Marriage and mortal sin

Brandon digs out a fantastic text from STA’s commentary on Corinthians:

…that the conjugal act is sometimes meritorious and without any mortal or venial sin, as when it is directed to the good of procreation and education of a child for the worship of God; for then it is an act of religion; or when it is performed for the sake of rendering the debt, it is an act of justice. But every virtuous act is meritorious, if it is performed with charity. But sometimes it is accompanied with venial sin, namely, when one is excited to the matrimonial act by concupiscence, which nevertheless stays within the limits of the marriage, namely, that he is content with his wife only. But sometimes it is performed with mortal sin, as when…

So guess: what is he going to say? Is sexual activity a mortal sin when “it is not open to procreation” (an answer that is at hand from what he says at the head of the quotation) or when “it is performed in an unnatural way”? Don’t we expect St. Thomas to mention some obvious perversion? Yet, in the casual way that he says all his revolutionary things, he says that sexual activity is a mortal sin when…

…the husband approaches the wife with the idea that he would just as gladly or more gladly approach another woman.


  1. Alan Aversa said,

    May 23, 2012 at 12:42 pm

    Typical St. Thomas getting to the crux of the issue 🙂

    • May 23, 2012 at 1:50 pm

      right – one could write a whole theory of sexuality from what STA is saying here. He recognizes the essential procreative nature of sex, but places it necessarily in the context of a relation that is uniquely personal. Procreation, taken by itself, could relate to any other fertile person just as much as ones own mate (another mate, for that matter, might serve the purpose better) – and therefore to limit sexual activity to this essential aspect would be a perversion. This is the best synthesis of the “two ends” of sexuality that I’ve ever read (though our speaking of “two ends” is a still a clunky way of putting it).

      Again there is an implicit personalism here (in the good sense of personalism, i.e. recognizing the moral significance of the person as a person).

      It’s also the best short explanation for the evil of pornography, since to watch it requires desiring your partner only as one among many.

      • Alan Aversa said,

        May 23, 2012 at 8:23 pm

        It’s like how a 1st grade teacher explains the 6th Commandment to prepare the children for First Communion: “Husbands and wives must be faithful to one another.”

        Sometimes the simplest explanations are the best.

  2. thenyssan said,

    May 23, 2012 at 4:13 pm

    This same line of argument can be found in ST Supp Q49 and therefore I assume in his commentary on the sentences. It’s a great argument, but I and my students always dwell on the middle (the venial sin part). I’m still not sure I have caught the sense Thomas is going for here.

    I don’t know that I’ve ever fully committed to an explanation on this point, but my students usually take it to mean that a sexual act for the purpose of sexual enjoyment or relief (“excited by concupiscence’) is a venial sin. In that sense it’s a lesser form of the indiscriminate sexual act that is mortally sinful.

    I’d be curious to hear your thoughts on that middle part.

    • May 23, 2012 at 9:13 pm

      I thought about it all afternoon, and this is the best answer I could come up with:

      First: what exactly is the opposite of concupiscence in this context? Are we to read St. Thomas as advocating sexual apathy? Or is it that he is advocating a rational, business-like sexuality where we close our eyes and rationally consider the good of the human race? And if it’s not apathy or calculated attention to the good of England, what is it?

      Though I haven’t made a thorough study of concupiscence in STA, I do know that it is a sort of love that is peculiar to sense appetite, but sense goods as sensed are peculiar to a subject as opposed to being common. But the very intensity of sexual desire is from the contact it has with the common good – we really do touch something of the divine (De Anima, 2:4). To enjoy this purely out of concupiscence is to cheat the good we touch and to act against its nature, since we want to enjoy common goods as mere particular goods. If this is right, then there is a certain mercy in saying it is only a venial sin! Shouldn’t we have a harsher judgment on someone who want to appropriate common goods to his own peculiar good?

  3. lee faber said,

    May 23, 2012 at 9:05 pm

    So what does this actually mean? To be mortal sin, would one have to form the intention that one would have sex with any woman who hapened to be there and consent to it, or is simply being ‘horny’ as they say, enough? It seems like a fine line.

    • Alan Aversa said,

      May 23, 2012 at 9:32 pm

      Read St. Alphonso di Liguori’s Theologia Moralis if you want all the gory details.

      Fr. Chad Ripperger, FSSP, summarizes St. Alphonso in this excellent talk on chastity from his Omaha marriage conference.

      • Alan Aversa said,

        May 23, 2012 at 9:34 pm

        Fr. Chad and St. Alphonso are both Thomists, too, so in his talk on chastity, he presents everything from a Thomistic perspective.

    • May 24, 2012 at 11:51 am

      If the response given to Nyssan is right, then concupiscence stands to sex as the tyrant stands to the citizens: i.e. just as tyranny consists in ordering the common good of the polis to ones own self, concupiscence consists in enjoying, as a private good, what is good because of its relation to the common good. The proportion isn’t perfect, but in this sense the difference is not a fine line. The casuistry of particular cases will probably have a few fine line distinctions, but the distinction does make for a few bright lines too: for example, anyone watching porn is certainly taking pleasure in another, as is anyone who has the sort of mentality that this comes with and generates.

      The general axiom here, I think, is that sexual activity must have something properly human about it and not be merely animal. The physical union has to build up a human society and a friendship. Failing this, there is at least venial sin.

      • May 24, 2012 at 1:41 pm

        James Chastek : “The physical union has to build up a human society and a friendship.”

        From the reading of the passage this is what I take :

        Friendship is not required. Nor does St. Thomas even allude to friendship, charity and friendship are not the same. Charity is within our control, friendship is not. Arranged marriages are not grounded in friendship but in duty.

        And while it’s finally ordered to society at large, St. Thomas orders marriage to the family where the unitive is also grounded in the family. Which in turn means that the good of marriage is within the control of the will.

      • May 24, 2012 at 6:47 pm

        If arranged marriages count as evidence against the claim you are responding to, then your argument has to be this:

        No one in an arranged marriage can act for the sake of becoming friends with the other spouse
        Arranged marriages are good

        On another point, St. Thomas defines charity as a sort of friendship, and so it’s odd to oppose friendship and charity; and he also sees friendship as essential to marriage (see the arguments against polygamy in the Contra gentiles)

      • thenyssan said,

        May 24, 2012 at 4:06 pm

        Let me take a different stab at it, connecting to your last paragraph there (“The general axiom…”)

        Based on STA’s theory of passions as I understand it, judging sexual acts “excited by concupiscence” to be venial sins is absurd. Concupscentia is nothing other than the movement of the sense appetite to a sensible good…it’s the fundamental job of the passions to excite action. He can’t consistently argue for a bloodless sexuality…if we have intercourse because we’re in the mood it’s a venial sin? Hard to swallow.

        How about this: a sexual act can’t SIMPLY be excited by concupiscence, or it is venial sin. That excitation has to lead to a will to render the debt. I think the real problem is not our understanding of the venial sin part; I think it’s that we miss the mark on what the debt is. It sounds so cold and contractual—“ok, I guess I have to do this for you, but I don’t really want to”—but in fact it’s STA’s personalist language (to reference your first comment response). So to exit without expanding on that any more, I think we get a little stuck on the middle part (venial sin) unless we really get what he means about rendering the marriage debt.

    • Alan Aversa said,

      June 1, 2012 at 12:54 pm

      “[B]eing ‘horny'” would be enough because the converse of the axiom “Qui tenetur ad finem, tenetur ad media (he who is bound to reach a certain end is bound to employ the means to attain it)” is certainly true.

      Look what St. Thomas did to the prostitute his brothers sent to tempt him. He wasn’t consenting to any feelings this woman may have aroused in him; rather, he chased her out with a burning coal to remove the proximate occasion of sin.

  4. May 25, 2012 at 1:15 am

    James Chastek writes : “If arranged marriages count as evidence against the claim you are responding to, then your argument has to be this:

    No one in an arranged marriage can act for the sake of becoming friends with the other spouse
    Arranged marriages are good”

    Arranged marriages have been traditionally recognized as valid. And since they are valid then it follows that the type of marriage cannot be defective in such a manner so as to cause the spouses to sin by doing their conjugal duty.

    Friendship may come in time in an arranged marriage, but there typically would not be a friendship at the beginning of the marriage, so friendship can’t be required to avoid committing a sin.

    The argument against polygamy is concerned with an impediment. St. Thomas isn’t saying that friendship must exist for a marriage to exist, otherwise arranged marriages could not be considered valid.

    Or if he is saying that “friendship is essential”, it’s difficult to see how he can square it with arranged marriages where over the centuries a spouses barely knew each other prior to the marriage bed.

    • May 25, 2012 at 9:21 am

      Wondering. If friendship is essential to marriage, does that prove that the visible Church erred in not granting the annulment to Henry VIII? Killing Catherine of Aragon is a pretty good sign there wasn’t a friendship.

      Or more to the point. No doubt there have been plenty of marriages where there was a friendship that later ceased to exist, but yet we know marriages don’t exist and then later cease to exist. So friendship can’t be essential to marriage.

  5. May 27, 2012 at 10:38 am

    James Chastek writes : “your argument has to be this:

    No one in an arranged marriage can act for the sake of becoming friends with the other spouse”

    Let me clarify a bit:

    They can become friends, but friendship is not essential. Friendship is proper to marriage, but not essential to marriage.

    A newly conceived baby is human even though not sighted. A marriage can be contracted even though there is not friendship.

    A man can become blind but he remains a man. A marriage can cease being a friendship but it remains a marriage.

    Polygamy would be an impediment against what is proper to marriage, not against what is essential to marriage.

    An arranged marriage is a marriage because it has what is essential to marriage which is a contract to beget children and raise children in society. But it does not have all that is proper to marriage, i.e. friendship.

    St. Thomas is writing concerning what is essential to marriage, not what is proper to marriage. Which is why he does not allude to friendship.

    St. Thomas is writing concerning what is essential to the conjugal act, i.e. charity, which is why he does not allude to friendship.

    Charity may be a sort of friendship, but that is the standard by which we judge what is a proper friendship in marriage, then St. Thomas’ argument against polygamy is very weak because a man can be charitable to many wives.

    Given such a low threshold for friendship. The argument for polygamy would be akin to : Charity is a sort of friendship, and since a man can be charitable to many wives, it follows that a man can have friendship with many wives.

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