DETERMINISM. — It is the conception of a strict, necessary, and inevitable dependence among the elements of a process of becoming that stand in the relation of cause and effect. Depending on whether the process occurs in the realm of nature or in the life of the spirit—whether individual or collective—various forms of determinism may arise: physical, psychological, ethical, economic, historical, etc. Determinism, however, is not necessarily tied to a materialistic conception of being and spirit; rather, it is tied to the rigorous identification of cause and reason and to the consequent representation or conception of real becoming on the model of purely logical derivation in the relation of principle and consequence. Determinism thus represents the most explicit and demanding conception of the rationality of the universe, which science and philosophy aspire to, and it has appeared in all epochs of the history of thought.
The general postulate or principle of determinism is that “to every cause there necessarily follows its effect,” and this implies: 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) the necessity, therefore, of the process of derivation of the effect from the cause, so as to ensure the perfect rationality of being and thus a science or knowledge of a rigorously logical-mathematical type. Hence, for determinism, contingency and chance are reduced to mere appearances, due to the provisional and deficient nature of our knowledge and of our current “means of investigation.”
According to Democritus, physical becoming is subject to total and rigorous necessity: “nature and necessity bring about all things, the cause of the motion of all things being necessity” (frg. A. I, Diels-Kranz, *Die Fragmente der Vorsokratiker*, 5th ed., II, Berlin 1935, p. 84). A passage from Plutarch states: “The causes of bodies that are now being born or dissolved have had no beginning, but from infinite time all things, past, present, and future, are governed by necessity” (frg. A. 39; trans. V. ALTIERI, *Gli atomisti*, Bari 1936, p. 87). Since atoms are composed of rigorously geometric structures and move only through purely mechanical impulses, Democritus entirely excludes chance (*τ’αὐτόματον*) from nature and fortune (*τύχη*) from human life, as Aristotle polemically notes (Phys., II, 4, in its entirety). Yet this would seem to imply the most rigorous necessity, excluding all contingency and accident from the world. Indeed, Aristotle completes the argument: “If this fact occurs because another occurs, and this because yet another, up to a first that does not occur by chance but by necessity, then everything will occur by necessity, beginning from the fact that was caused as the first and up to that which is considered the effect” (Met., XII, 8, 1065 a 8 ff.). Aristotle’s critique aimed to safeguard physical contingency, arising from the defectibility of sublunary bodies, as well as the freedom essential to human responsibility in action. Under the influence of Aristotle’s critique, Epicurus abandoned Democritus’s rigid mechanistic determinism and admitted that atoms, in their fall, undergo a *clinamen*, thus leaving room for individual initiative (cf. *Epicuri Ethica*, frg. 7; Col., VIII, ed. C. Diano, Florence 1946, p. 41). Meanwhile, the Stoics grounded their moralism in the most rigid concatenation of events under the yoke of *heimarmene*.
It is certainly to Democritus’s mechanism that Galileo’s conception of causality returns, as expressed in the formula found in the *Dialogue Concerning the Two Chief World Systems*: “If it is true that for an effect there is only one primary cause and that between cause and effect there is a firm and constant connection, it necessarily follows that, whenever a firm and constant alteration is seen in the effect, there must be a firm and constant alteration in the cause” (*Opere*, ed. Naz., VII, Florence 1933, p. 471). In the new physics of Galileo and Newton, the determinism of phenomena is resolved into a series of elementary actions exerting continuous spatio-temporal influence on the moving material point, so that both individual movements and their totality and resultant are always strictly determined in every respect. This conception found its philosophical formulation in Leibniz’s principle of sufficient reason, to which Kant remained faithful in his formulation of the principle of causality as the “second analogy of experience,” which is precisely the way of conceiving the succession of experience in time according to necessity. The conception reached its most explicit formulation in Laplace: “We ought to regard the present state of the universe as the effect of its previous state and as the cause of that which is to follow.” The correspondence between antecedent and consequent states must be absolute: “An intelligence which, for a given instant, knew all the forces animating nature and the respective situation of all the entities composing it, if it were also vast enough to submit these data to analysis, would embrace in the same formula the movements of the largest bodies of the universe and those of the lightest atom; nothing would be uncertain for it, and the future as well as the past would be present to its eyes” (*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. Enriques). It was, however, 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 that emerges from matter. This freedom crowns the dynamism of “spontaneity” found at the root 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 thus is a priori: “It would be the most material symbol of moral obligation and aesthetic attraction, that is, of consented and felt necessity” (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-subsistent but represent a certain degree of penetration of matter by spirit, and not vice versa, as materialism would have II. In this struggle against determinism, Bergson and cultivators of the philosophy of science such as G. Milhaud, J. Tannery, and H. Poincaré joined forces, as did neo-idealism, which in Italy, especially, emerged victorious over materialist positivism.
In psychology the principle of determinism enjoyed considerable favor in the “doctrine of association,” both as an attempt to explain the dynamism of representation (v. IDEA, ASSOCIATION OF) and as a hypothesis regarding the genesis and behavior of habits or operative complexes (e.g., behaviorism). Both psychoanalysis, which derives conscious life from the unconscious sphere, and the Gestalt psychology of the Wertheimer school remain prisoners of determinism as long as it affirms the so-called “principle of isomorphism,” namely the correspondence (and hence dependence) of “representative and operative forms” on “physical forms” or on the physico-chemical structural conditions (the Querfunktionen = “transverse connecting currents”: Wertheimer) of the nervous system. It is well known, however, how the most recent physical investigation of infra-atomic micro-structures, contrary to Laplace’s hypothesis, is increasingly oriented toward an indeterministic conception inasmuch as, with Planck’s discovery of the quantum (h), physical energy has been revealed as discontinuous (Heisenberg’s principle of indeterminacy). Yet there is lively debate over the meaning of this indeterminism: whether it is intrinsic to the development of the physical process as such or whether it depends solely on our means of experimentation and our limited capacity to know the factors present in a process. In any case, the rigid mechanistic and Galilean-democratic concept of nature and its laws proves inadequate both in the natural sciences and in those of life, which instead accept the principle of “probability” and express the becoming of processes in the form of “statistical laws.”
Thus one of the gravest difficulties that science has at all times sought to advance against the possibility of free will—seeming to constitute a breach of causal determinism—is removed. Psychological determinism, in this more precise sense, held that the “choice” of the will was determined either by the conditions of the object, inasmuch as it is the greater good among those present (objective ontological determinism: e.g., in Leibniz), or by the conditions of the subject, inasmuch as the choice is conceived as the resultant of the constellation of conscious or unconscious forces and motives operating in consciousness (psychological determinism). Every conception of freedom that makes human action dependent on cosmic agents—e.g., the movement of the stars—must arrive at determinism; this error, which the author of the Errores philosophorum (that is, Giles of Rome, according to J. Koch) attributes to Al-Kindi, is expressed thus: “Erravit enim, quia simpliciter et absque condicione asseruit futura pendere ex condicione superacelestium corporum” (J. Koch, Giles of Rome: Errores Philosophorum, trans. by J. O. Riedl, Milwaukee 1944, p. 46, 14-15). Economic determinism 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 determinative with respect to all others (moral, religious, scientific, artistic, etc.), as Marxism maintains; in virtue of this hermeneutic principle it has called itself “scientific socialism.” V. LIBERTY; MARXISM.