To find the moral truth and guide one’s choice, it is not enough to know moral principles and norms. Everything relevant, whether actual or possible, also must be taken into account, even though it is not normative. For these are facts one faces and cannot ignore, since they help constitute the possibilities available for choice while also limiting them. Not knowing enough about some fact relevant to a moral judgment and not at once succeeding in getting the necessary information, one should engage in further investigation.
Doubts of fact need not be resolved if the facts will not change one’s moral responsibilities. An important kind of case in which a doubt of fact is morally irrelevant occurs when someone chooses to do something immoral under a condition that might or might not obtain. Whether it does or does not, the person’s moral responsibility is the same: a sin already has been committed. For example, if someone decides to commit adultery if an attractive opportunity arises, he or she already has committed it. If someone decides to lie under oath only if it is absolutely necessary, he or she already has committed perjury.
When it is necessary to try to resolve a doubt of fact, the investigation should be shaped by two assumptions.
First, realizing that one is in doubt, a person may not simply presume that the “fact” in question is a fact. It must be proved or disproved before the doubt can be dismissed. For instance, if uncertain whether a debt was paid, one may not simply assume it was.
Second, if an act certainly has been done but one doubts whether it was done properly, one should begin by assuming it was, not allow a mere doubt to upset a settled situation. For example, if there is doubt about the validity of some legal act which certainly was done, validity is presumed while nullity must be proved.29
In attempting to settle doubts of fact, the methods depend on the subject matter. Moral theology cannot teach these methods, since they belong to other disciplines.
When in doubt about a matter of fact, a person often will find it necessary and useful to obtain others’ help. This will include trying to make sure the others are sufficiently familiar with the matter at hand and diligent in attending to the relevant facts. Also, because people’s presuppositions affect their beliefs about matters of fact, the preferred helper in investigating matters of fact relevant to a moral judgment should be someone who shares one’s Christian commitment.
Doubts about the existence and applicability of norms of positive law are a special case of doubts about facts, since from the moral point of view the existence and applicability of legal norms simply are facts. The relevant moral norm is that just norms of positive law ought to be obeyed (see 11.D.1). This norm is defeasible when norms of positive law are inapplicable (see 11.D.2).30
How far must people go in trying to settle doubts about facts? Plainly, if concerned with grave matter, possible mortal sin, or a major choice such as a vocational commitment, their inquiry should be pushed much further than it otherwise would be. Still, there is no general answer to this question, since it requires bringing prudence to bear on actual situations. Those who recognize their own limits can look for guidance to the example of mature, holy persons.
29. Note that this second presumption bears on acts and their moral, social, and legal meanings, not on products. If an automobile has been built and its builders doubt whether they bolted the steering mechanism together properly, they should check, not assume they did the job right. On these presumptions, see I. Aertnys, C. Damen, and I. Visser, C.Ss.R., Theologia moralis, ed. 18, 4 vols. (Turin: Marietti, 1967–69), 1:224–25; note that the third prudential principle they propose does not shape inquiry but directs judgment if inquiry fails to settle the doubt.
30. Epikeia as St. Thomas understands it (see S.t., 2–2, q. 120) is concerned precisely with the defeasibility of this norm. Thus, although epikeia is concerned exclusively with positive law, the way one rightly judges that a positive law should not be obeyed is similar to the way one finds true exceptions to other defeasible norms. How this is done was discussed in D, above.