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Summa Theologica, by St. Thomas Aquinas, [1947], at


We must now consider heresy: under which head there are four points of inquiry:

(1) Whether heresy is a kind of unbelief?

(2) Of the matter about which it is;

(3) Whether heretics should be tolerated?

(4) Whether converts should be received?

Whether heresy is a species of unbelief?

Objection 1: It would seem that heresy is not a species of unbelief. For unbelief is in the understanding, as stated above (Q[10], A[2]). Now heresy would seem not to pertain to the understanding, but rather to the appetitive power; for Jerome says on Gal. 5:19: [*Cf. Decretals xxiv, qu. iii, cap. 27] "The works of the flesh are manifest: Heresy is derived from a Greek word meaning choice, whereby a man makes choice of that school which he deems best." But choice is an act of the appetitive power, as stated above (FS, Q[13], A[1]). Therefore heresy is not a species of unbelief.

Objection 2: Further, vice takes its species chiefly from its end; hence the Philosopher says (Ethic. v, 2) that "he who commits adultery that he may steal, is a thief rather than an adulterer." Now the end of heresy is temporal profit, especially lordship and glory, which belong to the vice of pride or covetousness: for Augustine says (De Util. Credendi i) that "a heretic is one who either devises or follows false and new opinions, for the sake of some temporal profit, especially that he may lord and be honored above others." Therefore heresy is a species of pride rather than of unbelief.

Objection 3: Further, since unbelief is in the understanding, it would seem not to pertain to the flesh. Now heresy belongs to the works of the flesh, for the Apostle says (Gal. 5:19): "The works of the flesh are manifest, which are fornication, uncleanness," and among the others, he adds, "dissensions, sects," which are the same as heresies. Therefore heresy is not a species of unbelief.

On the contrary, Falsehood is contrary to truth. Now a heretic is one who devises or follows false or new opinions. Therefore heresy is opposed to the truth, on which faith is founded; and consequently it is a species of unbelief.

I answer that, The word heresy as stated in the first objection denotes a choosing. Now choice as stated above (FS, Q[13], A[3]) is about things directed to the end, the end being presupposed. Now, in matters of faith, the will assents to some truth, as to its proper good, as was shown above (Q[4], A[3]): wherefore that which is the chief truth, has the character of last end, while those which are secondary truths, have the character of being directed to the end.

Now, whoever believes, assents to someone's words; so that, in every form of unbelief, the person to whose words assent is given seems to hold the chief place and to be the end as it were; while the things by holding which one assents to that person hold a secondary place. Consequently he that holds the Christian faith aright, assents, by his will, to Christ, in those things which truly belong to His doctrine.

Accordingly there are two ways in which a man may deviate from the rectitude of the Christian faith. First, because he is unwilling to assent to Christ: and such a man has an evil will, so to say, in respect of the very end. This belongs to the species of unbelief in pagans and Jews. Secondly, because, though he intends to assent to Christ, yet he fails in his choice of those things wherein he assents to Christ, because he chooses not what Christ really taught, but the suggestions of his own mind.

Therefore heresy is a species of unbelief, belonging to those who profess the Christian faith, but corrupt its dogmas.

Reply to Objection 1: Choice regards unbelief in the same way as the will regards faith, as stated above.

Reply to Objection 2: Vices take their species from their proximate end, while, from their remote end, they take their genus and cause. Thus in the case of adultery committed for the sake of theft, there is the species of adultery taken from its proper end and object; but the ultimate end shows that the act of adultery is both the result of the theft, and is included under it, as an effect under its cause, or a species under its genus, as appears from what we have said about acts in general (FS, Q[18], A[7]). Wherefore, as to the case in point also, the proximate end of heresy is adherence to one's own false opinion, and from this it derives its species, while its remote end reveals its cause, viz. that it arises from pride or covetousness.

Reply to Objection 3: Just as heresy is so called from its being a choosing [*From the Greek [hairein], to cut off], so does sect derive its name from its being a cutting off [secando], as Isidore states (Etym. viii, 3). Wherefore heresy and sect are the same thing, and each belongs to the works of the flesh, not indeed by reason of the act itself of unbelief in respect of its proximate object, but by reason of its cause, which is either the desire of an undue end in which way it arises from pride or covetousness, as stated in the second objection, or some illusion of the imagination (which gives rise to error, as the Philosopher states in Metaph. iv; Ed. Did. iii, 5), for this faculty has a certain connection with the flesh, in as much as its act is independent on a bodily organ.

Whether heresy is properly about matters of faith?

Objection 1: It would seem that heresy is not properly about matters of faith. For just as there are heresies and sects among Christians, so were there among the Jews, and Pharisees, as Isidore observes (Etym. viii, 3,4,5). Now their dissensions were not about matters of faith. Therefore heresy is not about matters of faith, as though they were its proper matter.

Objection 2: Further, the matter of faith is the thing believed. Now heresy is not only about things, but also about works, and about interpretations of Holy Writ. For Jerome says on Gal. 5:20 that "whoever expounds the Scriptures in any sense but that of the Holy Ghost by Whom they were written, may be called a heretic, though he may not have left the Church": and elsewhere he says that "heresies spring up from words spoken amiss." [*St. Thomas quotes this saying elsewhere, in Sent. iv, D, 13, and TP, Q[16], A[8], but it is not to be found in St. Jerome's works.] Therefore heresy is not properly about the matter of faith.

Objection 3: Further, we find the holy doctors differing even about matters pertaining to the faith, for example Augustine and Jerome, on the question about the cessation of the legal observances: and yet this was without any heresy on their part. Therefore heresy is not properly about the matter of faith.

On the contrary, Augustine says against the Manichees [*Cf. De Civ. Dei xviii, 51]: "In Christ's Church, those are heretics, who hold mischievous and erroneous opinions, and when rebuked that they may think soundly and rightly, offer a stubborn resistance, and, refusing to mend their pernicious and deadly doctrines, persist in defending them." Now pernicious and deadly doctrines are none but those which are contrary to the dogmas of faith, whereby "the just man liveth" (Rom. 1:17). Therefore heresy is about matters of faith, as about its proper matter.

I answer that, We are speaking of heresy now as denoting a corruption of the Christian faith. Now it does not imply a corruption of the Christian faith, if a man has a false opinion in matters that are not of faith, for instance, in questions of geometry and so forth, which cannot belong to the faith by any means; but only when a person has a false opinion about things belonging to the faith.

Now a thing may be of the faith in two ways, as stated above (FP, Q[32], A[4]; FS, Q[1], A[6], ad 1; FS, Q[2], A[5]), in one way, directly and principally, e.g. the articles of faith; in another way, indirectly and secondarily, e.g. those matters, the denial of which leads to the corruption of some article of faith; and there may be heresy in either way, even as there can be faith.

Reply to Objection 1: Just as the heresies of the Jews and Pharisees were about opinions relating to Judaism or Pharisaism, so also heresies among Christians are about matter touching the Christian faith.

Reply to Objection 2: A man is said to expound Holy Writ in another sense than that required by the Holy Ghost, when he so distorts the meaning of Holy Writ, that it is contrary to what the Holy Ghost has revealed. Hence it is written (Ezech. 13:6) about the false prophets: "They have persisted to confirm what they have said," viz. by false interpretations of Scripture. Moreover a man professes his faith by the words that he utters, since confession is an act of faith, as stated above (Q[3], A[1] ). Wherefore inordinate words about matters of faith may lead to corruption of the faith; and hence it is that Pope Leo says in a letter to Proterius, Bishop of Alexandria: "The enemies of Christ's cross lie in wait for our every deed and word, so that, if we but give them the slightest pretext, they may accuse us mendaciously of agreeing with Nestorius."

Reply to Objection 3: As Augustine says (Ep. xliii) and we find it stated in the Decretals (xxiv, qu. 3, can. Dixit Apostolus): "By no means should we accuse of heresy those who, however false and perverse their opinion may be, defend it without obstinate fervor, and seek the truth with careful anxiety, ready to mend their opinion, when they have found the truth," because, to wit, they do not make a choice in contradiction to the doctrine of the Church. Accordingly, certain doctors seem to have differed either in matters the holding of which in this or that way is of no consequence, so far as faith is concerned, or even in matters of faith, which were not as yet defined by the Church; although if anyone were obstinately to deny them after they had been defined by the authority of the universal Church, he would be deemed a heretic. This authority resides chiefly in the Sovereign Pontiff. For we read [*Decret. xxiv, qu. 1, can. Quoties]: "Whenever a question of faith is in dispute, I think, that all our brethren and fellow bishops ought to refer the matter to none other than Peter, as being the source of their name and honor, against whose authority neither Jerome nor Augustine nor any of the holy doctors defended their opinion." Hence Jerome says (Exposit. Symbol [*Among the supposititious works of St. Jerome]): "This, most blessed Pope, is the faith that we have been taught in the Catholic Church. If anything therein has been incorrectly or carelessly expressed, we beg that it may be set aright by you who hold the faith and see of Peter. If however this, our profession, be approved by the judgment of your apostleship, whoever may blame me, will prove that he himself is ignorant, or malicious, or even not a catholic but a heretic."

Whether heretics ought to be tolerated?

Objection 1: It seems that heretics ought to be tolerated. For the Apostle says (2 Tim. 2:24, 25): "The servant of the Lord must not wrangle . . . with modesty admonishing them that resist the truth, if peradventure God may give them repentance to know the truth, and they may recover themselves from the snares of the devil." Now if heretics are not tolerated but put to death, they lose the opportunity of repentance. Therefore it seems contrary to the Apostle's command.

Objection 2: Further, whatever is necessary in the Church should be tolerated. Now heresies are necessary in the Church, since the Apostle says (1 Cor. 11:19): "There must be . . . heresies, that they . . . who are reproved, may be manifest among you." Therefore it seems that heretics should be tolerated.

Objection 3: Further, the Master commanded his servants (Mat. 13:30) to suffer the cockle "to grow until the harvest," i.e. the end of the world, as a gloss explains it. Now holy men explain that the cockle denotes heretics. Therefore heretics should be tolerated.

On the contrary, The Apostle says (Titus 3:10, 11): "A man that is a heretic, after the first and second admonition, avoid: knowing that he, that is such an one, is subverted."

I answer that, With regard to heretics two points must be observed: one, on their own side; the other, on the side of the Church. On their own side there is the sin, whereby they deserve not only to be separated from the Church by excommunication, but also to be severed from the world by death. For it is a much graver matter to corrupt the faith which quickens the soul, than to forge money, which supports temporal life. Wherefore if forgers of money and other evil-doers are forthwith condemned to death by the secular authority, much more reason is there for heretics, as soon as they are convicted of heresy, to be not only excommunicated but even put to death.

On the part of the Church, however, there is mercy which looks to the conversion of the wanderer, wherefore she condemns not at once, but "after the first and second admonition," as the Apostle directs: after that, if he is yet stubborn, the Church no longer hoping for his conversion, looks to the salvation of others, by excommunicating him and separating him from the Church, and furthermore delivers him to the secular tribunal to be exterminated thereby from the world by death. For Jerome commenting on Gal. 5:9, "A little leaven," says: "Cut off the decayed flesh, expel the mangy sheep from the fold, lest the whole house, the whole paste, the whole body, the whole flock, burn, perish, rot, die. Arius was but one spark in Alexandria, but as that spark was not at once put out, the whole earth was laid waste by its flame."

Reply to Objection 1: This very modesty demands that the heretic should be admonished a first and second time: and if he be unwilling to retract, he must be reckoned as already "subverted," as we may gather from the words of the Apostle quoted above.

Reply to Objection 2: The profit that ensues from heresy is beside the intention of heretics, for it consists in the constancy of the faithful being put to the test, and "makes us shake off our sluggishness, and search the Scriptures more carefully," as Augustine states (De Gen. cont. Manich. i, 1). What they really intend is the corruption of the faith, which is to inflict very great harm indeed. Consequently we should consider what they directly intend, and expel them, rather than what is beside their intention, and so, tolerate them.

Reply to Objection 3: According to Decret. (xxiv, qu. iii, can. Notandum), "to be excommunicated is not to be uprooted." A man is excommunicated, as the Apostle says (1 Cor. 5:5) that his "spirit may be saved in the day of Our Lord." Yet if heretics be altogether uprooted by death, this is not contrary to Our Lord's command, which is to be understood as referring to the case when the cockle cannot be plucked up without plucking up the wheat, as we explained above (Q[10], A[8], ad 1), when treating of unbelievers in general.

Whether the Church should receive those who return from heresy?

Objection 1: It would seem that the Church ought in all cases to receive those who return from heresy. For it is written (Jer. 3:1) in the person of the Lord: "Thou hast prostituted thyself to many lovers; nevertheless return to Me saith the Lord." Now the sentence of the Church is God's sentence, according to Dt. 1:17: "You shall hear the little as well as the great: neither shall you respect any man's person, because it is the judgment of God." Therefore even those who are guilty of the prostitution of unbelief which is spiritual prostitution, should be received all the same.

Objection 2: Further, Our Lord commanded Peter (Mat. 18:22) to forgive his offending brother "not" only "till seven times, but till seventy times seven times," which Jerome expounds as meaning that "a man should be forgiven, as often as he has sinned." Therefore he ought to be received by the Church as often as he has sinned by falling back into heresy.

Objection 3: Further, heresy is a kind of unbelief. Now other unbelievers who wish to be converted are received by the Church. Therefore heretics also should be received.

On the contrary, The Decretal Ad abolendam (De Haereticis, cap. ix) says that "those who are found to have relapsed into the error which they had already abjured, must be left to the secular tribunal." Therefore they should not be received by the Church.

I answer that, In obedience to Our Lord's institution, the Church extends her charity to all, not only to friends, but also to foes who persecute her, according to Mat. 5:44: "Love your enemies; do good to them that hate you." Now it is part of charity that we should both wish and work our neighbor's good. Again, good is twofold: one is spiritual, namely the health of the soul, which good is chiefly the object of charity, since it is this chiefly that we should wish for one another. Consequently, from this point of view, heretics who return after falling no matter how often, are admitted by the Church to Penance whereby the way of salvation is opened to them.

The other good is that which charity considers secondarily, viz. temporal good, such as life of the body, worldly possessions, good repute, ecclesiastical or secular dignity, for we are not bound by charity to wish others this good, except in relation to the eternal salvation of them and of others. Hence if the presence of one of these goods in one individual might be an obstacle to eternal salvation in many, we are not bound out of charity to wish such a good to that person, rather should we desire him to be without it, both because eternal salvation takes precedence of temporal good, and because the good of the many is to be preferred to the good of one. Now if heretics were always received on their return, in order to save their lives and other temporal goods, this might be prejudicial to the salvation of others, both because they would infect others if they relapsed again, and because, if they escaped without punishment, others would feel more assured in lapsing into heresy. For it is written (Eccles. 8:11): "For because sentence is not speedily pronounced against the evil, the children of men commit evils without any fear."

For this reason the Church not only admits to Penance those who return from heresy for the first time, but also safeguards their lives, and sometimes by dispensation, restores them to the ecclesiastical dignities which they may have had before, should their conversion appear to be sincere: we read of this as having frequently been done for the good of peace. But when they fall again, after having been received, this seems to prove them to be inconstant in faith, wherefore when they return again, they are admitted to Penance, but are not delivered from the pain of death.

Reply to Objection 1: In God's tribunal, those who return are always received, because God is a searcher of hearts, and knows those who return in sincerity. But the Church cannot imitate God in this, for she presumes that those who relapse after being once received, are not sincere in their return; hence she does not debar them from the way of salvation, but neither does she protect them from the sentence of death.

Reply to Objection 2: Our Lord was speaking to Peter of sins committed against oneself, for one should always forgive such offenses and spare our brother when he repents. These words are not to be applied to sins committed against one's neighbor or against God, for it is not left to our discretion to forgive such offenses, as Jerome says on Mat. 18:15, "If thy brother shall offend against thee." Yet even in this matter the law prescribes limits according as God's honor or our neighbor's good demands.

Reply to Objection 3: When other unbelievers, who have never received the faith are converted, they do not as yet show signs of inconstancy in faith, as relapsed heretics do; hence the comparison fails.

Next: Question. 12 - OF APOSTASY (TWO ARTICLES)