MONISM. — From μόνος, one, it is, in the proper sense, every system that regards the multiplicity of things as apparent, resolving it into a fundamental and absolute unity. The term is due to Chr. Wolff: «Monistae dicuntur philosophus qui unum tantummodo substantiae genus admittunt» (Psych. ration., § 32). The meaning of m. is therefore first and foremost metaphysical, since it presents itself as a system for interpreting reality in its constitutive and resolving principle, both with regard to being and to activity.
On this level, m. defends the absolute unity of being and substance, dualism (v.) pluralism (v.) that admits an ultimate constitutive heterogeneity in the various orders or moments or values of reality. It therefore asserts the spirit (v.), soul (v.), being and activity, substance (v.) and its determinations, nature and consciousness (v.), physical laws and biological laws, intellect (v.), subject (v.), God (v.). The various qualifications of m. depend on the different conceptions of reality that are posited as the foundation and resolution of everything. For materialistic m., the only absolute reality is matter (v.) as the principle of force, energy, life, spirit, thought, and consciousness. Another expression of materialistic m. is energeticism (W. Ostwald, Die Energien, Leipzig 1908; V. DINAMISMO), insofar as it too resolves every reality and phenomenon in the materialistic principle, considered essentially as force. Naturalism (v.) and evolutionism, in their most rigorous meaning, are further determinations of materialistic m., elaborated from the predominantly dynamic point of view of that same material reality. Opposed to materialistic m. (but ultimately only on the systematic and phenomenal level, owing to the final resolution, common to both, of being and experience into absolute unity) is spiritualistic m. It is twofold: voluntaristic (or telistic) if it understands fundamental reality as tendency or Will; intellectualistic (or logical) if the only absolute reality is understood as Spirit, Thought, Intellect, Consciousness, Self-consciousness, subjective Act (idealism [v.], panlogism [v.], actualism [v.]). Spiritualistic m. may be conceived either
with a static meaning (the resolution of everything into an immutable spiritual Principle), or as emanationist (the world posited through a process of derivation from the spiritual principle), or as dialectical (reality as the very immanent process of spirit). Between materialistic m. and spiritualistic m. there may be placed (although here too the difference is only systematic) synthetic m. (or identity-based m.), which understands the one fundamental reality as an original indeterminate synthesis of matter and spirit; and ontological m., which abstracts from any original determination of reality, asserting absolute Unity on the transcendental plane of pure being. immanentism (v.) pantheism (v.) are monistic; pantheism differs from m. in general insofar as it recognizes a divine value and significance in all reality.
The further particular meanings of the term m. are for the most part, though not necessarily, derivations and applications of its fundamental metaphysical meaning. Physical m. defends the specific identity of substance within the sphere of the physical world: physical m. is therefore every system that asserts the original unity of matter, attributing the specific diversities of bodies solely to accidental determinations (quantitative variations and aggregations: atomism, mechanism, v.). hylozoism (v.), which conceive the world as a single organism informed by a living principle, whether naturalistic or divine, belong to physical m. Anthropological-psychological m. is the actualistic theory (v. ATTUALISMO) that maintains the identity of physiological and conscious phenomena, as expressions or parallel series of one and the same fundamental reality. It is also called the “theory of identity” and rejects the conception of the soul as a substance distinct from the body. Epistemological m. denies any essential difference between sensory knowledge and intellectual knowledge: in this sense empiricism (v.) nominalism (v.) are monistic. In a broader meaning, epistemological m. is the assertion of the absolute identity of subject and object. Ethical m. is autonomy (v.) of morality, whether in a spiritualistic sense (morality as a universal value immanent in reason) or in a materialistic-hedonistic sense (morality as the pure derivation and transformation of the egoistic, utilitarian, and altruistic tendencies of human nature, and as the product of feeling, custom, and mores). Social m. (opposed both to the atomistic and to the personalistic conception of society) posits the State as the supreme value in relation to individuals and therefore as the sole measure of law, the source and terminus of every right and duty (v. INDIVIDUALISMO; PERSONALISMO; SOCIETÀ). Historical m. history (v.) as the necessary process of a single absolute reality, excluding every real indeterminacy or self-determination of human freedom.
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MONICO, JACOPO — Portrait, engraving — Vatican Library.
impersonal of which the world is merely a manifestation. The first Greek philosophers who attempted to reduce nature to a single principle (ἀρχὴ φύσεως) are monists: Thales, Anaximenes, Anaximander («infinitatem naturae dixit esse a qua omnia gignereatur»: F. G. A. Mullach, Fragm. philosophorum graec., I, p. 237), Heraclitus (op. cit., p. 312 b.; cf. Aristotle, Met., I, 3). As far as can be inferred from the fragments, the doctrine of the Eleatics is monistic. Xenophanes identifies God, the one-all (ἐν καὶ πάν), with the world (theological m.); everything therefore goes back to the identical and «is resolved into a single nature» (μῶν εἰς φύσιν: Sextus Empiricus, Pyrrh. Hypot., I, 224; cf. Plato, Soph., 242 d). For Parmenides, being is ungenerated, immortal, complete, unitary, immobile, everlasting (οὐλῶν, μονογενὲς τὰ καὶ ἀτρεμὲς ἠδ' ἀτέλαστον: Mullach, op. cit., p. 120, 60; cf. Plato, Soph., 244 e). There is no origin, multiplicity, or becoming in being, and being and thinking are identical: τὸ γὰρ αὐτὸ νοῦν ἐστὶν τὰ καὶ εἶναι (Mullach, op. cit., p. 118, 40). Parmenides’ ontological m. resolves itself into materialism through the identification of being with corporeality (το πλῶν).
Monists in the materialistic sense are the atomists (Democritus, Leucippus: cf. Aristotle, Phys., I, 4, 5, Met., I, 8; Epicurus, Lucretius). The Stoics, dualists in ethics (the opposition between virtue and passion, sense and reason), defend a metaphysical m.: the λόγος (reason) is the universal reality that vivifies and unifies the universe: «Dei vero substantiam Zeno quidem ait mundum totum atque coelum» (Diogenes Laertius, VII, 1, 148). Plotinus (v.) also tends toward spiritualistic m., insofar as matter itself seems to have to be conceived as an emanation of the One. Expressions in a pantheistic sense are found in Scotus Eriugena (v.), even though in the end he seems to free himself from a genuine m., and in David of Dinant. A form of anthropological m. is offered by Averroës’ (v.) doctrine of the unity of the intellect. Renaissance philosophy, with its Neoplatonic and Stoic derivations and dependent upon the universe (v.), returns to the immanence of the «divine force» in nature. BRUGNATO (v.), God is the formal cause and internal principle of the world, which expresses aspects and forms from within itself; and it is God’s one life that manifests itself in all the worlds (Della causa principio e uno, II, ed. G. Gentile, Opere italiane, I, 2nd ed., Bari 1925, pp. 178 ff.). Similarly Paracelsus, V. WEINGARTEN, G. C. Vanini, J. Böhme (Morgenrät, chaps. 2–3). In modern philosophy, Berkeley’s (v.) immaterialism presents a form of anthropological m.: man is spirit alone; the body (and matter in general) is pure representation. Metaphysical m. Spinoza (v.), for whom thought and extension are mere manifestations of the one divine substance: «substantia cogitata et substantia extensa una eademque est substantia» (Ethica, part 2, prop. 6, scholium; ed. G. Gentile, 2nd ed., Bari 1933, p. 53; cf. pp. 4, 6). Materialistic m. is defended by Cl. Helvétius, D. Diderot (Pensées sur l'interprétation de la nature, London 1754), J. O. La Mettrie (L'homme machine, Paris 1748), P. H. Holbach (Système de la nature, London [Amsterdam or Leiden] 1770), P. J. Cabanis (Rapports du physique et du moral de l'homme, Paris 1802), J. Moleschott (Der Kreislauf des Lebens, Mainz 1852), L. Büchner (Kraft und Stoff, Frankfurt 1855), C. Vogt, H. Czobło (Köhlerglaube und Wissenschaft, Giessen 1854; Vorlesungen über den Menschen..., ibid. 1863); and by Darwinian evolutionism, particularly by E. Haeckel (v.). For Haeckel (whose system may be regarded as a synthesis of Spinoza, Bruno, and Darwin), the substance of the world is at once God and nature and has matter and force as its attributes. Consequently, every spiritual order that would posit itself as distinct from and transcendent to the order and finality of the body is excluded (Die Welträtsel, chaps. 18–19). Similarly Haeckel, H. Münsterberg (Grundzüge der Psychologie, Leipzig 1900), Th. Ziehen (Gehirn und Seelenleben, ibid. 1902). Post-Kantian idealism is monistic. Schelling (v.), reality is the inner process of the absolute as an original principle and infinite tendency (imbued with Bruno and Spinoza), in whose identity every distinction is resolved. Hegel (v.), multiplicity is a purely dialectical moment in the becoming of the one and supreme reality, the idea: «only the absolute idea is being, life that does not pass away, truth conscious of itself, and is the whole truth» (La scienza della logica, Italian translation by A. Moni, III, Bari 1925, p. 305). The conception of E. V. Hartmann (v.) is monistic, according to which Unity, while expressing itself through its dynamic functions in a multiplicity of individuals, remains immanent in them; as is that of A. SCHOPENHAUER, ARTHUR (v.), for whom the world and man and all their phenomenal manifestations are expressions of the one fundamental reality, the Will (Wille zur Leben). Likewise A. Fouillée (v.), who admits the fundamental identity of nature and thought insofar as the will, dispersed throughout the world and in eternal expansion, reflects upon itself, concentrating and becoming conscious in man. L. Feuerbach’s dialectical materialism (Gottheit, Freiheit u. Unsterblichkeit, Leipzig 1886) and Marxism are monistic; the latter is characterized by the affirmation of the exclusively naturalistic-economic significance of the world of spirit. Psychophysical anthropological m. is defended by G. Fechner (Elemente der Psychophysik, Leipzig 1860: the «physical» is the external aspect, the «psychic» the internal aspect of a single reality), F. Paulsen, W. Wundt, and also by H. Taine, A. Bain, Fr. Jodl, H. Ebbinghaus, H. Spencer, who regard the «physical» and the «psychic» as manifestations of a further reality (neo-Spinozism). For Spencer, consciousness and matter are «pure symbols of a Power forever and absolutely unknown to us» (Princ. of psychology, no. 63). Gentilian actualism is monistic: «the finite thing is always the very reality of God» and the world «an eternal theogony that is fulfilled in the intimacy of our being» (Teoria gener. dello spirito come atto puro, 5th ed., Florence 1938, p. 265). Existentialism (v.), too, in its atheistic and agnostic forms, is fundamentally inspired by monism.
In Germany, the association Monistenbund enjoyed wide diffusion during the first decades of the twentieth century (founded at Jena in 1906; before the First World War it had approximately 7,000 members in 45 sections; cf. Monistenbund, in LThK, VII, cols. 281–82). The purpose of the Monistenbund, avowedly anti-Christian and anti-Catholic, was to disseminate the naturalistic conception, excluding any supernatural factor from science and philosophy. Less radical was the journal The monist (founded by P. Carus, Chicago, January 1891), which intended to defend the unity and harmony of all truths and hence also the reconciliation of science and faith. Nevertheless, it too accepted the fundamental monist idea of an inseparable unity of the whole, and in science Haeckel’s monistic conception.
Monism, considered here in its fundamental, metaphysical expression, is radically irreconcilable with Christianity. It entails, in fact, the denial of God’s transcendence and personality and therefore, besides obviously opposing the very possibility of a supernatural order, eliminates the sole valid foundation of religion, of a universal ethic, and of an authentic spiritualistic conception of life. Understood in both its materialistic and idealistic senses, monism is unable to preserve the Christian concepts of freedom, responsibility, obligation, conscience, and sin (v. le rispettive voci). From a philosophical point of view, it must be observed that multiplicity and the irreducibility of personal consciousnesses, of which the entire human world is a clear manifestation, find no real explanation in monism. Even within the order of lower nature, the plurality of living and non-living structures manifests, on the empirical-phenomenal plane, a specificity so profound that its adequate reason can lie only in a diversification reaching the ontological plane of being itself. «È impossibile risolvere tutte le cose in unità» (ἀδύνατον φαίνεται τὰ ἕνα ἐν εἶναι: Aristotle, Phys., I, 3, 186 a 4; cf. De generat. et corrupt., I, 1, and Plato, Soph., 244 b). It should further be noted that monism, enclosing the becoming of reality within itself, is irrationalism (v.) which derives act (v.) from potency, the determinate from the indeterminate, and consequently being from non-being. These are conclusions that Christian thought is able to avoid by positing the ontological distinction between the absolute and the relative, being through itself and participated being. This does not mean that the positive demand of monism—namely, the requirement to explain and reduce all reality to a single Principle, in opposition to the extreme expressions of dualism—is not fully preserved in Christian thought. Here, however, the unity of being is attained not through identity, but on the basis of the relation of causality, the sole dialectical moment which, by grounding the derivation of the relative from the absolute, at once opposes its resolution in that same absolute and guarantees its own consistency on the plane of being. V. anche ai singoli autori and, in addition, the entries CONOSCENZA; DIO; ENTE-ESSERE; PANTEISMO; SOSTANZA.