Summa Theologica, by St. Thomas Aquinas, , at sacred-texts.com
We must now consider truth and the vices opposed thereto. Concerning truth there are four points of inquiry:
(1) Whether truth is a virtue?
(2) Whether it is a special virtue?
(3) Whether it is a part of justice?
(4) Whether it inclines to that which is less?
Objection 1: It seems that truth is not a virtue. For the first of virtues is faith, whose object is truth. Since then the object precedes the habit and the act, it seems that truth is not a virtue, but something prior to virtue.
Objection 2: Further, according to the Philosopher (Ethic. iv, 7), it belongs to truth that a man should state things concerning himself to be neither more nor less than they are. But this is not always praiseworthy---neither in good things, since according to Prov. 27:2, "Let another praise thee, and not thy own mouth"---nor even in evil things, because it is written in condemnation of certain people (Is. 3:9): "They have proclaimed abroad their sin as Sodom, and they have not hid it." Therefore truth is not a virtue.
Objection 3: Further, every virtue is either theological, or intellectual, or moral. Now truth is not a theological virtue, because its object is not God but temporal things. For Tully says (De Invent. Rhet. ii) that by "truth we faithfully represent things as they are were, or will be." Likewise it is not one of the intellectual virtues, but their end. Nor again is it a moral virtue, since it is not a mean between excess and deficiency, for the more one tells the truth, the better it is. Therefore truth is not a virtue.
On the contrary, The Philosopher both in the Second and in the Fourth Book of Ethics places truth among the other virtues.
I answer that, Truth can be taken in two ways. First, for that by reason of which a thing is said to be true, and thus truth is not a virtue, but the object or end of a virtue: because, taken in this way, truth is not a habit, which is the genus containing virtue, but a certain equality between the understanding or sign and the thing understood or signified, or again between a thing and its rule, as stated in the FP, Q, A; FP, Q, A. Secondly, truth may stand for that by which a person says what is true, in which sense one is said to be truthful. This truth or truthfulness must needs be a virtue, because to say what is true is a good act: and virtue is "that which makes its possessor good, and renders his action good."
Reply to Objection 1: This argument takes truth in the first sense.
Reply to Objection 2: To state that which concerns oneself, in so far as it is a statement of what is true, is good generically. Yet this does not suffice for it to be an act of virtue, since it is requisite for that purpose that it should also be clothed with the due circumstances, and if these be not observed, the act will be sinful. Accordingly it is sinful to praise oneself without due cause even for that which is true: and it is also sinful to publish one's sin, by praising oneself on that account, or in any way proclaiming it uselessly.
Reply to Objection 3: A person who says what is true, utters certain signs which are in conformity with things; and such signs are either words, or external actions, or any external thing. Now such kinds of things are the subject-matter of the moral virtues alone, for the latter are concerned with the use of the external members, in so far as this use is put into effect at the command of the will. Wherefore truth is neither a theological, nor an intellectual, but a moral virtue. And it is a mean between excess and deficiency in two ways. First, on the part of the object, secondly, on the part of the act. On the part of the object, because the true essentially denotes a kind of equality, and equal is a mean between more and less. Hence for the very reason that a man says what is true about himself, he observes the mean between one that says more than the truth about himself, and one that says less than the truth. On the part of the act, to observe the mean is to tell the truth, when one ought, and as one ought. Excess consists in making known one's own affairs out of season, and deficiency in hiding them when one ought to make them known.
Objection 1: It seems that truth is not a special virtue. For the true and the good are convertible. Now goodness is not a special virtue, in fact every virtue is goodness, because "it makes its possessor good." Therefore truth is not a special virtue.
Objection 2: Further, to make known what belongs to oneself is an act of truth as we understand it here. But this belongs to every virtue, since every virtuous habit is made known by its own act. Therefore truth is not a special virtue.
Objection 3: Further, the truth of life is the truth whereby one lives aright, and of which it is written (Is. 38:3): "I beseech Thee . . . remember how I have walked before Thee in truth, and with a perfect heart." Now one lives aright by any virtue, as follows from the definition of virtue given above (FS, Q, A). Therefore truth is not a special virtue.
Objection 4: Further, truth seems to be the same as simplicity, since hypocrisy is opposed to both. But simplicity is not a special virtue, since it rectifies the intention, and that is required in every virtue. Therefore neither is truth a special virtue.
On the contrary, It is numbered together with other virtues (Ethic. ii, 7).
I answer that, The nature of human virtue consists in making a man's deed good. Consequently whenever we find a special aspect of goodness in human acts, it is necessary that man be disposed thereto by a special virtue. And since according to Augustine (De Nat. Boni iii) good consists in order, it follows that a special aspect of good will be found where there is a special order. Now there is a special order whereby our externals, whether words or deeds, are duly ordered in relation to some thing, as sign to thing signified: and thereto man is perfected by the virtue of truth. Wherefore it is evident that truth is a special virtue.
Reply to Objection 1: The true and the good are convertible as to subject, since every true thing is good, and every good thing is true. But considered logically, they exceed one another, even as the intellect and will exceed one another. For the intellect understands the will and many things besides, and the will desires things pertaining to the intellect, and many others. Wherefore the "true" considered in its proper aspect as a perfection of the intellect is a particular good, since it is something appetible: and in like manner the "good" considered in its proper aspect as the end of the appetite is something true, since it is something intelligible. Therefore since virtue includes the aspect of goodness, it is possible for truth to be a special virtue, just as the "true" is a special good; yet it is not possible for goodness to be a special virtue, since rather, considered logically, it is the genus of virtue.
Reply to Objection 2: The habits of virtue and vice take their species from what is directly intended, and not from that which is accidental and beside the intention. Now that a man states that which concerns himself, belongs to the virtue of truth, as something directly intended: although it may belong to other virtues consequently and beside his principal intention. For the brave man intends to act bravely: and that he shows his fortitude by acting bravely is a consequence beside his principal intention.
Reply to Objection 3: The truth of life is the truth whereby a thing is true, not whereby a person says what is true. Life like anything else is said to be true, from the fact that it attains its rule and measure, namely, the divine law; since rectitude of life depends on conformity to that law. This truth or rectitude is common to every virtue.
Reply to Objection 4: Simplicity is so called from its opposition to duplicity, whereby, to wit, a man shows one thing outwardly while having another in his heart: so that simplicity pertains to this virtue. And it rectifies the intention, not indeed directly (since this belongs to every virtue), but by excluding duplicity, whereby a man pretends one thing and intends another.
Objection 1: It seems that truth is not a part of justice. For it seems proper to justice to give another man his due. But, by telling the truth, one does not seem to give another man his due, as is the case in all the foregoing parts of justice. Therefore truth is not a part of justice.
Objection 2: Further, truth pertains to the intellect: whereas justice is in the will, as stated above (Q, A). Therefore truth is not a part of justice.
Objection 3: Further, according to Jerome truth is threefold, namely, "truth of life," "truth of justice," and "truth of doctrine." But none of these is a part of justice. For truth of life comprises all virtues, as stated above (A, ad 3): truth of justice is the same as justice, so that it is not one of its parts; and truth of doctrine belongs rather to the intellectual virtues. Therefore truth is nowise a part of justice.
On the contrary, Tully (De Invent. Rhet. ii) reckons truth among the parts of justice.
I answer that, As stated above (Q), a virtue is annexed to justice, as secondary to a principal virtue, through having something in common with justice, while falling short from the perfect virtue thereof. Now the virtue of truth has two things in common with justice. In the first place it is directed to another, since the manifestation, which we have stated to be an act of truth, is directed to another, inasmuch as one person manifests to another the things that concern himself. In the second place, justice sets up a certain equality between things, and this the virtue of truth does also, for it equals signs to the things which concern man himself. Nevertheless it falls short of the proper aspect of justice, as to the notion of debt: for this virtue does not regard legal debt, which justice considers, but rather the moral debt, in so far as, out of equity, one man owes another a manifestation of the truth. Therefore truth is a part of justice, being annexed thereto as a secondary virtue to its principal.
Reply to Objection 1: Since man is a social animal, one man naturally owes another whatever is necessary for the preservation of human society. Now it would be impossible for men to live together, unless they believed one another, as declaring the truth one to another. Hence the virtue of truth does, in a manner, regard something as being due.
Reply to Objection 2: Truth, as known, belongs to the intellect. But man, by his own will, whereby he uses both habits and members, utters external signs in order to manifest the truth, and in this way the manifestation of the truth is an act of the will.
Reply to Objection 3: The truth of which we are speaking now differs from the truth of life, as stated in the preceding A, ad 3.
We speak of the truth of justice in two ways. In one way we refer to the fact that justice itself is a certain rectitude regulated according to the rule of the divine law; and in this way the truth of justice differs from the truth of life, because by the truth of life a man lives aright in himself, whereas by the truth of justice a man observes the rectitude of the law in those judgments which refer to another man: and in this sense the truth of justice has nothing to do with the truth of which we speak now, as neither has the truth of life. In another way the truth of justice may be understood as referring to the fact that, out of justice, a man manifests the truth, as for instance when a man confesses the truth, or gives true evidence in a court of justice. This truth is a particular act of justice, and does not pertain directly to this truth of which we are now speaking, because, to wit, in this manifestation of the truth a man's chief intention is to give another man his due. Hence the Philosopher says (Ethic. iv, 7) in describing this virtue: "We are not speaking of one who is truthful in his agreements, nor does this apply to matters in which justice or injustice is questioned."
The truth of doctrine consists in a certain manifestation of truths relating to science wherefore neither does this truth directly pertain to this virtue, but only that truth whereby a man, both in life and in speech, shows himself to be such as he is, and the things that concern him, not other, and neither greater nor less, than they are. Nevertheless since truths of science, as known by us, are something concerning us, and pertain to this virtue, in this sense the truth of doctrine may pertain to this virtue, as well as any other kind of truth whereby a man manifests, by word or deed, what he knows.
Objection 1: It seems that the virtue of truth does not incline to that which is less. For as one incurs falsehood by saying more, so does one by saying less: thus it is no more false that four are five, than that four are three. But "every falsehood is in itself evil, and to be avoided," as the Philosopher declares (Ethic. iv, 7). Therefore the virtue of truth does not incline to that which is less rather than to that which is greater.
Objection 2: Further, that a virtue inclines to the one extreme rather than to the other, is owing to the fact that the virtue's mean is nearer to the one extreme than to the other: thus fortitude is nearer to daring than to timidity. But the mean of truth is not nearer to one extreme than to the other; because truth, since it is a kind of equality, holds to the exact mean. Therefore truth does not more incline to that which is less.
Objection 3: Further, to forsake the truth for that which is less seems to amount to a denial of the truth, since this is to subtract therefrom; and to forsake the truth for that which is greater seems to amount to an addition thereto. Now to deny the truth is more repugnant to truth than to add something to it, because truth is incompatible with the denial of truth, whereas it is compatible with addition. Therefore it seems that truth should incline to that which is greater rather than to that which is less.
On the contrary, The Philosopher says (Ethic. iv, 7) that "by this virtue a man declines rather from the truth towards that which is less."
I answer that, There are two ways of declining from the truth to that which is less. First, by affirming, as when a man does not show the whole good that is in him, for instance science, holiness and so forth. This is done without prejudice to truth, since the lesser is contained in the greater: and in this way this virtue inclines to what is less. For, as the Philosopher says (Ethic. iv, 7), "this seems to be more prudent because exaggerations give annoyance." For those who represent themselves as being greater than they are, are a source of annoyance to others, since they seem to wish to surpass others: whereas those who make less account of themselves are a source of pleasure, since they seem to defer to others by their moderation. Hence the Apostle says (2 Cor. 12:6): "Though I should have a mind to glory, I shall not be foolish: for I will say the truth. But I forbear, lest any man should think of me above that which he seeth in me or anything he heareth from me."
Secondly, one may incline to what is less by denying, so as to say that what is in us is not. In this way it does not belong to this virtue to incline to what is less, because this would imply falsehood. And yet this would be less repugnant to the truth, not indeed as regards the proper aspect of truth, but as regards the aspect of prudence, which should be safeguarded in all the virtues. For since it is fraught with greater danger and is more annoying to others, it is more repugnant to prudence to think or boast that one has what one has not, than to think or say that one has not what one has.
This suffices for the Replies to the Objections.