Summa summae S. Thomae, Tomus III

Unbelief in general is the absence of faith¹. And it is either negative, privative, or contrary. Negative unbelief is the absence of faith in one who has heard nothing of the faith, or has not heard sufficiently. Privative unbelief is the absence of faith in one who has heard sufficiently of the faith and does not will to assent to it, without however asserting the contrary. Contrary unbelief is the absence of faith in one who, though sufficiently instructed concerning the faith, not only refuses to embrace it, but even asserts the contrary and maintains a positive error against the faith.

You will ask 1° whether unbelief is a sin.

I answer. 1°. Merely negative unbelief is not a sin, but a punishment of sin².

Proof. 1° Christ, Ioann., XV, 22, says of the Jews: If I had not come and spoken to them, they would not have sin. Expounding this, Aug., Tract. LXXXIX in Ioann., says that Christ speaks of the sin by which they did not believe in Christ. But Christ spoke to negative unbelievers neither by himself nor through his ministers, at least not sufficiently. 2° No one sins by omitting what he cannot do.

How shall they believe in him whom they have not heard? It is just as if he had said: « They cannot believe. » 3° This proposition, the 68th among those of Baius: « Purely negative unbelief, in those to whom Christ has not been preached, is a sin, » was condemned by St Pius V, October 1, 1567, by Gregory XIII, January 29, 1579, and by Urban VIII, March 6, 1641.

I answer. 2°. Privative and contrary unbelief is a sin³.

1° Because no one is condemned except on account of sin. But he who will not have believed shall be condemned, Marc., XVI, 16. 2° Because faith is the necessary medium unto salvation. Therefore he to whom it is sufficiently proposed is bound to accept it.

You will ask 2° whether all the works of unbelievers are sins.

I answer. Negatively⁴. We weighed this question expressly in the treatise on Grace, dissertation III, § 1. Look for it there.

You will ask 3° how many species of unbelief there are.

I answer. That three are commonly assigned, namely paganism, Judaism, and heresy⁵. For the sin of unbelief consists in resisting the faith. But one can resist the faith in three ways. For either one resists the faith which he has not yet professed himself to receive as true, and this is the unbelief of the pagans, who are so called from the pagi into which, expelled from the cities by command of the Christian emperors, they withdrew to worship their idols: before that time they were called gentiles. Or one resists the faith which he professed in figure, and this is the unbelief of the Jews. Or finally one resists the faith which he professed in the manifestation of the truth, and this is the unbelief of heretics.

I said: « Which he has professed himself to receive; » because for Judaism or heresy there seems not to be required that one have truly received the faith in figure or in manifested truth, but it suffices if he have outwardly professed himself to receive it. Hence unbaptized infants of heretics, who therefore never received the faith, are called heretics because in estimation they profess together with their parents the faith of Christ.

To paganism belong atheists, deists, and Mohammedans; because they have never professed themselves to receive the faith of Christ, whether in figure or in truth. For although the Mohammedans acknowledge Christ as a prophet, they do not acknowledge him as God.

Apostasy seems not to be distinguished from heresy except according to more and less; for the apostate abandons the whole faith which he professed, the heretic only a part: understand this objectively. Similarly other forms of unbelief can be reduced to one of the aforementioned.

[You will ask 4° whether unbelievers are to be compelled to the faith.

I answer. Those who have never received the faith, whether they be subject to Christian princes or not, are by no means to be compelled to embrace the faith; they can, however, be compelled not to impede the faith and the preaching of the faith by blasphemies, wicked persuasions, or open proclamations.

The first part is clear; because the Church has no jurisdiction over those who have not received the faith, according to that saying, I Cor., V, 12: What have I to do to judge those who are without? And the Council of Trent, session XIV, chapter 5, declares that « the Church exercises judgment upon no one who has not first entered her through the door of baptism. » Christian princes likewise have no jurisdiction over foreigners, but over subjects they have jurisdiction by which they govern them politically; this jurisdiction nevertheless does not include the right of compelling them to the faith. And although they can compel subjects to abandon idolatry, which is against the natural law, of which every prince is the guardian, their power nevertheless does not extend to the law of faith, which is of the supernatural order.

This conclusion is confirmed by the decisive words of Leo XIII, in the Encyclical Immortale Dei, November 1, 1885: « If, he says, the Church judges it unlawful that the various kinds of divine worship hold the same right as the true religion, she does not on that account condemn those moderators of commonwealths who, for the sake of obtaining some great good or preventing some great evil, patiently bear by custom and usage that each of these things hold a place in the state. — The Church likewise greatly takes care that no one be compelled to embrace the Catholic faith against his will; because, as Augustine wisely admonishes, Tract. XXVI in Ioann., n. 2, man cannot believe unless he is willing. »

The second part is also clear. For the Church has from Christ the command, and consequently the right, of preaching the Gospel in the whole world, Matth., XXVIII, 19. If therefore barbarians impede this preaching, Christian princes can, and at times must, wage war against them and subdue rebels, that they may guard the violated rights of the Church and defend the innocent, both those who have the right of preaching and those who have the right of hearing.]