PSYCHOLOGY. — From the Greek ψυχή, λόγος, it is the “doctrine or science of the soul,” of its nature and its operations. The term psychology comes from C. Wolff (v.), who first distinguished a “rational psychology” and an “empirical psychology”: the former proceeds from the principles of metaphysics (v.) and thus constitutes a kind of “special metaphysics,” while the latter is based solely on the observation of facts of experience (v.). It is precisely in this dualism that the main difficulty lies in determining the nature and tasks of psychology.
I. THE PROBLEM OF PSYCHOLOGY AS A SCIENCE
The difficulty in determining the nature of psychology arises from the very position that man occupies in the world. Indeed, if from the analytical and systematic point of view psychology constitutes a particular sphere of philosophical reflection, it is clear that from the synthetic point of view psychology is at once the beginning, the means, and the end of the orientation of human consciousness itself, inasmuch as in man everything starts, unfolds, and culminates in the soul. Therefore, if the soul (v.) is the “principle of life in living beings,” it is so first of all in man, indeed in the individual subject, inasmuch as each person can experience life for himself and can understand it in others only on the basis of his own experience, first in other men and then in animals down to the lowest degree of plant life. The understanding of life, as elaborated by psychology, thus results from the complex articulation of experiences and reflections that begin with one’s own life and the relationships that each person has with the human world and beyond.1. There is first the relationship with nature (v.) in which man moves and which moves around him; it is therefore a question of determining whether every movement, in the animal, plant, and physical world, has the soul as its principle and cause and how it can derive from it (cosmological problem: Greek philosophy). 2. There is then the relationship of the soul with the body in which it dwells and which it moves to perform the operations of life. This is the most difficult problem of psychology, to which the ultimate answer concerning man’s destiny is directed: whether soul and body are two complete or incomplete natures, whether the soul influences the body and the body the soul, whether the soul begins and ends its existence with the body or comes from elsewhere and goes elsewhere at death (metaphysical problem: Christian philosophy). 3. There is further, and consequently, the problem of the relationship of the individual with other men, both with present individuals and with those of different civilizations and cultures, of various races and ethnic differences that constitute the historical development of humanity (historical-anthropological problem). 4. Finally, there is the problem of the origin and end of life and thus of man’s relationship with divinity (existential problem). In the historical development of psychology, these problems are variously present and intertwined, tending to predominate over one another, yet not so as to absorb completely the others but rather to subordinate them to the one considered principal, which then qualifies the others as secondary. It is therefore not surprising that psychology presents itself at once as the science and knowledge closest to man and as destined to remain ever incomplete, contested, and resumed: in this way psychology, more than following the condition of other sciences that in the history of human thought appear in continual transformation, is itself the reason and stimulus for this very transformation. It should therefore not be surprising that the problem of determining the nature of psychology remains still open.
The enigma proper to psychology is constituted in its paradoxical condition by the following elements: a) the primordial and underivable phenomenological certainty that the soul has of its existence in its acting, inasmuch as no act can be given, whether in the cognitive or practical and objective sphere, without the concomitant consciousness on the part of the individual subject (the ego [v.], the individual soul) that he knows and acts. b) The unbridgeable metaphysical distance between the activities of the soul and its essence: first, the operations are “many,” and the soul must be “one” to guarantee the unity of being; then, the operations are “different,” and at times even contrasting, while the soul must be inwardly gathered, “simple,” and indivisible. c) The metaphysical opposition of soul and body inasmuch as the soul is the first invisible moving principle (and in man of a spiritual nature), while the body is a visible reality moved by the impulses of the soul and of a material nature: it is not understood how two elements that stand at the opposite extremes of being can converge in a unity of nature. d) The functional opposition of consciousness, subconsciousness, and unconsciousness, inasmuch as while the presence of the soul to itself and of objects to the soul is precisely given in the act of consciousness (v.), such an act is bound by limits of time and space, however variable from subject to subject, yet always inevitable: hence the problem of the relationship between soul and consciousness, and between consciousness, subconsciousness, and unconsciousness.
The characteristic situation of psychology consists in being at once the primary consideration that bears on the essential principle of knowing immediately present to itself (consciousness) so as to precede every other form of reflective knowledge, and in being a secondary consideration inasmuch as, in order to pass to the determination of its own nature, this principle must reflect on its practical relationship to known things and have recourse to the reflective principles of metaphysics. The historical development and stages of psychology depend on the predominance and varying emergence, in different epochs and cultures, of the one or the other of the indicated moments.
There has been written. — In early Greek philosophy the soul is considered predominantly as the “principle of movement of the phenomena of the cosmos”; hence there is no concern to found and develop a psychology, since the consideration of the soul coincides with that of being and of nature (v.). A particular interest in the soul emerged in Heraclitus: he affirms its profound mystery (fig. 45): “The limits of the soul you would not discover, even if you traveled every path; so deep is its logos.” Heraclitus, Fragments, text and Italian trans. by R. Walzer, Florence 1936, p. 82) and the personal individuality that accompanies it, in the different destiny that the just and the unjust have after death: even though this does not accord with the rest of his cosmological conception. While the Ionian philosophers did not properly sense the problem of the soul and Parmenides limits himself to considering the problem of knowledge, Heraclitus perceived the problem of the self (fig. 101): “I searched myself,” op. cit., p. 135), so that it has been rightly said that “in Heraclitus one finds for the first time a psychology worthy of the name” (K. Reinhardt, Parmenides und die Gesch. der griech. Philosophie, Bonn 1916, p. 201). Nevertheless, psychology as a metaphysical construction had its development along the ontological line with Anaxagoras (v.); the nous as the principle of cosmic order, Plato (the nous as the principle of eternal motion) and Aristotle (the nous as that which it is to be nous, principle of eternal motion and at the same time as the principle of all the operations of the living being). Aristotle’s De anima in three books is the first systematic treatise on psychology that has come down to us from antiquity; it constitutes the summit of Aristotelian speculation and, after so many vicissitudes in the life of thought, remains still the principal source of the consciousness of Western man: of these books Hegel wrote that “they are still, for the treatments they contain concerning particular aspects and states of the soul, the best work and the only one of speculative interest on this subject” (Enzyklop. d. phil. Wissenschaft, Philosophie des Geistes, § 378, ed. J. Hoffmeister, Leipzig 1949, p. 327). The same Hoffmeister has found a translation made by Hegel of passages from the De anima with commentary: cf. Vorlesungen über die Gesch. der Philos., XV, part 1, Leipzig 1944, p. xiv).
The originality of Aristotelian psychology lies in the synthesis of the conception of the soul as immanent form (“act of the body”: De anima, II, 1, 412 a 21) and as transcendent form (the active spiritual nous: ibid., III, 5, 430 a 11 ff.). Epicurean and Stoic psychology is a return to materialism (v.) in polemic against the mixture of spiritualism (v.) and materialism of which Aristotelian psychology is accused. Neoplatonic psychology returns to the primacy of the cosmic function of the soul, but at the same time, with the theory of ontological emanation, it posits the principle that will be developed in medieval psychology concerning the derivation of souls and inferior potencies from superior ones. Patristic psychology unfolds the concept of man in the new climate of faith and grace and draws from revelation (v.) the notions of the individual (v.), of the spirituality and immateriality (v.) of the personal soul which is created directly by God; though with the oscillations of the Fathers on some points (St. Augustine for the direct creation by God, Tertullian for absolute spirituality: cf. his proof of the materiality of the soul in De anima, ch. 7, ed. J. H. Waszink, Amsterdam 1947, pp. 9 and 148 ff.: extensive commentary with indication of sources). The most complete treatise, of eclectic inspiration, which fuses classical psychology with Christian doctrine, is the De natura hominis of Nemesius, bishop of Emesa (cf. B. Domanski, Die Psychologie des Nemesius, Münster in V. 1900, p. vii ff.).
The history of psychology in the Hellenistic period, throughout the Middle Ages, down to the Renaissance, revolves around Aristotle’s De anima. The commentaries can take three forms: 1) continuous literal analysis (e.g., the great commentaries of Alexander of Aphrodisias, Simplicius, John Philoponus); 2) paraphrase (Themistius); 3) questions (the same Alexander in ‘Απορίαι καὶ λύσεις). The Arabs, as in other fields of culture, follow Greek models in psychology too; for philosophy, at first the Platonic and Neoplatonic current prevails, which continues even in commentaries on Aristotle. Avicenna (v.) follows the paraphrastic method, while Averroes (v.) adheres to and develops, with continual reference to the Greek tradition, the literal method. Among the medievals, while St. Albert the Great follows the line of Avicenna, his disciple St. Thomas deepens the method of Averroes. In medieval psychology two tendencies are contrasted: the Augustinian school, tinged with Avicebronism, on the one hand with St. Bonaventure, who defends the so-called Christian Platonism, and the Aristotelian Thomist school on the other, which adheres to the principles of the philosopher. The principal points of divergence concerned: 1) The metaphysical structure of the soul, which the Augustinian school held to be composed (and so also the angels) of matter and form, while St. Thomas defends its absolute essential simplicity (cf. De spiritualibus creaturis, a. 1). 2) The relation of the soul to its faculties: real identity for some, real distinction according to St. Thomas (Summ. Theol., 1a, q. 77, a. 1). 3) The mode of knowledge: the Augustinian school, following the doctrine of St. Augustine, accepts the distinction of ratio inferior and ratio superior, in that the former is intent upon eternal reasons, while the latter is intent upon inferior things by directing them to higher things (St. Augustine, De Trinitate, XII, ch. 3, nn. 3-4: PL 42, 88). St. Thomas, on the other hand, according to the Aristotelian doctrine, attributes these functions to the agent and possible intellect inasmuch as it has the capacity to “abstract” from experience the cognition of the essence of things. In the face of Averroism, which, with the pretension of integrally summarizing Aristotle, defended the existence of a single eternal and impersonal intellect for the whole human species, Thomism proved itself more active and effective.
Humanism and the Renaissance, while extolling the primacy of man in the cosmos, exhaust themselves in certain particular points (immortality of the soul, free will, providence) and offer no constructive psychology worthy of note (cf. E. Cassirer-Kristeller-Randall, The Renaissance philosophy of man, Chicago 1945, p. 5).
Modern philosophy has overturned the situation of psychology. Preceded by the scepticism of the nominalist school, modern thought, especially from Descartes onwards, has identified “truth” with “certainty.” Certainty, in turn, has been reduced to the presence of “consciousness” to itself (the so-called *cogito* or “principle of interiority”). Leibniz’s “closed world” (*v.*) aims to be a revival of Aristotelian *entelechy* (*v.*) unified with the new principle of consciousness. English empiricism, culminating in Hume’s phenomenism (*v.*), reduces psychology to the analysis of the elements (impressions and ideas) of consciousness. Finally, with Kant (the *Das Ich denke überhaupt* or “transcendent consciousness”) and especially with the idealist systems that derive from him, “consciousness” (*Bewusstsein*) becomes “universal self-consciousness” (*das allgemeine Selbstbewusstsein*), and psychology is absorbed into metaphysics (*v.*).
Hegel (*v.*) sought to distinguish between phenomenology and logic, but in the continuous travail of his thought the distinction never became clear (cf. *Wissenschaft der Logik*, ed. Lasson, Leipzig 1932; I, Vorrede, p. 7: phenomenology precedes the system, whereas in the *Enzykl.* [cf. § 413] it forms part of it); the Hegelians regard psychology as a section of the “doctrine of spirit,” that is, as the consideration of “subjective spirit” (cf. C. L. Michelet, *Anthropologie oder Psychologie des subjektiven Geistes*, Berlin 1840, p. 5, *v.* 3). The fundamental error of modern psychology has been to split (already with Descartes) human nature into “thought” and “extension,” thus positing the obligatory alternative of materialism and idealism: thus, after the predominance of the idealist principle in the first half of the 19th century, the second half saw the predominance of positivist and materialist psychology (“psychology without a soul,” *Psychologie ohne Seele*, in the words of F. A. Lange: *Gesch. des Materialismus*, I. II, sect. 3; 3rd ed., Iserlohn 1877, p. 381).
Nevertheless, modern philosophy may be credited with having stimulated the search for individual interiority and the understanding of the concept for grasping that sense of man’s temporal existence which classical philosophy, under the dominion of “nemesis,” had swallowed, while medieval philosophy had devoted itself chiefly to metaphysical disputes. The principal error of modern psychology has been to transform the functional, or operative, subjectivity of consciousness into phenomenological subjectivity, reducing the world to appearance and finally making ontological subjectivity the constitution of being (hence the accusation of “psychologism” (*v.*) levelled at modern thought by Gioberti). In this way consciousness itself has been annihilated by asphyxiation for having isolated and reified its intentional function (cf. the analysis of the “dogma von der Selbstbefangenheit des Bewusstseins” by Ph. Lersch, *Seele und Welt. Zur Frage nach der Eigenart des Seelischen*, Leipzig 1941, especially pp. 25 ff.).
In contemporary culture psychology has branched into two main directions: experimental psychology and what is properly called “philosophical anthropology.” Experimental psychology undertakes the analysis, description, and investigation of the laws of the various classes of psychic facts in order to arrive at a conception of human behaviour from a strictly scientific, i.e., objective, standpoint. Its historical beginning may be placed with Fechner’s discovery of the “psychophysical law” (*v.*) which aims to define the relation between the intensity of a stimulus and the increase of sensation; but its true methodological beginning is to be seen in the founding of the first laboratory for experimental research by W. Wundt in Leipzig in 1870, which, through his writings and those of his pupils, explored almost all the problems of the new science, dwelling especially on the representative and emotive synthetic functions. Among the founders of modern psychology must be mentioned the physicists and physiologists E. H. Weber, H. Helmholtz, J. Müller, E. Hering, J. V. Kries, who contributed to the analysis of sensations. The higher functions of memory, understanding, and volition were successfully explored by the school of Külpe (*v.*), who, nourished by profound philosophical studies, first applied the method of introspection (*v.*) scientifically, vindicating, against positivist and neo-Kantian psychology, the absolute originality of higher life. To this trend belong the most convinced advocates of spiritualism in psychology, such as F. De Sarlo, A. Gemelli, A. Michelet, S. De Sanctis; in America, Titchener with his numerous pupils. Among the most recent trends in psychology up to the Second World War must be mentioned the “Gestalt psychology” founded by M. Wertheimer and developed by numerous and brilliant collaborators such as K. Koffka, W. Köhler, K. Lewin; a related trend is the “Ganzheitspsychologie” (holistic psychology) of F. Krueger, Wundt’s successor at Leipzig. A trend that quickly gained ascendancy in American psychology is the “behaviourist” psychology (*behaviorism*) which excludes every psychic factor, initiated by J. Watson and now represented by Tolman. Also to be reckoned as psychology, though tainted with philosophical preconceptions, is psychoanalysis (*v.*), founded by S. Freud, which concerns itself with the analysis of the subconscious in order to obtain a unitary “causal” explanation of psychic life. In the Catholic field, the Catholic Universities of Louvain, Milan, and Washington have for nearly half a century carried on fruitful and appreciated work in defence of a spiritualist psychology.
An original way of orienting the problems of psychology as a “science of the spirit” (*Geisteswissenschaft*) is philosophical anthropology, a strictly theoretical discipline. Its beginning may be placed with W. Dilthey’s distinction between “descriptive” and “explanatory” psychology (*deskriptive und erklärende Psychologie*); its brilliant investigator was M. Scheler (cf. *Vom Ewigen im Menschen*, 2nd ed., Leipzig 1923, and *Die Stellung des Menschen im Kosmos*, 4th ed., Neuburg 1949). The peculiar object of philosophical anthropology is not merely the knowledge of the objective properties of man as a “natural being” (*als Naturwesen*), but above all the analysis of his inner inclinations according to which he “operates from himself” in his environment and forms his “world-view” (*Weltanschauung*). Unlike objective psychology, which aims to be an exact science, philosophical anthropology intends to reveal the original rhythm of the life of the spirit, inasmuch as “it does not seek solely the truth concerning the nature of man, but claims a decision about what truth in general can mean” (M. Heidegger, *Die Idee einer philosophischen Anthropologie*, in *Kantstudien*).