DETERMINISM. — This is the conception of a strict, necessary, and inevitable dependence between the elements of a process of becoming that stand in a cause-and-effect relationship. Depending on whether the process occurs in the sphere of nature or in the life of the spirit, whether individual or collective, we may have various forms of d.: physical, psychological, ethical, economic, historical, etc. D., however, is by no means bound to a materialistic conception of being and of the spirit, but rather to the rigorous identification of cause and reason and to the consequent representation or conception of real becoming on the model of merely logical derivation in the relationship between principle and consequence. D. therefore represents the most explicit and demanding conception of the rationality of the universe to which science and philosophy aspire, and it appears in every period of the history of thought. The general postulate and principle of d. is that “every cause is necessarily followed by its effect”; and this entails: 1) the pre-existence or antecedence of the cause with respect to the effect; 2) its determinability or knowability as a cause, that is, the univocal and rigorous pre-existence of the effect in the cause; 3) hence the necessity of the process by which the effect is derived from the cause, so as to ensure the perfect rationality of being and therefore a science or knowledge of a rigorously logical-mathematical type. Thus, for d., contingency and chance are reduced to mere appearance, due to the provisional and deficient character of our knowledge and of our present means of investigation.
According to Democritus, physical becoming is subject to a total and rigorous necessity: πάντα τε κατ' ἀνάγκην γίνεσθαι, τῆς δίνης αἰτίνας οὔσης τῆς γενέσεως πάντων, ἦν ἀνάγκην λέγει (frg. A 1, Diels-Kranz, Die Fragmente der Forsokratiher, 5th ed., II, Berlin 1935, p. 84). It appears in a text by Plutarch: “The causes of bodies that are currently coming into being or dissolving had no beginning, but successively, from infinite time, all things absolutely—past, present, and future—are governed by necessity” (frg. A 39; trans. V. ALTIERI, Gli atomisti, Bari 1936, p. 87). Since atoms consist of rigorously geometric structures and move only through purely mechanical impulses, Democritus excludes chance (τ' αὐτόμικτον) entirely from nature and fortune (τύχη) from human life, as Aristotle polemicizes against him (Phys., II, 4, throughout). But this would lead to the strictest necessity, which excludes all contingency and accidentality from the world. Indeed, Aristotle adds, if this event occurs because another event occurs, and that one because yet another occurs, until one reaches a first event that does not occur by chance but by necessity, then everything will occur by necessity, beginning with the event that was caused as the first and continuing to that which is regarded as the effect” (Met., XI, 8, 1065 a 8 ff.). Aristotle’s criticism aimed to safeguard physical contingency, due to the fallibility of sublunary bodies, as well as the very freedom that is essential to responsibility for human action. Certainly under the influence of Aristotelian criticism, Epicurus abandoned Democritus’s rigid mechanistic d., admitting that atoms, in their fall, underwent a clinamen, thus leaving an opening for individual initiative (cf. Epicuri Ethica, fig. 7; Col., VIII, ed. C. Diano, Florence 1940, p. 41); the Stoics, meanwhile, based their moralism on the strictest concatenation of events, under the yoke of εὐαρχήνη.
It is certainly to Democritean mechanism that the conception Galileo formed of causality returns, according to the formula found in the Dialogo dei massimi sistemi: “If it is true that of an effect there is only one primary cause, and that between cause and effect there is a firm and constant connection, it is necessary that, whenever a firm and constant alteration is observed in the effect, there should be a firm and constant alteration in the cause” (Opere, ed. Naz., VII, Florence 1933, p. 471). In the new physics of Galileo-Newton, therefore, the d. of phenomena appears decomposed into a series of elementary actions exerted through spatial-temporal continuity upon the material point in motion, so that both the individual movements and their totality and resultant will always be strictly determined in every respect. This conception received its philosophical formulation in Leibniz’s principle of sufficient reason, to which, in its determinist structure, Kant’s principle of causality also remains faithful, formulated as the “second analogy of experience,” which is precisely the way of conceiving the succession of experience in time according to necessity. This conception received its most explicit formulation in Laplace: “Nous devons envisager l'état présent de l'univers comme l'effet de son état antérieur et comme la cause de celui qui va suivre”. The correspondence between antecedent and consequent states must be absolute: “Une intelligence qui, pour un instant donné, connaîtrait toutes les forces dont la nature est animée et la situation respective des études qui la composent, si d'ailleurs elle était assez vaste pour soumettre ces données à l'analyse, embrasserait dans la même formule les mouvements des plus grands corps de l'univers et ceux du plus léger atome; rien ne serait incertain pour elle, et l'avenir comme le passé serait présent à ses yeux” (Théorie analytique des probabilités, 3rd ed., Paris 1820, p. VII). This conception, which dominated the entire 19th century, was supported not only by materialism and positivism but also by rationalism and criticism (F. Enriquez). It was instead vigorously opposed by the “philosophy of contingency” advocated by Boutroux (preceded by Secrétan and Ravaisson), whose significance lies in the opposition of modern French philosophy to every form of abstract intellectualism and in the affirmation of the original freedom of spiritual life, which emerges above matter: this freedom crowns the dynamism of “spontaneity” found at the foundation of every being in different degrees and forms. The idea of “necessity,” like that of “force,” is derived from our spirit, from moral and aesthetic life, and is therefore a priori: “Elle serait le symbole le plus matériel de l'obligation morale et de l'attrait esthétique, c'est-à-dire de la nécessité consentie et sentie” (E. Boutroux, De la contingence des lois de la nature, 5th ed., Paris 1905, p. 169). The laws of nature are therefore not something absolute and self-subsisting, but represent a certain degree of the spirit’s penetration of matter, and not the reverse, as materialism maintained. Bergson and scholars of the philosophy of science such as G. Milhaud, J. Tannery, and H. Poincaré joined in this struggle against d., as did neo-idealism, which, especially in Italy, prevailed over materialist positivism.
In psychology, the principle of d. found considerable favor in the “doctrine of association,” both as an attempt to explain representational dynamism (v. IDEA, ASSOCIAZIONE delle) and as a hypothesis concerning the genesis and behavior of habits or operational complexes (e.g.,
behaviourism). Both psychoanalysis, in deriving conscious life from the unconscious sphere, and the Gestaltpsychologie of Wertheimer’s school, so long as it affirms the so-called “principle of isomorphism,” that is, the correspondence (and hence dependence) of “representational” and operative “forms” upon “physical forms,” or upon the physico-chemical structural conditions (the Quer-funktionen = “transverse connecting currents”: Wertheimer) of the nervous system, remain prisoners of d. It is well known, on the other hand, that the most recent physical investigation of infratomic microstructures, contrary to Laplace’s hypothesis, is increasingly directed towards an indeterminist conception, since, with Planck’s discovery of the quantum (h), physical energy has proved to be discontinuous (Heisenberg’s principle of indeterminacy). Yet the meaning of this indeterminism is keenly debated: that is, whether it is intrinsic to the development of the physical process as such, or whether it depends only on our experimental means and on our limited capacity to know the factors present in a process. In any case, the rigid mechanistic, Democritean-Galilean concept of nature and its laws proves inadequate both in the natural sciences and in the sciences of life, which instead accept the principle of “probability” and express the becoming of processes in the form of “statistical laws.”
Thus falls one of the most serious difficulties which the science of all times had sought to advance against the possibility of free will, which seemed to be a breach in causal d. Psychological d., in this more precise sense, maintained that the “choice” of the will was determined either by the conditions of the object, insofar as it is the greater good among those present (objective ontological d.: for example, in Leibniz), or by the conditions of the subject, insofar as choice is conceived as the resultant of the constellation of conscious or unconscious forces and motives operating in consciousness (psychological d.). Every conception of freedom that makes human action depend upon cosmic agents, e.g. the movement of the stars, must arrive at d.; this is an error which the author of the Errores philosophorum (that is, Egidio Romano according to J. Koch) attributes to Alkindi: «Erravit enim, quia simpliciter et absque condicione asseruit futura pendere ex condicione supercaelestium corporum» (J. Koch, Giles of Rome: Errores Philosophorum, trans. by J. O. Riedl, Milwaukee 1944, p. 46, 14-15). Economic d. is the conception that explains history and its crises of civilization exclusively in terms of economic conflicts, understood above all as “class struggle,” so that the economic factor is primary and determining in relation to all the others (moral, religious, scientific, artistic, etc.), as Marxism maintains, which by virtue of this hermeneutical principle has called itself “scientific socialism.” V. LIBERTÀ: MATERIALISMO.