes. The case is similar when we become conscious of the motives of a memory act. This also presupposes that a comparison of the memory image with the impression which occasioned it, is added to the merely associative process which gave rise to the image. This, it will be seen, is a process that can be brought about only through attention.

5. Thus, the relating function is brought into activity through associations, wherever these associations themselves or their products are made the objects of voluntary observation. The relating function is connected, as the examples mentioned show, with the function of comparing, whenever the related contents of consciousness are clearly separated processes, belonging to one and the same class of psychical experiences. Relating activity is, therefore, the wider concept, comparison is the narrower. A comparison is possible only when the compared contents are brought into relation with one another. On the other hand, conscious contents may be related without being compared with one another, as is the case, for example, when an attribute is related to its object, or when one process is related to another which regularly follows or precedes it. As a result of this it follows that where the fuller conditions necessary for a comparison are present, the experiences given may be merely related, or they may also be compared with each other. Thus, one calls it relating when he thinks of a present impression as the reason for remembering an earlier experience; he calls it comparing, on the other hand, when he establishes certain definite points of agreement or difference between the earlier and the present impression.

6. The process of comparing is, in turn, made up of two elementary functions which are as a rule intimately interconnected. These two elementary functions are first, the perception of agreements, and second, the perception of differences. There is a mistaken view prevalent even in present-day psychology. It originated in popular psychology and was strengthened by the discussions of logical intellectualism. It consists in the acceptance of the notion that the mere existence of psychical elements and compounds is identical with their apperceptive comparison. Every sensation is accordingly treated as a "sensory judgment", every immediate perception of distance as a "judgment of depth", and so on through the whole series of processes. In all these cases, however, the judgment appears after the sensations and ideas;

the judgment must, therefore, be recognized as a separate process. To be sure, agreements and differences arise in our psychical processes, if they did not we could not observe them. But the comparing activity through which these likenesses and differences in sensations and ideas are made evident, is not identical with the sensations and ideas themselves. It is a function which may arise in connection with these elements, but does not necessarily so arise.

7. Even the psychical elements, that is, sensations and simple feelings, can be compared with reference to their agreements and differences. Indeed, it is through a series of such comparisons that we arrange these psychical elements into systems, each one of which contains the elements which are most closely related. Within a given system two kinds of comparison are possible, namely, comparison in respect to quality and comparison in respect to intensity. Then, too, a comparison between grades of clearness is possible when attention is paid to the way in which the elements appear in consciousness. In the same way comparison is applied to intensive and extensive psychical compounds. Every psychical element and every psychical compound, in so far as it is a member of a regular system, constitutes a psychical magnitude. A determination of the value of such a psychical magnitude is possible only through comparison with some other magnitude in the same system. Psychical magnitude is, accordingly, an original attribute of every psychical element and compound. It is of various kinds, as intensity, quality, extensive (spatial and temporal) value, and, when the different states of consciousness are considered, clearness. But the determination of psychical value can be effected only through the apperceptive function of comparison.

8. Psychical measurement differs from physical measurement in the fact that the latter may be carried out in acts of comparison separated almost indefinitely in time, because its objects are relatively constant. For example, we can determine the height of a certain mountain to-day with a barometer and then after a long time we may determine the height of another mountain, and if no sensible changes in the configuration of the land have taken place in the interval, we can compare the results of our two measurements. Psychical compounds, on the other hand, are not relatively permanent objects, but continually changing processes, so that we can compare two such psychical magnitudes only when other conditions remain the same, and when the two factors to be compared follow each other in immediate succession. These requirements have as their immediate corollaries: first, that there is no absolute standard for the comparison of psychical magnitudes, but every such comparison stands by itself and is of merely relative validity; second, that finer comparisons are possible only between psychical magnitudes of the same dimension, so that a reduction, analogous to that by which the most widely separate physical quantities, such as periods of time and physical forces, are all expressed in terms of one dimension of space, is out of the question in psychical comparisons.

9. It follows that the possible relations between psychical magnitudes which can be established by direct comparison are limited in number. The establishment of such relations is possible only in certain particularly favorable cases. These favorable cases are 1) the equality between two psychical magnitudes and 2) the just noticeable difference between two such magnitudes, as for example two sensation intensities of like quality, or two qualities of like intensity belonging to the same dimension. As a somewhat more complex case which still lies within the limits of immediate comparison we" have 3) the equality of two differences between magnitudes, especially when these magnitudes belong to neighboring parts of the same system. It is clear that in each of these three kinds of psychical measurements the two fundamental functions in apperceptive comparison, namely the perception of agreements and the perception of differences, are both applied together. In the first case, one of two psychical magnitudes, A and B, is gradually varied until it agrees for immediate comparison with the other; thus, for example, B is varied until it agrees with A. In the second case A and B are taken equal at first and then B is changed until it appears either just noticeably greater or just noticeably smaller than A. Finally, the third case is used to the greatest advantage when a whole line of psychical magnitudes, as for example of sensation intensities, extending from A as a lower limit to C as an upper limit, is so divided by a middle quantity B, which has been found by gradual variations, and is so placed that the partial distance AB is apperceived as equal to BC.

10. The most direct and most easily utilizable results derived from these methods of comparison are given by the second method, or the method of minimal differences as it is called. The difference between the physical stimuli which corresponds to the just noticeable difference between psychical magnitudes is called the difference threshold of the stimulus. The intensity at which the resulting psychical process, as for example a sensation, can be just apperceived, is called the stimulus threshold. Observation shows that the difference threshold of the stimulus increases in proportion to the distance from the stimulus threshold, in such a way that the relation between the difference threshold and the absolute quantity of the stimulus, or the relative difference threshold, remains constant. If, for example, a certain sound the intensity of which is 1 must be increased ¹/₃ in order that the sensation may be just noticeably greater, a sound whose intensity is 2 must be increased ²/₃, one with an intensity 3 must be increased ³/₃, etc., to reach the difference threshold. This law is called Weber's law, after its discoverer E. H. weber. It is easily understood when we look upon it as a law of apperceptive comparison. From this point of view it must obviously be interpreted to mean that psychical magnitudes can be compared only according to their relative values.

This view that weber's law is an expression of the general law of the relativity of psychical magnitudes, assumes that the psychical magnitudes which are compared, themselves increase within the limits of the validity of the law in direct proportion to their stimuli. It has not yet been possible to demonstrate the truth of this assumption on its physiological side, on account of the difficulties of measuring exactly the stimulation of nerves and sense-organs. Still, we have evidence in favor of it in the psychological fact that in certain special cases, where the conditions of observation lead very naturally to a comparison of absolute differences in magnitude, the absolute difference threshold, instead of the relative threshold, is found to be constant. We have such a case, for example, in the comparison, within wide limits, of minimaldifferences in pitch (p. 58). Then, too, where large differences in sensations are compared according to the third method described above (p. 290), it is found in general that equal absolute stimulus differences, not relative differences, are perceived as equal. This shows that apperceptive comparison follows two different principles under different conditions, a principle of relative comparison (weber's law) which is the more general, and a principle of absolute comparison which takes the place of the first principle under special conditions which favor such a form of apperception.

10a. Weber's law has been shown to hold, first of all, for the intensity of sensations and then, in a more limited way, for the comparison of extensive compounds, especially temporal ideas, and also, to some extent, for spatial ideas of sight and for motor ideas. On the other hand, it does not hold for the spatial ideas of external touch, obviously on account of the complexity of the local signs (p. 120); and it can not be verified for sensation qualities. The scale of tonal intervals is relative because every interval corresponds to a certain ratio between the number of vibrations (for example, an octave 1 : 2, a fifth 2 : 3, etc.). This is probably due to the relationship between clangs which is due to the relation of the fundamental tone to its overtones (comp. p. 108 sq.). Even when an absolute comparison takes place instead of a comparison according to weber's law of relativity, we must not confuse this with the establishment of an absolute measure. That would presuppose an absolute unit, that is, the possibility of finding a constant standard, which, as noted above (p. 289), is impossible in the psychical world. Absolute comparison must take the form of a recognition of the equality of equal absolute differences. This is possible in certain single cases without a constant unit. Thus, for example, we compare two sensation lines A B and B C according to their relative values, when we think in both cases of the relation of the upper to the lower extreme sensation. In such a case, accordingly, we judge A B and B C to be equal when  — (weber's law). On the other hand, we compare A B and B C according to their absolute values when the difference between C and B in the single sensation dimension in question appears equal to that between B and A, that is, when C — B = B — A (merkel's law). The recognition of quantitative or qualitative differences is rendered more difficult when the two stimuli to be compared are presented in continuous sequence, and with neither a time nor space interval separating them. The difference threshold is, accordingly, greater in such cases, and it grows still longer the more slowly the continuous transition from one stimulus to the other takes place. Thus, the threshold for brightness, when two distinct stimulations are compared with each other, is ¹/₁₀₀ (p. 63). When, on the other hand, the two stimuli are not separate, but the first passes very rapidly into the second, the threshold is ³/₁₀₀ and about ¹⁰/₁₀₀ if the transition is slow. The threshold for distinctly separated tones is ¹/₃ vibrations (p. 58); for continuous tonal changes ¹/₃ to 1¹/₂ vibrations. The threshold for distinctly separated pressures is ⁸/₁₀₀ (p. 53); for continuous changes ¹⁰/₁₀₀ to ³⁰/₁₀₀ the larger fraction represents the results of slow transitions. Even under the more difficult conditions of comparison described, weber's law holds true for those spheres of comparison to which it applies under any conditions.

By treating weber's law as an expression of the functional relation between sensation and stimulus and by assuming that the law is valid for infinitely small changes of both sensation and stimulus, fechner worked out the formula,  (R represents the stimulus and E the sensation). From this formula he derived as the formula for finite sensation values and stimuli the following logarithmic expression E = k. log R + c. That is, the sensation is proportional in its increase to the logarithm of the stimulus, c and k representing constants which must be determined by experiment (fechner's Psycho-physical Law). This formula, however, because of its assumption of an immediate relation between sensation and stimulus, fails to indicate the fact that in all probability the law depends upon the relation between the sensations measured. If we recognize the relation as one between the sensations, we may adopt the formula  represents the difference threshold, V the ratio of comparison. This formula contains nothing but psychical magnitudes thus conforming to the probable significance of weber's law.

10b. The methods for the demonstration of weber's law, or of other relations between psychical magnitudes, whether elementary or compound, are usually called psycho-physical methods. The name is unsuitable, however, because the fact that physical means are here employed is not unique, but holds for all the methods of experimental psychology. The methods could better be called "methods for the measurement of psychical magnitudes". With these methods it is possible to follow one of two courses in finding the relations mentioned as favorable for judgment. A first or direct mode of procedure is as follows: one of two psychical magnitudes A and B, as for example A, is kept constant, and B is gradually varied until it stands in one of the relations mentioned, that is, either equals A or is just noticeably greater or smaller. These are the adjustment methods. Among these we have as the method most frequently used and the one which leads most directly to conclusions, the "method of minimal changes", and as a kind of modification of this for the case of adjustment in which equality is the end sought, the "method of average error". The second mode of procedure is to compare in a large number of cases any two stimuli, A and B, which are very little different, and to compute from the number of cases in which the judgments are A = B, A > B, A < B, the position of the relations mentioned, especially the difference threshold. These are the calculation methods. The chief of these is the method known as that of "right and wrong cases". It would be more proper to call it the "method of three cases" (equality, positive difference, and negative difference). Details as to this and the other methods belong in a special treatise on experimental psychology.

There are two other interpretations of weber's law still met with besides the psychological interpretation given above, they may be called the physiological and the psycho-physical theories. The first derives the law from hypothetically assumed relations in the conduction of excitations in the central nervous system. The second regards the law as a specific law of the "interaction between body and mind". The physiological interpretation is entirely hypothetical and in certain cases, as for example in the case of temporal and spatial ideas, entirely inapplicable. The psycho-physical interpretation of fechner is based upon a view of the relation of mind which must be rejected by the psychology of to-day (cf. § 22, 8).

References. E. H. Weber, Tastsinn und Gemeingefühl, Handwörterb. d. Physiol., vol. III, Pt. 2. Fechner, Elemente der Psychophysik, 1860, and In Sachen der Psychophysik, 1877, and Revision der Hauptpunkte der Psychophysik, 1882 and Ueber die psychischen Maßprincipien, Phil. Stud., vol. 4, 1887. G. E. Müller, Zur Grundlegung der Psychophysik, 1878. Delboeuf, Elements de psycho-physique, 1883. G. F. Lipps, Grundriss der Psychophysik, 1899; Arch. f. Psych., vol. 3. Foucault, La Psychol-physique, 1901. Wundt, Phil. Stud., vols. 1 and 2, and Grundz., 5th ed., vol. I, chap. 9, vol. III, chap. 19; Lectures, lectures 2—4; Logik, vol. II, Pt. 2, chap. 2 (on the measurement of psychical magnitudes in general). Special Investigations: Merkel, Phil. Stud., vols. 4, 5, 7, 8 and 9. Tischer, Phil. Stud., vol. 1. Kraepelin, Phil. Stud., vol. 2. Angell, Phil. Stud., vol. 7. Kaempfe, Phil. Stud., vol. 8. On Comparison of Changes in Sensations: Hall and Motora, Amer. Journal of Psych., vol. I. stratton, Phil. Stud., vol. 12. Stern, Psychologie der Veränderungsauffassung, 1898.
 
 

11. As special cases among the apperceptive comparisons generally falling under weber's law, are the comparisons of magnitudes which are related to each other as relatively greatest sensation differences or, when dealing with feelings, as opposites. The phenomena which appear in such cases are usually grouped together under the class name contrasts. In the department where contrasts have been most thoroughly investigated, that is, in the case of light sensations, there is generally an utter lack of discrimination between two phenomena which are obviously entirely different in origin, though their results are to a certain extent related. We may distinguish these as light induction or physiological contrast (p. 79), and true contrast or psychological contrast. Physiological contrasts are closely connected with the phenomena of after-images, perhaps they are the same (p. 77 sq.). Psychological contrasts are essentially different; they are usually pushed into the background by the stronger physiological contrasts when the impressions are intense. Psychological contrasts are distinguished from physiological by two important characteristics. First, psychical contrasts do not reach their greatest intensity when the brightness and saturation are greatest, but when the sensations are at the medium stages, where the eye is most sensitive to changes in brightness and saturation. Second, under favorable conditions psychical contrasts can be removed by comparison with an independent object. Especially the latter characteristic shows these contrasts to be unqualifiedly the products of comparisons. Thus, for example, when a gray square is laid on a black ground and close by a similar gray square is laid on a white ground and all are covered with transparent paper, the two squares appear entirely different; the one on the black ground looks bright, nearly white, while the square on the white ground looks dark, nearly black. Now after-images and irradiations are very weak when the colors are thus seen through translucent media, so that it may be assumed that the phenomenon described is a psychical contrast. If, again, a strip of black cardboard which is also covered with the transparent paper, and is therefore exactly the same gray as the two squares, is held in such a position that it connects the two squares, the contrast will be entirely removed, or, at least, very much diminished. If in this experiment a colored ground is used instead of the achromatic ground, the gray squares will appear very clearly in the corresponding complementary color. But here, too, the contrast can be made to disappear through comparison with an independent gray object.

12. Similar contrasts appear also in other spheres of sensation when the conditions for their demonstration are favorable. They are also especially marked in the case of feelings and may arise under proper conditions in the case of spatial and temporal ideas. Sensations of pitch are relatively most free from contrast, for most persons have a well developed ability to recognize absolute pitch and this probably tends to overcome contrast. In the case of feelings the effect of contrast is intimately connected with the natural opposition between affective qualities. Thus, pleasurable feelings are intensified by unpleasant feelings immediately preceding, and the same holds for many feelings of relaxation following feelings of strain, as for example in the case of a feeling of fulfilment after expectation. The effect of contrast in the case of spatial and temporal ideas is most obvious when the same spatial or temporal interval is compared alternately with a longer and with a shorter interval. In such cases the interval appears different; in comparison with the shorter it appears greater, in comparison with the longer, smaller. Here, too, the contrast between spatial ideas can be removed by bringing an object between the contrasted figures in such a way that it is possible easily to relate them.

13. We may regard the phenomena which result from the apperception of an impression the real character of which differs from the character expected, as special modifications of psychical contrast. For example, if we are prepared to lift a heavy weight, and find in the actual lifting of the weight that it proves to be light, or if we lift a heavy weight when we expected a light one, the result is in the first case an underestimation, in the second an overestimation of the real weight. If a series of exactly equal weights of different sizes are made to vary in size so that they look like a set of weights varying regularly from a lighter to a heavier, they will appear to be different in weight when raised. The smallest will seem to be the heaviest and the largest to be the lightest. The familiar association that the greater volume is connected with the greater mass determines in this case the tendency of expectation. The false estimation of the weight then results from the contrast between the real and the expected sensation.

References. On Light Contrasts: H. Meyer, Poggendorff's Ann. d. Physik, vol. 44. Helmholtz, Physiol. Optik, Pt. 2, § 24. J. Koehler, Archiv f. Psychol., vol. II. Wundt, Grundz., 5th ed., vol. II, chap. 10, Sect. 4. On Space Contrasts: MÜLLER-LYER, Zeitschr. f. Psych., vol. 9. Wundt, Geometr.-optische Tauschungen, Abh. d. sächs. Ges. d. W., 1898. On Time Contrasts: Meumann, Phil. Stud., vol. 8. On Feeling Contrast: Wundt, Grundz., 5th ed., vol. II, Chap. 11, Sect. 3. On Illusions of Weights through Contrast: Müller and Schumann, Pflüger's Archiv f. Physiol., vol. 37. Seashore, Studies from the Yale Psych. Lab., 1895.
 
 

As a combining function apperceptive synthesis is based upon fusions and associations. It differs from fusions and associations in the fact that some of the ideational and affective elements which are brought forward by the association are voluntarily emphasized and others are pushed into the background. The motives for the choice between the elements can be explained only from the whole previous development of the individual consciousness. As a result of this voluntary activity the product of this synthesis is a complex in which all the components are derived from former sense perceptions and associations, but in which the combination of these components may differ more or less from the original forms.

The ideational elements of a compound thus resulting from apperceptive synthesis may be regarded as the substratum for the rest of its contents, and so we call such a compound in general an aggregate idea. When the combination of the elements is peculiar, that is, markedly different from the products of associations, the aggregate idea and each of its relatively independent ideational components is called an idea of imagination or image of imagination. Since the voluntary synthesis may vary more or less from the combinations presented in sense perception and association, it follows that practically no sharp line of demarcation can be drawn between images of imagination and those of memory. But we have a more essential mark of the apperceptive process in the positive characteristic which appears in the fact that it depends on a voluntary synthesis, than we have in the negative fact that the combination does not correspond in character to any particular sense perception. This positive characteristic is also the source of a most striking difference between images of imagination and those of memory. The difference in question consists in the fact that the sensation elements of an apperceptive compound are much more like those of an immediate sense perception in clearness and distinctness, and usually also in completeness and intensity. This is easily explained by the fact that the reciprocally inhibitory influences which the uncontrolled associations exercise on one another, and which prevent the formation of fixed memory images, are diminished or removed by the voluntary emphasizing of certain particular ideational compounds. It is possible to mistake images of imagination for real experiences. In the case of memory images this is possible only when they become images of imagination, that is, when the memories are no longer allowed to arise passively, but are to some extent produced by the will. Generally, there are such voluntary modifications of memories through a mixing of real with imagined elements. All our memories are therefore made up of "fancy and truth"¹⁾. Memory images thus change under the influence of our feelings and volition to images of imagination, and we generally deceive ourselves with their resemblance to real experiences.

In the case of the activity of "imagination" the motive is the reproduction of real complexes of experience or of experiences analogous to reality. This is the earlier form of apperceptive analysis and arises directly from association. It begins with a more or less comprehensive aggregate idea made up of a variety of ideational and affective elements and embracing the general content of a complex experience in which the single components are only indefinitely distinguished. The aggregate idea is then divided in a series of successive acts into a number of more definite, connected compounds, partly spatial, partly temporal in character. The primary voluntary synthesis is thus followed by analytic acts which may in turn give rise to the motives for a new synthesis and thus to a repetition of the whole process with a partially modified, or more limited aggregate idea.

The activity of imagination shows two stages of development. The first is more passive and arises directly from the ordinary memory function. It appears continually in the train of thought, especially in the form of an anticipation of the future, and plays an important part in psychical development as a preparation or antecedent of volitions. It may, however, in an analogous way, appear as a representation in thought of imaginary situations or of successions of external phenomena. The second, or active, form of imagination is under the influence of a fixed idea of some end, and therefore presupposes a high degree of voluntary control over the images of imagination, and a strong interference, partly inhibitory, partly selective, with the memory images that tend to push themselves into consciousness without voluntary action. Even the first synthesis of the aggregate idea is more systematic when produced by this active process. And an aggregate idea, when once formed in this way, is held more firmly and subjected to a more complete analysis than in passive imagination. Very often the components themselves are subordinate aggregate ideas to which the same process of analysis is again applied. In this way the principle of organic division according to the end in view governs all the products and processes of active imagination. The productions of art show this most clearly. Still, there are, in the ordinary play of imagination, the most various intermediate stages between passive imagination, or that which arises directly from memory, and active imagination, or that which is directed by fixed ends.

16. In contrast with this imagination or imaginative reproduction of real experiences, or of experiences which may be thought of as real, the function of the "understanding" is the perception of agreements and differences and other derived logical relations between contents of experience. Understanding also begins with aggregate ideas in which a number of experiences which are real or may be ideated as real, are voluntarily set in relation to one another and combined into a unitary whole. The analysis which takes place in this case, however, is turned by its fundamental motive in a different direction. Such analysis consists not merely in a clearer grasp of the single components of the aggregate idea, but it consists also in the establishment of the manifold relations which exist between the various components and which we may discover through comparison. In establishing such relations it is possible, as soon as analyses have been made several times, to introduce into any particular case the results gained through relating and comparing processes which were carried out on other occasions.

As a consequence of this stricter application of the elementary relating, and comparing functions, the activity of understanding follows definite rules even in its external form, especially when it is highly developed. The fact which showed itself in the case of imagination and even of memory, appears here in a developed form. The fact in question is that the apperceived relations between the various psychical contents are presented in imagination and memory, not merely simultaneously, but successively, so that we proceed from one relation to the next, and so on. In the case of understanding, this successive presentation of relations develops into the discursive division of the aggregate idea. This is expressed in the law of the duality of the logical forms of thought, according to which, analysis resulting from relating comparison divides the content of the aggregate idea into two parts, subject and predicate, and may then separate each of these parts again once or several times. These secondary divisions give rise to grammatical forms which stand in a logical relation analogous to that of subject and predicate, such as noun and attributive, verb and object, verb and adverb. In this way the process of apperceptive analysis results in a judgment which finds expression in the sentence.

For the psychological explanation of judgment it is of fundamental importance that judgment be regarded, not as a synthetic, but as an analytic function. The original aggregate ideas which are divided by judgment into their reciprocally related components, are exactly like ideas of imagination. The products of analysis which result from judgment are, on the other hand, not as in the case of imagination, images of more limited extent and greater clearness, but conceptual ideas, that is, ideas which stand, with regard to other partial ideas of the same whole, in some one of the relations which are discovered through the general relating and comparing functions. If we call the aggregate idea which is subjected to such a relating analysis a thought, then a judgment is a division of this thought into its components, and a concept is the product of such a division.

17. Concepts found in this way are arranged in certain general classes according to the character of the analyses which produced them. These classes are the concepts of objects, concepts of attributes, and concepts of states. Judgment as a division of the aggregate idea, sets an object in relation to its attributes or states, or it sets various objects in relation to one another. Since a single concept can never, strictly speaking, be thought of by itself, but is always connected in the whole idea with one or more other concepts, the conceptual ideas are strikingly different from the ideas of imagination because of the indefiniteness and variableness of the former. This indefiniteness is essentially increased by the fact that as a result of the like outcome of different kinds of judgment, concepts arise which may form components of many ideas which differ in their concrete characters. A concept of this kind can therefore be used in a great variety of different applications. Such general concepts constitute, on account of the wide application of relating analysis to different contents of judgment, the great majority of all concepts; and they have a greater or smaller number of corresponding single ideational contents. A single idea is selected from this group of contents as a representative of the concept. This gives the conceptual idea a greater definiteness. At the same time there is always connected with this idea the consciousness that it is merely a representative. This consciousness generally takes the form of a characteristic feeling, the conceptual feeling. This feeling may be traced to the fact that obscure ideas, which have the attributes which make them suitable to serve as representations of the concept, tend to force themselves into consciousness in the form of memory images. As evidence of this we have the fact that the feeling is very intense when any concrete image of the concept is chosen as its representative, as for example when a particular individual stands for the concept man, while it disappears almost entirely as soon as the representative idea differs entirely in content from the objects included under the concept. Word ideas fulfill this latter condition and that is what gives them their importance as universal aids to thought. Word ideas are furnished to the individual consciousness in a finished state, so that we must leave to social psychology the question of the psychological development of the processes of thought which are active in their formation (comp. § 21, A).

18. From all that has been said it appears that the activities of imagination and understanding are not specifically different, but interrelated; that they are inseparable in their rise and manifestations, and are based at bottom on the same fundamental functions of apperceptive synthesis and analysis. What was true of the concept "memory" (p. 277), holds also of the concepts "understanding" and "imagination"; they are names, not of unitary forces or faculties, but of complex phenomena made up of the usual elementary psychical processes; they are not made up of elementary processes of a specific, distinct kind. Just as memory is a general concept for certain associative processes, so imagination and understanding are general concepts for particular forms of apperceptive activity. They have a certain practical value as ready means for the classification of a variety of differences in the capacity of various persons for intellectual activity. Each class thus found may in turn contain an endless variety of gradations and shades. Thus, neglecting the general differences in grade, we have as the chief forms of individual imagination the perceptive and combining forms; as the chief forms of understanding, the inductive and deductive forms, the first being mainly concerned with the single logical relations and their combinations, the second more with general concepts and their analysis. A person's talent is his total capacity resulting from the special tendencies of both his imagination and understanding.

References. Wundt, Lectures, lecture 21; Logik, vol. I, chap. 1; Völkerpsychologie, vol. I, Pt. 2, chap. 7.