b. About the Second Doubt

22. As to the second doubt [n.13] I say that he to whom one swears either accepts (from positive law or common custom) that the oath is as it were simply assertive of what is sworn, or that it is not as it were simply assertive but induces to probable belief of the thing sworn.

23. In the first way I say that one who swears something that is in any way doubtful (that is, something not simply certain and true and deliberate) sins mortally, because he is bringing in God as witness to confirm that what he asserts is simply certain and true when it is not simply certain.

24. And in this way must be understood all oaths of those who swear in court, where the sort of sentence accustomed to be passed there should not be passed unless what is asserted is simply certain. For example, a sentence of death should not be passed save for a crime that is certain. Therefore, he who swears that the accused is guilty of the crime when he is not certain, however much he may nevertheless conjecture that the accused is guilty and swears this in such a forum (where, by positive law or custom, a condemnation to death follows), he sins mortally. The like holds of any forum where (from the fact someone is convicted through sworn oaths) the accused is condemned as simply guilty or as infamous with the infamy of law. For in this case not only is irreverence done to the name of God against the commandment of the first table, but there is a pernicious lie because harmful to one’s neighbor [cf. d.38 n.23].

25. And if you say ‘it is useful for the republic; otherwise evil people will be too much multiplied’, God replies “You will execute what is just justly” [Deuteronomy 16.20]. For there are certain evils that are not to be punished by men but are to be left to divine vengeance - for instance all things where man, as man, cannot even sufficiently teach the truth in the way it ought to be taught for the purpose of justly passing a due sentence of punishment. Nor are the witnesses alone guilty in these cases but the judge too. And if a judge knows that by custom witnesses only swear under oath what they believe, then he should not pass such sentence as should be passed if guilt were simply proved before him. For he knows from custom that guilt is not proved before him sufficiently for the infliction of such a punishment.

26. But if by positive law or custom it is held that a sworn witness is not bound to depose what he is certain of but only what he believes, then the swearer does not sin, provided he make conjecture for this side rather than another from probable signs. The point is contained in Gregory IX Decretals I tit. 12, about making examination for holdy orders, where Pope Innocent replies, “as far as human fragility allows us to know, [the Church] both knows and testifies that this man is worthy of the burden of this sort of office.” Hence Pope Innocent says that

“in making such response we do not believe that anyone sins, provided he not speak against his conscience; for he does not assert simply that the candidate is worthy but asserts it as far as human fragility allows one to know, since one should judge him worthy whom one does not know to be unworthy.”

27. Therefore, in such promotions either to any dignity of office by election or to holy orders, or also in other colleges (as to mastership in universities, to prelacy in religions, or to other acts of the sort), if there is an approved custom that the responses of the respondents (under proffered oath, or under pledge of faith, or under promised obedience) should be understood only of belief ‘as far as human fragility permits us to know’, and that the presider does not know of any indignity in the candidate, then all such responses should be understood according to the common custom and the respondents do not sin in anything (though it would be safer to speak there with some qualification, as in the aforesaid Decretal, that one speaks not simply but as far as human fragility allows). And in such cases a judge who promotes such a candidate does not sin, because the custom is that giving such testimony of one’s belief is enough.

28. Here then ‘favor is enlarged and hatred is restricted’ according to the maxim of the law [Boniface VIII Decretals 6.V tit.12], because in matters of hate a sworn witness should speak the truth strictly, and a truth that is certain, for otherwise it is not a reason that the sentence of condemnation afterwards passed should be passed. In favorable matters it is sufficient for the person sworn to say what he believes to be true, above all where the custom or positive law in the college is of the sort that one speak one’s belief. For because of the truth as to belief thus testified, the presider can promote the candidate to such and such a rank.

29. Now universally, whether in favorable or hateful things, he who swears something the opposite of which he more believes than anything else, swearing even to that about which he is simply doubtful and where he does not assent in his heart more to one side than the other - such a person sins mortally in swearing, because he brings in God as witness for something he is in no way certain about which he ought to be certain about.