Summa Th. II-II EN Qu.9
We must now consider the gift of knowledge, under which head there are four points of inquiry:
(1) Whether knowledge is a gift?
(2) Whether it is about Divine things?
(3) Whether it is speculative or practical?
(4) Which beatitude responds to it?
Objection: 1. It would seem that knowledge is not a gift. For the gifts of the Holy Ghost surpass the natural faculty. But knowledge implies an effect of natural reason: for the Philosopher says (Poster. i, 2) that a "demonstration is a syllogism which produces knowledge." Therefore knowledge is not a gift of the Holy Ghost.
2. Further, the gifts of the Holy Ghost are common to all holy persons, as stated above (Question , Article ; FS, Question , Article ). Now Augustine says (De Trin. xiv, 1) that "many of the faithful lack knowledge though they have faith." Therefore knowledge is not a gift.
3. Further, the gifts are more perfect than the virtues, as stated above (FS, Question , Article ). Therefore one gift suffices for the perfection of one virtue. Now the gift of understanding responds to the virtue of faith, as stated above (Question , Article ). Therefore the gift of knowledge does not respond to that virtue, nor does it appear to which other virtue it can respond. Since, then, the gifts are perfections of virtues, as stated above (FS, Question , Articles ,2), it seems that knowledge is not a gift.
On the contrary Knowledge is reckoned among the seven gifts (Is 11,2).
I answer that Grace is more perfect than nature, and, therefore, does not fail in those things wherein man can be perfected by nature. Now, when a man, by his natural reason, assents by his intellect to some truth, he is perfected in two ways in respect of that truth: first, because he grasps it; secondly, because he forms a sure judgment on it.Accordingly, two things are requisite in order that the human intellect may perfectly assent to the truth of the faith: one of these is that he should have a sound grasp of the things that are proposed to be believed, and this pertains to the gift of understanding, as stated above (Question , Article ): while the other is that he should have a sure and right judgment on them, so as to discern what is to be believed, from what is not to be believed, and for this the gift of knowledge is required.
Reply to Objection: 1. Certitude of knowledge varies in various natures, according to the various conditions of each nature. Because man forms a sure judgment about a truth by the discursive process of his reason: and so human knowledge is acquired by means of demonstrative reasoning. On the other hand, in God, there is a sure judgment of truth, without any discursive process, by simple intuition, as was stated in the FP, Question , Article ; wherefore God's knowledge is not discursive, or argumentative, but absolute and simple, to which that knowledge is likened which is a gift of the Holy Ghost, since it is a participated likeness thereof.
2. A twofold knowledge may be had about matters of belief. One is the knowledge of what one ought to believe by discerning things to be believed from things not to be believe: in this way knowledge is a gift and is common to all holy persons. The other is a knowledge about matters of belief, whereby one knows not only what one ought to believe, but also how to make the faith known, how to induce others to believe, and confute those who deny the faith. This knowledge is numbered among the gratuitous graces, which are not given to all, but to some. Hence Augustine, after the words quoted, adds: "It is one thing for a man merely to know what he ought to believe, and another to know how to dispense what he believes to the godly, and to defend it against the ungodly."
3. The gifts are more perfect than the moral and intellectual virtues; but they are not more perfect than the theological virtues; rather are all the gifts ordained to the perfection of the theological virtues, as to their end. Hence it is not unreasonable if several gifts are ordained to one theological virtue.
Objection: 1. It would seem that the gift of knowledge is about Divine things. For Augustine says (De Trin. xiv, 1) that "knowledge begets, nourishes and strengthens faith." Now faith is about Divine things, because its object is the First Truth, as stated above (Question , Article ). Therefore the gift of knowledge also is about Divine things.
2. Further, the gift of knowledge is more excellent than acquired knowledge. But there is an acquired knowledge about Divine things, for instance, the science of metaphysics. Much more therefore is the gift of knowledge about Divine things.
3. Further, according to Rm 1,20, "the invisible things of God . . . are clearly seen, being understood by the things that are made." If therefore there is knowledge about created things, it seems that there is also knowledge of Divine things.
On the contrary Augustine says (De Trin. xiv, 1): "The knowledge of Divine things may be properly called wisdom, and the knowledge of human affairs may properly receive the name of knowledge."
I answer that A sure judgment about a thing formed chiefly from its cause, and so the order of judgments should be according to the order of causes. For just as the first cause is the cause of the second, so ought the judgment about the second cause to be formed through the first cause: nor is it possible to judge of the first cause through any other cause; wherefore the judgment which is formed through the first cause, is the first and most perfect judgment.Now in those things where we find something most perfect, the common name of the genus is appropriated for those things which fall short of the most perfect, and some special name is adapted to the most perfect thing, as is the case in Logic. For in the genus of convertible terms, that which signifies "what a thing is," is given the special name of "definition," but the convertible terms which fall short of this, retain the common name, and are called "proper" terms.Accordingly, since the word knowledge implies certitude of judgment as stated above (Article ), if this certitude of the judgment is derived from the highest cause, the knowledge has a special name, which is wisdom: for a wise man in any branch of knowledge is one who knows the highest cause of that kind of knowledge, and is able to judge of all matters by that cause: and a wise man "absolutely," is one who knows the cause which is absolutely highest, namely God. Hence the knowledge of Divine things is called "wisdom," while the knowledge of human things is called "knowledge," this being the common name denoting certitude of judgment, and appropriated to the judgment which is formed through second causes. Accordingly, if we take knowledge in this way, it is a distinct gift from the gift of wisdom, so that the gift of knowledge is only about human or created things.
Reply to Objection: 1. Although matters of faith are Divine and eternal, yet faith itself is something temporal in the mind of the believer. Hence to know what one ought to believe, belongs to the gift of knowledge, but to know in themselves the very things we believe, by a kind of union with them, belongs to the gift of wisdom. Therefore the gift of wisdom corresponds more to charity which unites man's mind to God.
2. This argument takes knowledge in the generic acceptation of the term: it is not thus that knowledge is a special gift, but according as it is restricted to judgments formed through created things.
3. As stated above (Question , Article ), every cognitive habit regards formally the mean through which things are known, and materially, the things that are known through the mean. And since that which is formal, is of most account, it follows that those sciences which draw conclusions about physical matter from mathematical principles, are reckoned rather among the mathematical sciences, though, as to their matter they have more in common with physical sciences: and for this reason it is stated in Phys. ii, 2 that they are more akin to physics. Accordingly, since man knows God through His creatures, this seems to pertain to "knowledge," to which it belongs formally, rather than to "wisdom," to which it belongs materially: and, conversely, when we judge of creatures according to Divine things, this pertains to "wisdom" rather than to "knowledge."
Objection: 1. It would seem that the knowledge, which is numbered among the gifts, is practical knowledge. For Augustine says (De Trin. xii, 14) that "knowledge is concerned with the actions in which we make use of external things." But the knowledge which is concerned about actions is practical. Therefore the gift of knowledge is practical.
2. Further, Gregory says (Moral. i, 32): "Knowledge is nought if it hath not its use for piety . . . and piety is very useless if it lacks the discernment of knowledge." Now it follows from this authority that knowledge directs piety. But this cannot apply to a speculative science. Therefore the gift of knowledge is not speculative but practical.
3. Further, the gifts of the Holy Ghost are only in the righteous, as stated above (Question , Article ). But speculative knowledge can be also in the unrighteous, according to Jc 4,17: "To him . . . who knoweth to do good, and doth it not, to him it is a sin." Therefore the gift of knowledge is not speculative but practical.
On the contrary Gregory says (Moral. i, 32): "Knowledge on her own day prepares a feast, because she overcomes the fast of ignorance in the mind." Now ignorance is not entirely removed, save by both kinds of knowledge, viz. speculative and practical. Therefore the gift of knowledge is both speculative and practical.
I answer that As stated above (Question , Article ), the gift of knowledge, like the gift of understanding, is ordained to the certitude of faith. Now faith consists primarily and principally in speculation, in as much as it is founded on the First Truth. But since the First Truth is also the last end for the sake of which our works are done, hence it is that faith extends to works, according to Ga 5,6: "Faith . . . worketh by charity."The consequence is that the gift of knowledge also, primarily and principally indeed, regards speculation, in so far as man knows what he ought to hold by faith; yet, secondarily, it extends to works, since we are directed in our actions by the knowledge of matters of faith, and of conclusions drawn therefrom.
Reply to Objection: 1. Augustine is speaking of the gift of knowledge, in so far as it extends to works; for action is ascribed to knowledge, yet not action solely, nor primarily: and in this way it directs piety.
2. Hence the Reply to the Second Objection is clear.
3. As we have already stated (Question , Article ) about the gift of understanding, not everyone who understands, has the gift of understanding, but only he that understands through a habit of grace: and so we must take note, with regard to the gift of knowledge, that they alone have the gift of knowledge, who judge aright about matters of faith and action, through the grace bestowed on them, so as never to wander from the straight path of justice. This is the knowledge of holy things, according to Sg 10,10: "She conducted the just . . . through the right ways . . . and gave him the knowledge of holy things."
Objection: 1. It would seem that the third beatitude, "Blessed are they that mourn," does not correspond to the gift of knowledge. For, even as evil is the cause of sorrow and grief, so is good the cause of joy. Now knowledge brings good to light rather than evil, since the latter is known through evil: for "the straight line rules both itself and the crooked line" (De Anima i, 5). Therefore the aforesaid beatitude does not suitably correspond to the gift of knowledge.
2. Further, consideration of truth is an act of knowledge. Now there is no sorrow in the consideration of truth; rather is there joy, since it is written (Sg 8,16): "Her conversation hath no bitterness, nor her company any tediousness, but joy and gladness." Therefore the aforesaid beatitude does not suitably correspond with the gift of knowledge.
3. Further, the gift of knowledge consists in speculation, before operation. Now, in so far as it consists in speculation, sorrow does not correspond to it, since "the speculative intellect is not concerned about things to be sought or avoided" (De Anima iii, 9). Therefore the aforesaid beatitude is not suitably reckoned to correspond with the gift of knowledge.
On the contrary Augustine says (De Serm. Dom. in Monte iv): "Knowledge befits the mourner, who has discovered that he has been mastered by the evil which he coveted as though it were good."
I answer that Right judgment about creatures belongs properly to knowledge. Now it is through creatures that man's aversion from God is occasioned, according to Sg 14,11: "Creatures . . . are turned to an abomination . . . and a snare to the feet of the unwise," of those, namely, who do not judge aright about creatures, since they deem the perfect good to consist in them. Hence they sin by placing their last end in them, and lose the true good. It is by forming a right judgment of creatures that man becomes aware of the loss (of which they may be the occasion), which judgment he exercises through the gift of knowledge.Hence the beatitude of sorrow is said to correspond to the gift of knowledge.
Reply to Objection: 1. Created goods do not cause spiritual joy, except in so far as they are referred to the Divine good, which is the proper cause of spiritual joy. Hence spiritual peace and the resulting joy correspond directly to the gift of wisdom: but to the gift of knowledge there corresponds, in the first place, sorrow for past errors, and, in consequence, consolation, since, by his right judgment, man directs creatures to the Divine good. For this reason sorrow is set forth in this beatitude, as the merit, and the resulting consolation, as the reward; which is begun in this life, and is perfected in the life to come.
2. Man rejoices in the very consideration of truth; yet he may sometimes grieve for the thing, the truth of which he considers: it is thus that sorrow is ascribed to knowledge.
3. No beatitude corresponds to knowledge, in so far as it consists in speculation, because man's beatitude consists, not in considering creatures, but in contemplating God. But man's beatitude does consist somewhat in the right use of creatures, and in well-ordered love of them: and this I say with regard to the beatitude of a wayfarer. Hence beatitude relating to contemplation is not ascribed to knowledge, but to understanding and wisdom, which are about Divine things.
In due sequence we must consider the contrary vices: first, unbelief, which is contrary to faith; secondly, blasphemy, which is opposed to confession of faith; thirdly, ignorance and dulness of mind, which are contrary to knowledge and understanding.
As to the first, we must consider (1) unbelief in general; (2) heresy; (3) apostasy from the faith.
Under the first head there are twelve points of inquiry:
(1) Whether unbelief is a sin?
(2) What is its subject?
(3) Whether it is the greatest of sins?
(4) Whether every action of unbelievers is a sin?
(5) Of the species of unbelief;
(6) Of their comparison, one with another;
(7) Whether we ought to dispute about faith with unbelievers?
(8) Whether they ought to be compelled to the faith?
(9) Whether we ought to have communications with them?
(10) Whether unbelievers can have authority over Christians?
(11) Whether the rites of unbelievers should be tolerated?
(12) Whether the children of unbelievers are to be baptized against their parents' will?
Objection: 1. It would seem that unbelief is not a sin. For every sin is contrary to nature, as Damascene proves (De Fide Orth. ii, 4). Now unbelief seems not to be contrary to nature; for Augustine says (De Praedest. Sanct. v) that "to be capable to having faith, just as to be capable of having charity, is natural to all men; whereas to have faith, even as to have charity, belongs to the grace of the faithful." Therefore not to have faith, which is to be an unbeliever, is not a sin.
2. Further, no one sins that which he cannot avoid, since every sin is voluntary. Now it is not in a man's power to avoid unbelief, for he cannot avoid it unless he have faith, because the Apostle says (Rm 10,14): "How shall they believe in Him, of Whom they have not heard? And how shall they hear without a preacher?" Therefore unbelief does not seem to be a sin.
3. Further, as stated above (FS, Question , Article ), there are seven capital sins, to which all sins are reduced. But unbelief does not seem to be comprised under any of them. Therefore unbelief is not a sin.
On the contrary Vice is opposed to virtue. Now faith is a virtue, and unbelief is opposed to it. Therefore unbelief is a sin.
I answer that Unbelief may be taken in two ways: first, by way of pure negation, so that a man be called an unbeliever, merely because he has not the faith. Secondly, unbelief may be taken by way of opposition to the faith; in which sense a man refuses to hear the faith, or despises it, according to Is 53,1: "Who hath believed our report?" It is this that completes the notion of unbelief, and it is in this sense that unbelief is a sin.If, however, we take it by way of pure negation, as we find it in those who have heard nothing about the faith, it bears the character, not of sin, but of punishment, because such like ignorance of Divine things is a result of the sin of our first parent. If such like unbelievers are damned, it is on account of other sins, which cannot be taken away without faith, but not on account of their sin of unbelief. Hence Our Lord said (Jn 15,22) "If I had not come, and spoken to them, they would not have sin"; which Augustine expounds (Tract. lxxxix in Joan.) as "referring to the sin whereby they believed not in Christ."
Reply to Objection: 1. To have the faith is not part of human nature, but it is part of human nature that man's mind should not thwart his inner instinct, and the outward preaching of the truth. Hence, in this way, unbelief is contrary to nature.
2. This argument takes unbelief as denoting a pure negation.
3. Unbelief, in so far as it is a sin, arises from pride, through which man is unwilling to subject his intellect to the rules of faith, and to the sound interpretation of the Fathers. Hence Gregory says (Moral. xxxi, 45) that "presumptuous innovations arise from vainglory."It might also be replied that just as the theological virtues are not reduced to the cardinal virtues, but precede them, so too, the vices opposed to the theological virtues are not reduced to the capital vices.
Objection: 1. It would seem that unbelief is not in the intellect as its subject. For every sin is in the will, according to Augustine (De Duabus Anim. x, xi). Now unbelief is a sin, as stated above (Article ). Therefore unbelief resides in the will and not in the intellect.
2. Further, unbelief is sinful through contempt of the preaching of the faith. But contempt pertains to the will. Therefore unbelief is in the will.
3. Further, a gloss [*Augustine, Enchiridion lx.] on 2Co 11,14 "Satan . . . transformeth himself into an angel of light," says that if "a wicked angel pretend to be a good angel, and be taken for a good angel, it is not a dangerous or an unhealthy error, if he does or says what is becoming to a good angel." This seems to be because of the rectitude of the will of the man who adheres to the angel, since his intention is to adhere to a good angel. Therefore the sin of unbelief seems to consist entirely in a perverse will: and, consequently, it does not reside in the intellect.
On the contrary Things which are contrary to one another are in the same subject. Now faith, to which unbelief is opposed, resides in the intellect. Therefore unbelief also is in the intellect.
I answer that As stated above (FS, Question , Articles ,2), sin is said to be in the power which is the principle of the sinful act. Now a sinful act may have two principles: one is its first and universal principle, which commands all acts of sin; and this is the will, because every sin is voluntary. The other principle of the sinful act is the proper and proximate principle which elicits the sinful act: thus the concupiscible is the principle of gluttony and lust, wherefore these sins are said to be in the concupiscible. Now dissent, which is the act proper to unbelief, is an act of the intellect, moved, however, by the will, just as assent is.Therefore unbelief, like faith, is in the intellect as its proximate subject. But it is in the will as its first moving principle, in which way every sin is said to be in the will.
Reply to Objection: 1. Hence the Reply to the First Objection is clear.
2. The will's contempt causes the intellect's dissent, which completes the notion of unbelief. Hence the cause of unbelief is in the will, while unbelief itself is in the intellect.
3. He that believes a wicked angel to be a good one, does not dissent from a matter of faith, because "his bodily senses are deceived, while his mind does not depart from a true and right judgment" as the gloss observes [*Augustine, Enchiridion lx]. But, according to the same authority, to adhere to Satan when he begins to invite one to his abode, i.e. wickedness and error, is not without sin.
Objection: 1. It would seem that unbelief is not the greatest of sins. For Augustine says (De Bapt. contra Donat. iv, 20): "I should hesitate to decide whether a very wicked Catholic ought to be preferred to a heretic, in whose life one finds nothing reprehensible beyond the fact that he is a heretic." But a heretic is an unbeliever. Therefore we ought not to say absolutely that unbelief is the greatest of sins.
2. Further, that which diminishes or excuses a sin is not, seemingly, the greatest of sins. Now unbelief excuses or diminishes sin: for the Apostle says (1Tm 1,12-13): "I . . . before was a blasphemer, and a persecutor and contumelious; but I obtained . . . mercy . . . because I did it ignorantly in unbelief." Therefore unbelief is not the greatest of sins.
3. Further, the greater sin deserves the greater punishment, according to Dt 25,2: "According to the measure of the sin shall the measure also of the stripes be." Now a greater punishment is due to believers than to unbelievers, according to He 10,29: "How much more, do you think, he deserveth worse punishments, who hath trodden under foot the Son of God, and hath esteemed the blood of the testament unclean, by which he was sanctified?" Therefore unbelief is not the greatest of sins.
On the contrary Augustine, commenting on Jn 15,22, "If I had not come, and spoken to them, they would not have sin," says (Tract. lxxxix in Joan.): "Under the general name, He refers to a singularly great sin. For this," viz. infidelity, "is the sin to which all others may be traced." Therefore unbelief is the greatest of sins.
I answer that Every sin consists formally in aversion from God, as stated above (FS, Question , Article ; FS, Question , Article ). Hence the more a sin severs man from God, the graver it is. Now man is more than ever separated from God by unbelief, because he has not even true knowledge of God: and by false knowledge of God, man does not approach Him, but is severed from Him.Nor is it possible for one who has a false opinion of God, to know Him in any way at all, because the object of his opinion is not God. Therefore it is clear that the sin of unbelief is greater than any sin that occurs in the perversion of morals. This does not apply to the sins that are opposed to the theological virtues, as we shall stated further on (Question , Article ; Question , Article , ad 2; Question , Article , ad 3).
Reply to Objection: 1. Nothing hinders a sin that is more grave in its genus from being less grave in respect of some circumstances. Hence Augustine hesitated to decide between a bad Catholic, and a heretic not sinning otherwise, because although the heretic's sin is more grave generically, it can be lessened by a circumstance, and conversely the sin of the Catholic can, by some circumstance, be aggravated.
2. Unbelief includes both ignorance, as an accessory thereto, and resistance to matters of faith, and in the latter respect it is a most grave sin. In respect, however, of this ignorance, it has a certain reason for excuse, especially when a man sins not from malice, as was the case with the Apostle.
3. An unbeliever is more severely punished for his sin of unbelief than another sinner is for any sin whatever, if we consider the kind of sin. But in the case of another sin, e.g. adultery, committed by a believer, and by an unbeliever, the believer, other things being equal, sins more gravely than the unbeliever, both on account of his knowledge of the truth through faith, and on account of the sacraments of faith with which he has been satiated, and which he insults by committing sin.
Objection: 1. It would seem that each act of an unbeliever is a sin. Because a gloss on Rm 14,23, "All that is not of faith is sin," says: "The whole life of unbelievers is a sin." Now the life of unbelievers consists of their actions. Therefore every action of an unbeliever is a sin.
2. Further, faith directs the intention. Now there can be no good save what comes from a right intention. Therefore, among unbelievers, no action can be good.
3. Further, when that which precedes is corrupted, that which follows is corrupted also. Now an act of faith precedes the acts of all the virtues. Therefore, since there is no act of faith in unbelievers, they can do no good work, but sin in every action of theirs.
On the contrary It is said of Cornelius, while yet an unbeliever (Ac 10,4 Ac 10,31), that his alms were acceptable to God. Therefore not every action of an unbeliever is a sin, but some of his actions are good.
I answer that As stated above (FS, Question , Articles ,4) mortal sin takes away sanctifying grace, but does not wholly corrupt the good of nature. Since therefore, unbelief is a mortal sin, unbelievers are without grace indeed, yet some good of nature remains in them. Consequently it is evident that unbelievers cannot do those good works which proceed from grace, viz. meritorious works; yet they can, to a certain extent, do those good works for which the good of nature suffices.Hence it does not follow that they sin in everything they do; but whenever they do anything out of their unbelief, then they sin. For even as one who has the faith, can commit an actual sin, venial or even mortal, which he does not refer to the end of faith, so too, an unbeliever can do a good deed in a matter which he does not refer to the end of his unbelief.
Reply to Objection: 1. The words quoted must be taken to mean either that the life of unbelievers cannot be sinless, since without faith no sin is taken away, or that whatever they do out of unbelief, is a sin. Hence the same authority adds: "Because every one that lives or acts according to his unbelief, sins grievously."
2. Faith directs the intention with regard to the supernatural last end: but even the light of natural reason can direct the intention in respect of a connatural good.
3. Unbelief does not so wholly destroy natural reason in unbelievers, but that some knowledge of the truth remains in them, whereby they are able to do deeds that are generically good. With regard, however, to Cornelius, it is to be observed that he was not an unbeliever, else his works would not have been acceptable to God, whom none can please without faith. Now he had implicit faith, as the truth of the Gospel was not yet made manifest: hence Peter was sent to him to give him fuller instruction in the faith.
Objection: 1. It would seem that there are not several species of unbelief. For, since faith and unbelief are contrary to one another, they must be about the same thing. Now the formal object of faith is the First Truth, whence it derives its unity, although its matter contains many points of belief. Therefore the object of unbelief also is the First Truth; while the things which an unbeliever disbelieves are the matter of his unbelief. Now the specific difference depends not on material but on formal principles. Therefore there are not several species of unbelief, according to the various points which the unbeliever disbelieves.
2. Further, it is possible to stray from the truth of faith in an infinite number of ways. If therefore the various species of unbelief correspond to the number of various errors, it would seem to follow that there is an infinite number of species of unbelief, and consequently, that we ought not to make these species the object of our consideration.
3. Further, the same thing does not belong to different species. Now a man may be an unbeliever through erring about different points of truth. Therefore diversity of errors does not make a diversity of species of unbelief: and so there are not several species of unbelief.
On the contrary Several species of vice are opposed to each virtue, because "good happens in one way, but evil in many ways," according to Dionysius (Div. Nom. iv) and the Philosopher (Ethic. ii, 6). Now faith is a virtue. Therefore several species of vice are opposed to it.
I answer that As stated above (FS, Question , Article ; FS, Question , Article ), every virtue consists in following some rule of human knowledge or operation. Now conformity to a rule happens one way in one matter, whereas a breach of the rule happens in many ways, so that many vices are opposed to one virtue. The diversity of the vices that are opposed to each virtue may be considered in two ways, first, with regard to their different relations to the virtue: and in this way there are determinate species of vices contrary to a virtue: thus to a moral virtue one vice is opposed by exceeding the virtue, and another, by falling short of the virtue. Secondly, the diversity of vices opposed to one virtue may be considered in respect of the corruption of the various conditions required for that virtue. In this way an infinite number of vices are opposed to one virtue, e.g. temperance or fortitude, according to the infinite number of ways in which the various circumstances of a virtue may be corrupted, so that the rectitude of virtue is forsaken. For this reason the Pythagoreans held evil to be infinite.Accordingly we must say that if unbelief be considered in comparison to faith, there are several species of unbelief, determinate in number. For, since the sin of unbelief consists in resisting the faith, this may happen in two ways: either the faith is resisted before it has been accepted, and such is the unbelief of pagans or heathens; or the Christian faith is resisted after it has been accepted, and this either in the figure, and such is the unbelief of the Jews, or in the very manifestation of truth, and such is the unbelief of heretics. Hence we may, in a general way, reckon these three as species of unbelief.If, however, the species of unbelief be distinguished according to the various errors that occur in matters of faith, there are not determinate species of unbelief: for errors can be multiplied indefinitely, as Augustine observes (De Haeresibus).
Reply to Objection: 1. The formal aspect of a sin can be considered in two ways. First, according to the intention of the sinner, in which case the thing to which the sinner turns is the formal object of his sin, and determines the various species of that sin. Secondly, it may be considered as an evil, and in this case the good which is forsaken is the formal object of the sin; which however does not derive its species from this point of view, in fact it is a privation. We must therefore reply that the object of unbelief is the First Truth considered as that which unbelief forsakes, but its formal aspect, considered as that to which unbelief turns, is the false opinion that it follows: and it is from this point of view that unbelief derives its various species. Hence, even as charity is one, because it adheres to the Sovereign Good, while there are various species of vice opposed to charity, which turn away from the Sovereign Good by turning to various temporal goods, and also in respect of various inordinate relations to God, so too, faith is one virtue through adhering to the one First Truth, yet there are many species of unbelief, because unbelievers follow many false opinions.
2. This argument considers the various species of unbelief according to various points in which errors occur.
3. Since faith is one because it believes in many things in relation to one, so may unbelief, although it errs in many things, be one in so far as all those things are related to one. Yet nothing hinders one man from erring in various species of unbelief, even as one man may be subject to various vices, and to various bodily diseases.
Summa Th. II-II EN Qu.9