Arguments From Natural Reason: Plausible or Conclusive?

A Bleg

All right, all you faithful Catholics out there.

I’m about to make a “bleg”; that is, I’m going to beg something of the readers of this blog. I’m going to ask you to spell out, as best you can, in defense of the Catholic faith, the specific arguments from natural reason against a particular type/use of artificial birth control.

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What Prompted The Bleg

Russell Shaw’s article “The Elephant in the Living Room” muses about the widespread disobedience of Catholic couples to the Church’s teaching on contraception. It’s a good article, and there are some thoughtful comments from the readers, too.

One sentence jumped out at me, however:

I support the teaching on two grounds: first, the firm and constant teaching of the Magisterium over many centuries; second, the powerful and sophisticated rational argument against contraception developed by Germain Grisez and his colleagues in the “New Natural Law Theory” school.

There are two reasons presented here in defense of the Church’s teaching: (1.) That it is the consistent teaching of the Magisterium over the centuries; and, (2.) That there is a powerful and sophisticated rational argument against contraception.

Magisterial Consistency

That the Magisterium has taught against contraception consistently and firmly over many centuries seems accurate to me.

I have seen argument to the contrary, from a man who frequently comments here and elsewhere in the Catholic blogosphere.

If I remember the gist of his argument, it leans on (a.) the arguments made against contraception in earlier centuries relying on reasoning or on an understanding of biology which we no longer hold true; and (b.) an assertion that infallibility does not “spread like kudzu” through anything a churchman says, but is confined to particular vehicles (e.g. formal dogmatic definitions); and while the teaching can be found somewhere pretty consistently over time, it cannot be found in those particular vehicles with the consistency or forcefulness required to assert infallibility.

He thus holds that while it is true to claim that the teaching against artificial contraception is the opinion, on a matter of moral theology, of many recent popes and bishops, it lacks the unaltered history which would give it infallibility by the normal route, and the delivery and unambiguous phrasing which would give it infallibility by the extraordinary route.

I think I’m not yet qualified to respond to that argument comprehensively: My four years’ study prior to entering the Church notwithstanding, I am a neophyte. I still find the criteria for infallibility a bit doubt-inducing “at the edges.” (Also I may be misremembering his arguments or leaving bits out. If so, I suspect he’ll pop in to correct me, which I welcome.)

Still, arguments can be proven strong or weak by trying them out to see how they fare, so  I’ll attempt a neophyte’s response to (a.) and (b.) anyway:

(a.) I suppose that the arguments made against contraception in earlier centuries were an attempt to explain an existing tradition received from the apostles, rather than a development of doctrine. Thus the failure of a particular explanation does not defeat the doctrine, as if the doctrine had only originated as the conclusion of a particular argument, but merely leaves the doctrine in need of a better defense.

(b.) We have to avoid an either/or fallacy; e.g. “Either a teaching is found in a Papal Encyclical, preceded by the words ‘I dogmatically define and declare,’ or it isn’t authoritative and is merely some churchman’s private opinion which we may take or leave.” That is an exaggeration of the frequent commenter’s argument, mind you…but I think that his argument, while not so overtly fallacious, nevertheless neglects the ordinary Magisterial authority of the church which, while it may not contain the words “I dogmatically define and declare,” nevertheless carries an obligation of obedience under normal circumstances.

For this reason, when responding to him some months back, I said that even were I not persuaded that the Church’s teaching on contraception was infallible, I would still think (given the unambiguous phrasing of Humanae Vitae, et cetera) that the practice of NFP over and against contraception was obligatory at least as a discipline until the teaching was unambiguously changed. (Indeed, it would not seem too unreasonable were a teaching of that kind imposed solely on the post-Christian West as a penance and corrective for the “pornification” of our public square, even if it were not imposed elsewhere!)

“Powerful and Sophisticated Rational Argument”

So, until other argument worthy of consideration emerges, the question of infallibility and the history of Magisterial teaching is either settled, or a moot point, in my mind at least.

But what about the second assertion given in Shaw’s article, regarding arguments purely from natural reasoning?

Russell Shaw claims that there are sound natural-reasoning arguments confirming the Church’s teaching that it is not morally permissible to use non-abortifacient methods of artificial birth control, either to achieve a morally licit spacing of children, or for disease prevention, in an otherwise morally licit sexual act.

Fair enough. What are these natural-reasoning arguments, and are they only plausible, or are they conclusive?

Plausible Vs. Conclusive

For it’s one thing to hear an argument which, when evaluated, makes you say, “Well, okay, that sounds like it might be right. If I were already disposed to believe its conclusions anyway, then hearing that argument would slightly reinforce that belief.” That’s a plausible argument.

But it’s another thing entirely to hear an argument which, when evaluated, makes you say, “That settles it. I see no rational way out of the conclusions reached by that argument. All the doors are locked and all the windows barred; the holes are all stopped up and the fox faces the hounds; there is no escape save through willful ignorance and intellectual dishonesty.” That’s a conclusive argument.

It is not true that real-word arguments are never conclusive in this way. They sometimes are. Most often, they become conclusive by reductio ad absurdum; that is, by showing that all alternatives to their conclusions are self-contradictory. Two excellent Catholic refutations of the protestant doctrine of Sola Scriptura are of this kind.

Narrow Focus

The attentive reader will notice that I am asking only about the arguments which prohibit a particular kind of artificial contraception (the non-abortifacient kind), and that I am only interested in the prohibition of its use for otherwise morally licit purposes (prudent spacing of children, prevention of disease) in otherwise morally licit sexual acts (between married couples).

I take it as a given that the natural argument (that is, purely from human reasoning and requiring no recourse to special revelation) against abortion is sound. Peter Kreeft, at his website, has an audio download called Pro-Life Philosophy if anyone has any doubts on that topic. (Not to mention a lot of other great audio downloads!)

Since the argument against abortion is sound, so too is the argument against abortifacient methods of artificial birth control. These are not morally permissible.

Similarly the Scriptural mandates regarding marriage, the marriage debt, having a full “quiver,”  “go forth, be fruitful and multiply,” and so on prohibit us from holding the view that children are not a priceless blessing to be sought in marriage. I therefore exclude from the outset the moral permissibility of an intentionally sterile married life, the better to take many expensive vacations together.

My Motive: “Always Stand Ready To Defend…

I am not, in asking about this, looking for an excuse to weasel out of the Church’s teaching. (See my earlier comments regarding accepting the teaching even as a discipline.)

I would like to find that the argument against barrier (or other non-abortifacient) methods of artificial contraception was truly, firmly persuasive: Compulsory for the unbiased intellect.

(Yes, I’m aware there aren’t many people out there willing to have their minds changed by truthful argument. I suspect rather more people are willing to have their minds swayed by propaganda and fallacy, provided the swaying shoves them in a comfortable direction. All the same, we should be armed with the best (truthful!) arguments available. We should win not by deceit, but by knowing the subject so exhaustively that we know the counterarguments against our own view better than those who wield them. We should “stand ready to defend the hope” and to live and die for the truth…not least because we know Who the Truth Is.)

What I Have, And What I Lack

Anyway, I myself can think of several arguments in favor of the Church’s prohibition of the above-referenced contraceptive acts. Of these arguments,

  • Some are applicable to the particular type of contraceptive acts referenced above, but others aren’t;
  • Some argue purely from natural reasoning, but others require appeal to special revelation and even to specific views of sacramental theology; and,
  • Some are conclusive, but others are merely plausible-sounding.

So far so good. The problem is that I do not yet have, in my arsenal, an argument which is:

  • Applicable to the particular type of contraceptive act referenced above;
  • Purely argued from natural reasoning; and,
  • Entirely conclusive (to me, at least)

…and that’s disappointing. I have several arguments, but they all fail one of those three tests.

It is for that reason I am making this “bleg”:

What are the best natural-reason arguments against the type of contraceptive use specified above?

And are they, in your view (for mine may differ) merely plausible, or conclusive?

Present them as best you can, please (or provide a link to an excellent presentation, if you know of one).


  • Cord Hamrick

    Cord Hamrick is a husband and father of three, raised an evangelical Christian in Southern Baptist churches. After years of lurking, questioning, and eventually opining in the Catholic blogosphere, he was received into the Catholic Church at Easter Vigil, 2010. Cord is a sometime church musician, former praise-and-worship bandleader, frequent songwriter and arranger, occasional guitar teacher, and — because one really must somehow pay the bills — a developer of web-based software applications. He lives in the suburbs of Atlanta, Georgia, with his wife and three kids.

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