Thinking

THINKING, in psychology—the highest and most complex form of intellectual activity, consisting in the rational processing of data from experience, in the processes of establishing connections, revealing relationships and dependencies, and distinguished by its specific composition, structure, and method of functioning. In associative psychology, the processes of thinking were identified with the processes of associative combination of a series of object or verbal images and were considered as a special kind of associative flow of representations. The merit of the Würzburg school (O. Külpe, K. Bühler, N. Ach, Messer) lies in the fact that they subjected the processes of thinking to systematic experimental research with the aim of establishing their qualitative uniqueness compared to other psychological processes and their irreducibility to any associative combinations of visual images. These studies indeed showed the error of identifying thinking with associative processes and the independence of this form of intellectual activity. Initially, this uniqueness of thinking was revealed from the side of phenomenological analysis from the point of view of the direct experience of the processes and acts of thinking. Subjectively, the act of thinking is an experience sui generis, and not a complex composite formation that combines a series of image elements. Subsequently, some distinctive features of thinking were revealed not only from the side of experiencing these processes, but also from the side of their functioning. Thus, K. Bühler's experiments showed that thoughts are remembered differently than images, that they are connected with each other, causing one another to appear, replacing one another, without obeying the laws found for the associative flow of representations. The laws of flow, connection, and reproduction of thoughts were also subjected to experimental analysis from this basic point of view, and from this side, the irreducibility of thinking to simple associative activity was experimentally established. However, the significance of these research is almost exclusively exhausted by the purely negative conclusions that were drawn from them. The positive characterization of the processes of thinking, extremely palely represented in the works of the Würzburg school, reflects all the methodological errors of this direction. The main and most important of them is that in the analysis of the processes of thinking, these psychologists relied exclusively on self-observation. It can be said without exaggeration that here introspection was brought to its highest form, was used in its extreme possibilities. But in these same experiments, it revealed a relatively narrow circle of its possibilities and complete unsuitability to serve as the only and basic method of psychological research, in particular, of research on thinking. As one of the main conclusions of these studies, it was established that the processes of thinking, unlike the processes of representation, elude self-perception by the subject experiencing them, that the very act of thinking is not amenable to self-observation. Based on the inaccessibility of the process of thinking to precise self-observation and on the absence of visual images in these processes, psychologists of this direction tended to consider thinking as a purely spiritual act, completely unrelated to the processes of sensory experience. Külpe formulated the main conclusion to which these studies led in the following form: "We are again on the path to ideas." The attempt of the Würzburg school to break through from associationism, the attempt to prove the uniqueness of thinking processes and their irreducibility to association, actually turned out to be a step backward—to the ideas of Plato. Naturally, such an understanding of thinking was closely connected with the basic idealistic concept that lay at the basis of these studies. "We will not only say," summarizes Külpe the result of these studies, "I think, therefore I am, but also—the world exists as we establish and determine it." This concept represents a polar opposite to the dialectical-materialistic understanding of thinking, proceeding from the recognition that "consciousness does not determine life, but life determines consciousness" (Marx), that thinking is a reflection of reality, and finally that "thinking and consciousness are products of the human brain" (Engels). In the light of this idealistic understanding of the problem of thinking, the acts of thinking lost all connection with more elementary forms of figurative thinking and were considered not only as irreducible to processes of a more elementary order, but also as completely unrelated to them. Thinking was recognized as a pure primary act, just as primary as sensation. This supersensory character of the acts of thinking for the authors of the theory is connected with the non-visualizability of the act as the main distinctive feature of the processes of developed abstract thinking. Unlike the basic dogma of associative psychology, which considered all complex processes as combinations of representations, the new experiment could easily establish that states of intense thinking are extremely poor in image elements, can proceed without the participation of these latter, and that these visual elements play an insignificant role in the processes of thinking, do not form their core. And conversely, states rich in figurative experiences, like dreams and reveries, can be extremely poor in thought. But also in the solution of the problem of imageless thinking, the main methodological vices of all these research as a whole manifested themselves. Limiting themselves to the study of higher, most developed and moreover abstract forms of thinking, these psychologists metaphysically considered thinking not in the aspect of development and its connections with other forms of intellectual activity, but took the special distinctive features of these higher forms of thinking found by them as something primary, as a purely spiritual essence of this type of activity. Self-observation, used as the only method of research on the processes of thinking, inevitably leads to ignoring the comparative genetic research of the problem as a whole, and consequently to false conclusions. Indeed, in these experiments, many functional peculiarities of thinking were established, which retain their actual significance outside the basic concept with which they were obtained. Thus, the active, volitional character of higher forms of thinking, which allows us to speak not only of processes but also of acts of thinking, and to consider thinking as an activity, the close connection of this activity with the personality and with its self-consciousness, the specific direction of all processes of thinking toward the solution of certain tasks, and the functional role of these tasks—all this received its justification in more comprehensive and differently oriented research. However, these further research, confirming the purely negative conclusions of the Würzburg experiments and some functional and introspective peculiarities of the processes of thinking, as they were established in these experiments, at the same time led to a radical and complete negation of the main positive conclusions of the Würzburg school and of its basic concept as a whole. The research of thinking in the historical aspect—from the point of view of development—showed not only the uniqueness of thinking compared to other, more elementary processes and its irreducibility to associations, but also the close genetic connection, consisting in the fact that thinking develops and arises on the basis of these more elementary processes. In particular, the problem of figurative and imageless thinking received its resolution as the problem of different forms of thinking corresponding to two different genetic stages in the process of development. Figurative thinking, directly connected in turn with visual thinking and practical intelligence, which can be already observed in the behavior of animals, is genetically an earlier and more primitive form of thinking, which begins to give way to other forms with the development of verbal or word thinking. Recently, E. Jaensch experimentally showed the presence of these early forms of figurative thinking in ontogenesis and singled out in his experiments on eidetics among other forms of concrete, visual thinking such complex processes of combination and fusion of images that they allow comparison with the formation of concepts in abstract thinking and are therefore considered by Jaensch as processes of visual concept formation. However, figurative thinking does not disappear immediately with the appearance of the verbal form of thinking. It continues to play still a very significant role in the so-called primitive, or pre-logical thinking, which already uses the word as a means of thinking and, due to constant confrontation with life practice, contains a series of germs of real logical thinking, but which is still deeply different from developed logical thinking in concepts from the functional, structural, and genetic side. The research of the thinking of primitive man led psychologists to establish a special type of primitive thinking, which, due to its genetic connection with logical thinking, is usually called, following Lévy-Bruhl, pre-logical. Similar forms of pre-logical thinking were revealed by researchers also in the processes of the development of children's thinking. If one attempts in a general schematic form to outline the main stages through which verbal thinking passes in its development, one can establish three main, genetically interconnected forms of verbal thinking.

The first form can be called syncretic thinking, keeping in mind that undifferentiated, holistic, and diffuse character which distinguishes the processes of thinking at this stage of development. At this stage, the prevailing type of connection in thinking is the connection of impressions. That which was united in perception simultaneously or successively, that which merged in a single experience or was otherwise connected in the area of immediate impressions, forms a single syncretic whole, a single undifferentiated image that lies at the basis of this most primitive type of thinking. The connection of impressions is taken as the connection of things, the predominance of subjective connections and the lack of objective connections characterize this stage in the development of thinking as its most essential distinctive features. With reference to comparison with logical thinking, P. P. Blonsky calls syncretic thinking 'the incoherent coherence of thought.' Many authors also call this type of thinking complex thinking (Preuss, Storch), since 'sharply delimited and abstract concepts are here replaced by complexes of images that imperceptibly merge into one another and blend into conglomerates' (Kretschmer). H. Werner (N. Werner) speaks of psychological amalgams as the basic units which this type of thinking operates with. A distinctive feature of this thinking is that it lacks characteristic features: objectivity, isolation, completeness, and differentiation—in other words—formulation. These images and their fusion are emotionally similar. That is why they characterize mainly affective thinking, which has not yet separated from emotional reactions (Kruger, H. Volkelt, Storch). However, it would be more correct to retain the name of complex thinking for the second type, for the second stage in the development of thinking, which is usually already associated with highly developed speech. The basis of complex thinking is the unification, generalization, and connection of individual objects according to some specific, figurative, factual coincidence in individual features or according to proximity based on concrete experience. Such complexes in primitive thinking take the place of our concepts. They represent concrete groups of objects and are characterized by the absence of uniformity and hierarchy in the connections that unite different elements into a single complex. For this type of complex thinking, which arises on the basis of a special use of the word as a 'family name' designating a specific collection of objects complexly united with one another, is characteristic that particular feature of primitive thinking which Lévy-Bruhl calls the law of participation. By this name he means a special relation established by primitive thinking between phenomena or objects that have no understandable connection from a logical point of view, spatial, temporal, or causal, and are considered by the primitive mind as partially identical with each other or as having a close mutual influence on one another. A deeper analysis has shown that the actual basis of such participation, established in primitive thinking, is not identification, as Lévy-Bruhl believes, but the partial approximation of different objects belonging to one complex, a kind of family relationship established between objects. Such connections, established by complex thinking, arise because this form of thinking presents reality in a different system of connections than developed logical thinking in concepts. In any case, there is no doubt the concrete, figurative character of primitive thinking. This figurative type of complex connections continues to play a decisive role also in the verbal thinking of primitive man. The place of concepts in this thinking is taken by concrete groups of images. The thinking of primitive people, in the expression of Thurnwald (Turnwald), uses documentary, undifferentiated impressions of phenomena. They think in entirely concrete images in the form in which reality presents them (Thurnwald). The third and highest stage in the development of verbal thinking is thinking in concepts. Without going into the consideration of the problem of the concept as a whole here, it is necessary to note only that psychological experiments on the formation of concepts lead to the negation of the traditional understanding of the psychological nature of the concept, transferred into psychology from formal logic. In formal logic and following it in traditional psychology, the concept was considered as the product of progressive abstraction, as a result of which thinking ascends from the particular to the general. The law of inverse proportionality of the volume and content of the concept was for a long time taken as the basic law of thinking. In reality, experiments have shown that even in the area of the visual formation of concepts or rather of general representations not connected with verbal thinking, such relations do not actually take place. In the already mentioned experiments of Jensch on the formation of visual concepts in eidetics, it was established that this process never proceeds by the abstraction of a series of common features in a group of similar objects, that the concept never resembles Galton's collective photograph. Jensch outlines two basic forms of the formation of visual concepts: 1) composition, in which individual features are selected from a series of concrete objects, which are then united into a new 'meaningful' whole constructed from these elements, and 2) fluxion, i.e., the dynamic unification of individual elements into a single series, the individual members of which, changing, flow one into another. In the area of true concepts, we certainly have no confirmation whatsoever of that path of concept formation which is outlined by formal logic. The concept, as experiments show, is not in general an image preceding the processes of thinking. It is not a premise but a product of thinking and reflects the object in all its multiplicity, in all its connections and relations, synthesized into a holistic unity. The concept—unlike representation and contemplation—is not immediate knowledge of the object, but mediated knowledge, arising as the result of the rational processing of representations of the object. Therefore, concepts, as noted by V. I. Lenin, reflect reality more deeply, fully, and correctly than representations. 'Hegel is entirely right in substance against Kant. Thinking, ascending from the concrete to the abstract, does not depart, if it is correct, from truth, but approaches it. The abstraction of matter, law, nature, the abstraction of value, etc., in a word, all scientific (correct, serious, not nonsensical) abstractions reflect nature more deeply, more correctly, more fully. From living contemplation to abstract thinking and from it to practice—such is the dialectical path of the cognition of truth, the cognition of objective reality' (V. Lenin). To convince oneself of this, it is sufficient to compare some definite concept with the corresponding concrete group representation, or complex, in primitive thinking. Let us compare, for example, the concept of number with those 'numerical formations' (Numeralgebilde) which, according to the research of M. Wertheimer, take the place of our numerical concepts in primitive thinking. Such a numerical image, connected with the direct perception of quantities, reflects the quantitative feature of a given collection of objects as one of many qualitative features characterizing this group. In terms of the concreteness of experience and figurativeness, before us is a much more direct, 'vital' and close-to-reality way of thinking. As is known, it gives the person using it a whole series of valuable advantages in terms of direct orientation in quantities. The primitive man is much better than the cultured man at visually comparing, determining, and identifying collections of objects in quantitative terms. But if the essence of the object is revealed most fully not in the immediately given experience, but in its connections, dependencies, and relations with the rest of reality, then the concept of number and the counting based on it possess inestimable advantages compared with primitive numerical images and represent the highest stage in the cognition of reality. The concept of some definite number (in contrast to its numerical image), by entering into the numerical system, at once reflects before us a whole series of such its peculiarities and properties in which its essence is revealed, which can never be revealed with the help of numerical images, with the help of complex type thinking. From the numerical image corresponding, for example, to the concept 9, we would never learn that this number is the square of 3, that it is not divisible by 2, finally we could never from this image derive its place in the system of the other numerical images and all its relations to each other member of this system. 'The formation of abstract concepts and operations with them already include in themselves representation, conviction, consciousness of the regularity of the objective connection of the world... Already the simplest generalization, the first and simplest formation of concepts, judgments, conclusions, etc., means the cognition by man of ever deeper and more objective connections of the world.' Thinking thus becomes the basis for the cognition of objective reality and the basis of human practice transforming this reality.

In connection with the problem of verbal thinking, there also stands one of the most complex questions regarding the relationship between thinking and speech. There exists a view that identifies thinking and speech and considers thinking as silent, internal speech or as 'speech minus sound.' Behaviorism in America and reflexology in USSR proceeded from such an understanding of thinking. However, more profound research shows that from a functional, structural, and genetic point of view, the identification of thinking and speech proves to be false. This research showed that thinking and speech have different genetic roots in ontogenesis and phylogenesis, that the development of these roots of thinking and speech proceeds along different lines and to a certain defined point independently of each other, that in phylo- and ontogenesis of thinking and speech we can with certainty establish a pre-speech phase in the development of intellect (the practical intellect of animals) and a pre-intellectual phase in the development of speech. The relationship between thinking and speech is not a constant value throughout the entire course of ontogenetic and phylogenetic development. Only in the process of development of thinking and speech does a complex connection arise between them, leading to the emergence of a new, qualitatively unique form of thinking. This research with sufficient clarity showed that verbal thinking is not a natural, innate form of behavior, but a historical form and therefore differs fundamentally by a whole series of specific properties and laws, which cannot be found in natural forms of thinking. For this highest form of verbal thinking, the formation of concepts is characteristic. The formation of concepts represents the most complex and highest, truly dialectical in its nature process of thinking. 'The approach of the mind (of man) to a single thing, the taking of a cast (concept) from it is not a simple, direct, mirror-dead act, but a complex, divided, zigzag-like act, including the possibility of the flight of fantasy from life; moreover: the possibility of the transformation (and moreover an imperceptible, not consciously realized by man transformation) of an abstract concept, idea into fantasy (in the final analysis = god). For even in the simplest generalization, in the most elementary general idea ('table' in general) there is a certain piece of fantasy' (V. Lenin). Empirical research also establishes the dialectical interdependence in the development of thinking in concepts and fantasy—both in ontogenesis and in phylogenesis. So-called autistic thinking, fantasizing, is not primary in the history of the development of thinking. It develops secondarily, encountering powerful support in the formation of concepts (Bleuler). Only thinking in concepts is logical thinking in the proper sense of the word. This type of thinking is usually called reflective thinking, since this thinking is turned on itself and requires reflection. Reflective thinking is thinking that is aware of its foundations, directed toward the investigation of those concepts with which it operates and connected with self-consciousness of the personality, which is aware and subordinates to its will the entire course of the process of thinking as a whole. But even this highest type of reflective logical thinking turns out to be closely connected with practical thinking. This connection of thinking with practice covers relations of a twofold order. On the one hand, practical,直观-行动 thinking is in the history of thinking a necessary prerequisite for the development of higher forms of thinking, in particular—verbal and abstract thinking. Thinking takes its origin from practice. On the other hand, from the moment of formation of logical verbal thinking, the entire series of practical functions is restructured on a higher basis and rises to a higher stage of development in connection with verbal thinking. As already stated, the practical intellect of animals, as shown by the research of W. Kohler, is the biological foundation of the entire history of the development of thinking. In man, as research shows, thanks to the combination of his practical activity with speech, there arises a reflection in speech of the basic forms of practically-effective intellect, the basic operations of practical thinking, there arises a verbal formula of practical thinking, which in turn then begins to direct and modify its practical operations.—'When Hegel tries, sometimes even strives and strains to bring the purposeful activity of man under the categories of logic, saying that this activity is a 'conclusion,' that the subject (man) plays the role of such-and-such a 'term' in the logical figure of the 'conclusion' and so on, then this is not only a game. There is here a very profound content, purely materialistic. One must turn it around: the practical activity of man had to bring the consciousness of man billions of times to the repetition of different logical figures, so that these figures could obtain the value of axioms... The practice of man, repeated billions of times, becomes fixed in the consciousness of man by the figures of logic. These figures have the durability of prejudice, an axiomatic character, precisely (and only) by virtue of the billion-fold repetition' (V. Lenin). Modern clinical and experimental research has shown that also in the processes of disintegration, breakdown, involution and pathological changes, the relationship between thinking and speech is not constant for all cases of disturbance, retardation, regression, but takes each time a specific form, characteristic precisely for this type of pathological process, for this particular disturbance and retardation. This research leads basically to that general conclusion that also in the area of research on the problem of thinking and speech, development is the key to understanding pathology, and pathology gives the key to understanding the processes of development. It is necessary to dwell only on two large forms of pathological changes of thinking and speech, observed in aphasia and schizophrenia, since they have primary importance for the general understanding of the problem of thinking and reveal some basic laws characterizing the interrelationship of thinking and speech. The research of Gelb and Goldstein showed that the main disturbance of thinking in amnestic aphasia consists in that the patient loses, in the expression of the authors, the categorical attitude toward reality, i.e., that attitude which is created by thinking in concepts. He descends in his thinking to genetically earlier, more concrete, more vital and closer to reality forms of thinking, displays a purely concrete attitude toward objects of reality, largely analogous to the thinking and speech of primitive man. The return to more primitive and genetically earlier stages in the development of thinking due to the breakdown of the function of concept formation and the resulting loss of the 'categorical attitude' toward objects of reality constitute, in the opinion of these authors, the main content of the aphasic disturbance of thinking and speech. Words cease to be for the patient signs of concepts. The categorical attitude and command of speech in its significative meaning, say these authors, is an expression of one and the same basic form of behavior. In physiological terms we must imagine that to this basic form of behavior there corresponds a certain basic brain function. Together with the activation of this basic function there arises categorical behavior and simultaneously the word in its significative meaning. With the lesion of this basic function both are disturbed. This last proposition appears to be completely in accordance with the basic conclusion which was made above regarding thinking in concepts. We saw that verbal thinking as a unique form of behavior and thinking in concepts in particular are a product of the historical development of thinking. They represent a historical, not a natural form of thinking. The same is testified to by the fact of the emergence of logical thinking from practical activity. Therefore it would be difficult to expect that thinking in concepts corresponds to one of the definite basic physiological functions of the brain, with the disturbance of which this form of thinking also disappears. It would be difficult to expect that primitive man, not commanding thinking in concepts, i.e., categorical behavior, and showing a far-reaching analogy with the aphasic patient, as the authors themselves indicate, was deprived of some basic physiological function of the brain, as it would be difficult to expect that in the process of historical development of man there arose by the way which was briefly described above—from human practice—a new and moreover basic physiological function of the brain. The logical forms of thinking, which are a reflection of the basic operations of human practice, practical inferences, are a product of historical and therefore social development of behavior by the combination of elementary functions into higher syntheses. 'Only people who develop their material production and their material relations also change in this activity their thinking and the products of their thinking' (Marx). The detachment of thinking from labor practice, which is its foundation, from the real historical soil on which it arises and develops, inevitably leads to the biologization of thinking, to the consideration of its historically arisen forms as immanently inherent to the brain physiological functions. Of course, concepts, by Lenin's definition, are 'the highest product of the brain, the highest product of matter'—but a product that arose historically and is conditioned by the entire course of the historical development of man. In the light of the modern doctrine of thinking in concepts, it seems to us that there arises and no need for the assumption of the kind which is made by the authors.

In order to explain from the physiological side the emergence of this new historical form of Thinking, it is sufficient to assume that in the structure of the brain and in the system of its functions there is the possibility of the emergence of new combinations, new syntheses, new functional associations, there are conditions, foundations and prerequisites for their development, and not at all given in a ready-made form the physiological correlates of higher psychological functions, which are the product of historical development. In this sense, the definition of the essence of that disorder which we observe in aphasia, as proposed by Head, is probably closer. Head sees in it a violation of the function of 'symbolic formulation and expression.' By this, Head means 'such a way of behavior in which some symbol, verbal or other, is interposed between the beginning of an act and its final execution. This covers many ways of behavior which are not usually considered as forms of verbal behavior and which therefore require empirical research and establishment.' Head establishes a far-reaching connection between the basic disorder in Thinking and similar disorders in other higher psychological functions, insofar as they require the participation of symbolic Thinking. This affinity of the most diverse, from the point of view of physiological correlates, ways of behavior, which suffer in aphasia, also speaks against the assumption (made by Gelb and Goldstein) mentioned above. This question is closely connected with the basic question regarding the localization of that higher nervous synthetic activity which underlies Thinking. Research shows that these higher intellectual functions are connected with the undamaged state of the cerebral cortex, but without a continuous, sharply delimited localization. All brain processes which lead to extensive damage to the cerebral cortex lead to a disorder of Thinking (Kretschmer). To speak of the presence of a certain 'territory' (in the cerebral cortex) as the substrate of Thinking is correct only insofar as we are dealing with brain areas predominantly related to Thinking. When these are affected, disorders of Thinking occur with the greatest necessity and are most sharply expressed (frontal lobe, so-called speech area). The carrier of Thinking is the cortex as a whole, and not one or another of its parts, and the basis of verbal Thinking is a complex cooperation, a complex constellation of a series of more elementary functions connected with various parts of the cerebral cortex. The data of the latest research, both experimental and clinical, accordingly lead us to assume that the problem of the localization of Thinking will receive its solution in the aspect of studying the integrative function of the brain as a holistic dynamic system, the work of which is characterized by the presence of mobile functional structures, which include in their sphere and unite in an organized whole, in a single synthesis, the processes in various parts of the brain. In particular, bearing in mind that the process of Thinking is closely connected with the affective sphere, the violation of which can lead to severe disorders of Thinking ('autistic thinking' by Bleuler), we must assume that subcortical formations also play an important role in the overall apparatus of thinking. Proof in favor of the above assumption regarding the character and physiological nature of Thinking we find in the fact that in the most diverse diseases this function suffers in the first place. Thus, Storch's research showed that in schizophrenia there is also a breakdown of the function of concept formation and a return to an archaic-primitive complex type of Thinking. At the basis of all such disorders of Thinking, encountered in the most diverse diseases, there lies such a genetic return to already passed and left behind stages, which again allows for a broad analogy (but by no means an identification) with the Thinking of primitive man. But the most important in this research is the indication that together with the breakdown of the function of concept formation, the consciousness of reality and self-consciousness of the patient are altered. Objective consciousness loses its form and constancy, it descends to an earlier, from the point of view of psychological development, stage of complex qualities. The same thing happens with self-consciousness. There is a blurring of the boundaries between the 'I' and the surrounding world, a breakdown of the unity of the personality into separate components. Just as in the first case undifferentiated visual complex qualities replace the world of formed things, so in this case the place of a completed consciousness of 'I' is taken by the complex coexistence of partial components (Storch). The history of the development of the function of concept formation in the transitional age also shows that the consciousness of reality and self-consciousness of the personality, as they are characteristic of the adult cultured person, arise on the basis of concept formation. All higher psychological functions (so-called logical memory, voluntary attention, volitional functions), the disturbance of which we observe simultaneously with the loss of 'categorical thinking' in aphasia, are restructured in this age on a higher basis, which is also concept formation. Thus, the research of development, as well as the study of the breakdown of higher psychological functions and of the entire Personality and worldview as a whole, accordingly lead to the conclusion that Thinking is one of the most important functions in the general system of development and formation of the personality. Therefore, it is a great mistake to consider Thinking in its highest forms as the direct result of the activation of the 'basic brain function,' as a psycho-physiological function laid down from the very beginning in the organization of the brain in a ready-made form (Goldstein). Essentially the same error, consisting in ignoring the historical development of Thinking, lies at the basis of another widely spread delusion in the theory of Thinking, which assumes that the breakdown of Thinking means a return to already passed stages of phylogenetic development of Thinking, to its archaic-primitive forms, as if laid down in a ready-made form and fixed once and for all in the brain or in the psychological apparatus of man (Storch). The same error - anti-historicism - in the theory of Thinking leads to the postulation of some original 'higher force' which sets in motion the processes of Thinking and is sometimes understood as a purely spiritual force, as the ability to 'symbolic formulation and expression' (Head), as the 'higher intentional sphere' (Vegez, Kronfeld), from which higher forms of Thinking are derived. Overcoming these delusions is possible only by the path of historical research into Thinking. - On the problem of Thinking in the philosophical and historical aspect - see Psychology, Speech, Consciousness. - On the types of disorders of Thinking in individual forms of mental diseases - see (Manic-depressive psychosis, Paranoia, Epilepsy, etc.).