PHYSICAL PREVENTION. – It is the prior or immediate concurrence or influence of God upon the activity of every creature, and especially upon human action, even when it is free, according to the doctrine of St Thomas.
I. HISTORY
The question of the relationship between God and the activity of created nature has had a varied development within Christian thought. In the time of St Thomas two opposing currents prevailed: one which harked back to St Augustine and Jewish philosophy (Avicebron in the book *Fons vitae*) and maintained a theocentric position, according to which the action of the creature, both in its execution and in its specification, depends exclusively upon the will of God; the other, tinged with naturalism, came from Arabic philosophy (Avicenna, Averroes) and sought to explain every activity of the creature by means of its natural energies, without divine intervention. Evidently the first opinion deprived nature of its intrinsic operative capacity and made of the natural agent not a true cause in itself, but an occasion which God would use to produce a determinate effect (almost an anticipation of Malebranche’s occasionalism). The second opinion, on the other hand, exalted nature beyond its due, to the point of withdrawing it from God’s dominion. St Thomas perceived the incongruity of the one and the absurdity of the other, and, starting from the concept of creation—which subordinates entirely the being of the creature in its origin and in its conservation—he established, in the light of reason and Revelation, that nature, with its faculties, is intrinsically ordered and proportioned to determinate effects, but just as it cannot exist for even an instant by itself, so it cannot pass into action by itself, but requires the influence of the First Cause. In other words, St Thomas sees in every created agent, man not excepted, a being “in potency,” which cannot give itself actuality without the intervention of the Pure Act, which is God. By this path he arrives at the theory of physical prevention as the divine influence which determines the passage from potency to act, and thus as a divine action which, in the order of causality, precedes and physically actualizes every created agent. In *De potentia* (q. 3, a. 7) St Thomas lucidly expounds his thought, saying that God is the cause of every action of the creature both because He gives it being with operative virtue and preserves it in being, and because He applies that virtue to the action in such a way that the natural agent operates as an instrumental cause of God, the principal cause.Within the Dominican Order, Durandus opposed this doctrine, limiting God’s action to the creation and conservation of nature and its faculties, which would then pass into action by themselves (mediate concurrence).
In the 16th century a heated controversy flared up between Dominicans and Jesuits concerning the natural and supernatural action of God upon creatures, and especially upon the free will of man (v. BANÉZ; MOLINISM). The Jesuit Luis de Molina (in his work *Concordia*, 1588) proposed the opinion according to which God would intervene in human activity not by preventing it, but by accompanying the will with His influence, which would remain the arbiter of its action and capable of using the concurrence offered by God both for good and for evil. In this way God would stand alongside the creature without determining it, but ready to aid it whenever it moved to action. Molina thus upheld a divine concurrence that was not prior, but “simultaneous.”
Against him rose up Domingo Báñez of the Order of Preachers, who, appealing to St Thomas, demonstrated that God’s influence upon the creature, and upon man in particular, is immediate and prior, indeed is efficaciously determinative of every single act, even a free one, in such a way that the will is not only moved by God to act, but is “predetermined” physically to this or that particular act (D. Báñez, *Scholastica commentaria in primam partem Angelici Doctoris*, Salamanca 1584 and 1588; id., *in secundam secundæ*, ibid. 1584 and 1594). The controversy, after some four centuries, is still alive in the opposing schools, which reproach one another with shortcomings and compromises: the Molinists point to the danger to human freedom in Báñez’s position, while the Thomists denounce in the Molinist position a derogation of God’s dominion over man.
In recent times various attempts at reconciliation between the opposing systems have been made, giving rise to the so-called “syncretism.”
II. THEOLOGY
From the doctrinal point of view, the genuine thought of St Thomas must be made clear, for it gathers the voice of sound tradition and has the suffrage of the Church’s magisterium, which, however, has not hitherto wished to settle the controversy and leaves Thomists and Molinists free to debate. St Thomas, in his theory, follows a strictly metaphysical line: only God is Being by essence, while all creatures receive being from Him. If the creature receives being, and therefore is not its own being, neither is it its own acting; but as in it action is distinct from its nature or essence (Sum. Theol., I, q. 61, a. 1; q. 3, a. 4; *De ente et essentia*, chaps. 5–6; as regards action, Sum. Theol., I, q. 54, a. 1; *Contra Gentiles*, III, chap. 70 and elsewhere often), God and creature are not two coordinate causes, but the one (the creature) is subordinate to the other (God), as the instrument to the principal cause (*Contra Gentiles*, I, chap. 44; III, chap. 67 and IV, chap. 41, besides *De potentia*, q. 3, a. 7 already cited). The profound reason for God’s intervention in the action of the creature is, as has been said, the potential state of every secondary cause; then this intervention is required by the fact that in every action of nature an effect is realized, which is a new mode of being; one touches upon being, which, as an effect of universal character, demands a universal cause, such as only God is. From these principles the necessity of divine physical prevention in all the activity of created nature follows, and therefore also in that of man.The Molinist position does not seem to take account of these metaphysical principles when it admits the possibility in the creature of passing into action without being intrinsically moved by God. Nevertheless, the Molinists are right to oppose the concept of a physical prevention that would also be predetermination to this or that particular act. Everyone sees in such predetermination a danger of compromising human freedom, which is usually defined as self-determination.
Returning to St. Thomas, it must be acknowledged that he unreservedly admits the physical premotion, but he does not speak of a predetermination “to one” of the will under the divine impulse. Indeed, there are texts from which it appears that St. Thomas constantly opposes necessity to freedom and equates the former with determination “to one,” the latter with active indeterminacy or indifference in the face of particular goods: “The first cause does not act upon the will in such a way as to determine it necessarily to one, as it determines nature; therefore the determination of the act is left in the power of reason and will” (De potentia, q. 3, a. 7, ad 13, cf. De malo, q. 6, art. un., ad 3). In the Summa Theologiae, I-II, q. 9, a. 6, ad 3, the holy Doctor summarizes his thought in these precise terms: “God moves the human will as the universal mover toward the universal object of the will, which is the good, and without this universal motion man cannot will anything; but man, through reason, determines himself to will this or that.” Thus the specific determination of the act, in which freedom is manifested, is entrusted to reason and will. In reality, the free act is due to the will and reason together, though in different respects: as realization (St. Thomas says “exercise”) it depends on the will, but as specification it depends on the object presented by the intellect. The divine motion properly unfolds along the line of exercise: with regard to specification, God concurs insofar as He moves the intellect to present the object that appeals to the will, which is free to adhere to it or to reject it (cf. Summa Theologiae, I-II, q. 9, a. 1 and q. 10, a. 2).
Other theologians suggest other forms of mitigation of the physical premotion, always with the concern of safeguarding human freedom under the divinely willed influence generally admitted. But it must be confessed that the problem of reconciling freedom with the physical premotion, and with efficacious grace, touches upon the realm of mystery, and thus no theological system will ever succeed in resolving it adequately.