Incontemporary debates in Catholic moral theology, a distinction is often drawnbetween actions that are flatly ruled out in principle and those whosepermissibility or impermissibility is a matter of prudential judgment.  For example, it is often noted that abortionis wrong always and in principle, whereas how many immigrants a country oughtto allow in and under what conditions are matters of prudential judgment.  But exactly what does this mean, and how dowe tell the difference between the cases?

It isimportant at the outset to put aside some common misunderstandings.  The difference between matters of principleand matters of prudential judgment is nota difference between moral questions and merely pragmatic ones.  Morality is at issue in both cases.  Prudence is,after all, one of the cardinal moral virtues. One can be mistaken in one’s prudential judgments, and when one is, oneis guilty of imprudence, which is a kind of moral failure (whether or not oneis culpable for the failure).

Contrary toanother misunderstanding (which I recently had occasionto rebut), to say that something is a matter of prudential judgmentand then go on to note that reasonable people can differ in their prudentialjudgments is not to commit oneself toany kind of moral relativism.  Prudentialjudgments can indeed simply be mistaken. To say that reasonable people can disagree is merely to note that aperson might have made such a judgment in good faith on the basis of theevidence available to him, even if the evidence later turns out to bemisleading or his reasoning turns out to have been flawed.  He is still objectively wrong all the same.  Or there may in some cases be more than onereasonable way to apply a certain objective and universal moral principle, sothat reasonable people might opt to apply it in any of these different ways.

As always,illumination can be found in St. Thomas Aquinas.  In several places, he makes remarks that arerelevant to understanding the difference between straightforward matters ofprinciple and matters of prudential judgment. For example, in On Evil,Aquinas notes:

The will of a rational creature is obliged to be subject toGod, but this is achieved by affirmative and negative precepts, of which thenegative precepts oblige always and on all occasions, and the affirmativeprecepts oblige always but not on every occasion… One sins mortally whodishonors God by transgressing a negative precept or not fulfilling an affirmativeprecept on an occasion when it obliges. (Question VI, Regan translation)

Though thedistinction between matters of principle and matters of prudence is somewhatloose, it seems largely (though perhaps not always) to correspond to Aquinas’sdistinction between negative precepts, which oblige on every occasion, andaffirmative precepts, which do not.  Whatthis distinction amounts to is madeclearer in some remarks St. Thomas makes when commenting on St. Paul’s Epistleto the Romans:

He lists the negative precepts, which forbid a person to doevil to his neighbor.  And this for tworeasons.  First, because the negativeprecepts are more universal both as to time and as to persons.  As to time, because the negative preceptsoblige always and at every moment.  Forthere is no time when one may steal or commit adultery.  Affirmative precepts, on the other hand,oblige always but not at every moment, but at certain times and places: for aman is not obliged to honor his parents every minute of the day, but at certaintimes and places.  Negative precepts aremore universal as to persons, because no man may be harmed.  Second, because they are more obviouslyobserved by love of neighbor than are the affirmative.  For a person who loves another, ratherrefrains from harming him than gives him benefits, which he is sometimes unableto give. (Commentary on the Letter ofSaint Paul to the Romans, Chapter 13, Lecture2)

Aquinas’sexamples hopefully make his meaning clear. Consider the negative precept “Do not commit adultery.”  Because adultery is intrinsically evil, wemust never commit it, period, regardless of the circumstances.  And because we therefore needn’t considercircumstances, no judgment of prudence is required in order to apply the precept to circumstances.  Whatever the circumstances happen to be, wesimply refrain from committing adultery, and that’s that.

By contrast,applying the affirmative precept “Honor your father and mother” does requireattention to circumstances.  To be sure,the precept never fails to be binding on us (which is what Aquinas means bysaying that it “obliges always”) but exactlywhat obeying it amounts to depends crucially on circumstances (which is whyhe says that “times and places” are relevant). For example, suppose your father commands you to bring him a bottle ofwine.  Does honoring him oblige you to doso?  It depends.  Suppose he has had a hard day, finds itrelaxing to drink in moderation, and is infirm and has trouble walking.  Then it would certainly dishonor your fatherto ignore him and make him get up and fetch the bottle himself.  But suppose instead that he has a seriousdrinking problem, has already had too much wine, and will likely beat you oryour mother if he gets any drunker.  Thenit would not dishonor him to refuseto bring the bottle.

As Aquinassuggests in the Romans commentary, affirmative precepts involve providingsomeone with a benefit of some kind, which one is “sometimes unable togive.”  Consider the affirmative preceptto give alms.  Even more obviously thanin the case of the precept to honor one’s parents, what following this preceptentails concretely is highly dependent on circumstances.  Obviously one cannot always be giving alms,for even if one tried to do so, one would quickly run out of money and not onlybe unable to give any further alms, but would be in need of alms oneself.  How to follow this affirmative preceptclearly requires making a judgment of prudence. How much money do I need for my own family?  How much might I be able to spare for others,and how frequently?  Exactly who, amongall the people who need alms, should I give to? Should I give by donating money, or instead by giving food and thelike?  The answers to these questions arehighly dependent on circumstances and will vary from person to person, place toplace, and time to time.

The morecomplicated and variable the circumstances, the more difficult it can be todecide on a single correct answer and thus the greater the scope for reasonabledisagreement.  The disagreement can bereasonable in either of two ways.  First,what might be obligatory for one person given the details of his circumstancesmay not be obligatory for another person given the details of his own verydifferent circumstances.  For example, arich man is bound to be obligated to give more in the way of alms than a poorman is.  Second, disagreement can bereasonable insofar as the complexity of the situation might make it uncertainwhich course of action is best even for people in the same personal circumstances.  Aquinas makes such points in the Summa Theologiae:

The practical reason… is busied with contingent matters,about which human actions are concerned: and consequently, although there isnecessity in the general principles, the more we descend to matters of detail,the more frequently we encounter defects. Accordingly then… in matters of action, truth or practical rectitude isnot the same for all, as to matters of detail, but only as to the generalprinciples: and where there is the same rectitude in matters of detail, it isnot equally known to all.

It is therefore evident that… as to the proper conclusions ofthe practical reason, neither is the truth or rectitude the same for all, nor,where it is the same, is it equally known by all.  Thus it is right and true for all to actaccording to reason: and from this principle it follows as a proper conclusion,that goods entrusted to another should be restored to their owner.  Now this is true for the majority of cases:but it may happen in a particular case that it would be injurious, andtherefore unreasonable, to restore goods held in trust; for instance, if theyare claimed for the purpose of fighting against one's country.  And this principle will be found to fail themore, according as we descend further into detail, e.g. if one were to say thatgoods held in trust should be restored with such and such a guarantee, or insuch and such a way; because the greater the number of conditions added, thegreater the number of ways in which the principle may fail, so that it be notright to restore or not to restore.  (Summa Theologiae I-II.94.4)

Points likethese are ignored when, for example, it is alleged that Catholics who favorenforcing immigration laws are somehow no less at odds with the Church’steaching than Catholics who favor legalized abortion.  For one thing, as I’ve shown elsewhere,the Church herself acknowledges the legitimacy of restrictions onimmigration.  For another, the principlesinvolved in the two cases are crucially different in exactly the ways Aquinasdescribes.  “Do not murder” is a negativeprecept that flatly rules out a certain kind of action, regardless of thecircumstances.  And since abortion is akind of murder, it flatly rules out abortion regardless of thecircumstances.  There is no question ofprudential judgment here.

By contrast,“Welcome the stranger” is an affirmative precept, whose application is highlydependent on circumstances.  Moreover,these circumstances involve millions of people, and complex matters of culture,law, economics, and national security.  Here,even more than in the case of almsgiving, there is much room for reasonabledisagreement about how best to apply the precept.  That would be obvious even if the Church hadnot explicitly acknowledged that immigration can be restricted for variousreasons (as, again, in fact she has).

It is thussheer sophistry to pretend that by appealing to the notion of prudentialjudgment, Catholics who support immigration restrictions are somehow trying torationalize dissent from Catholic teaching. On the contrary, they are (whether one agrees with them or not) fullywithin the bounds of what Catholic moral theology has always acknowledged to bea legitimate range of opinion among Catholics.

Similarsophistry is committed by those who speak as if supporting a living wage orgovernment provision of health care ought to be no less a matter of “pro-life”concern than abortion and euthanasia. Here too the comparison is specious. Abortion and euthanasia are flatly prohibited in all circumstancesbecause they violate the negative precept “Do not murder.”  But principles like “Pay a living wage” or“Ensure health care for all” are affirmative precepts, and how best to apply themto concrete circumstances is highly dependent on various complex and contingenteconomic considerations.  There can be noreasonable disagreement among Catholics about whether abortion and euthanasiashould be illegal.  But there can bereasonable disagreement among them about whether a certain specific minimumwage law is a good idea, or which sort of economic arrangements provide thebest way to secure health coverage for all. 

The samepoint can be made about other contemporary controversies, mutatis mutandis.  And itapplies across the political spectrum (e.g. to those who, during the most recentpresidential election, pretended that there could be no reasonable doubt that anyloyal Catholic must vote for theirfavored candidate).