Aquinas on Sexual Sins – The Dangers of Speaking Formally

Which is worse: adultery or masturbation? Rape or masturbation? Did Aquinas teach that masturbation is a greater sin than rape, because masturbation is unnatural, and rape is not? If so, what did he mean by speaking in this? The suggestion that masturbation is ultimately a greater sin than adultery or rape is immediately repellent to us. In fact it is ridiculous, yet certain authors attribute precisely this position to Thomas Aquinas, reading him to be saying that the sin of masturbation is simply speaking, ultimately, worse than the sins of adultery and rape. Moreover, the further argument is made that the Church upheld this position for a long time, and this (false claim) is used to attack the Church's credibility in sexual ethics. Doubt is sometimes expressed regarding various teachings or practices of the Church, e.g., regarding the Church's affirmation that homosexual intercourse is wrong, or the restriction of priestly ordination in the Roman Rite to those who freely choose to embrace celibacy. The argument is made that if the Church "taught for a thousand years that masturbation is a worse sin than rape", its teaching on sexual matters can't be very sound.

This misunderstanding of the Church's traditional teaching on sins against nature seems to be more prevalent than I realized. I hadn't previously realized how many authors and teachers assert that not only many medieval theologians, but even Thomas Aquinas taught this. Here are some sample quotes from books discussing masturbation in Aquinas:

[In Aquinas's view], Because sins against nature were sins against God, they were considered more serious than sins against other people, such as adultery, seduction, and rape (John F. Schumaker, Religion and Mental Health [Oxford University Press US], 1992), 76).To make his point perfectly clear, Aquinas poses a question: are not rape and adultery worse than unnatural acts, since they harm other persons, while consensual sins against nature do not? The answer is unequivocal: the four non-procreative forms of sex are worse, since–though not harmful to others–they are sins directly against God himself as the creator of nature. According to this logic, rape, which may at least lead to pregnancy, becomes a less serious sin than masturbation (Louis Crompton, Homosexuality and Civilisation, [Harvard University Press, 2006], 188).

"A practice opposed to the pattern set for us by nature" exceeds in wickedness the seduction of an innocent of the opposite sex, adultery, and rape (II-II 154:12) (Sex from Plato to Paglia, by Alan Soble [Greenwood Publishing Group, 2006], 1053).

One unfamiliar with the scholastic manner of speaking formally about an issue, that is, addressing precisely the question at hand, might easily get this impression from Aquinas's treatment of sexual "sins against nature."

Here is the text itself. In the Summa Theologiae II-II, q. 154, a. 12, Aquinas says:

In each kind of thing the worst corruption is the corruption of the principle on which other things depend. Now the principles of reason are the things in accord in nature… and therefore, to act against what is determined by nature, is most serious and base. Therefore since in the sins against nature man transgress what is determined by nature in regard to sex, the sin in this matter is the gravest kind of sin. After this is incest… while by the other species of lust one transgresses only that which is determined according to right reason, but presupposing the natural principles. But it is more contrary to reason to have sex not only contrary to the good of the offspring to be born, but also with injury to another. And therefore simple fornication, which is committed without injury to another person, is the least kind of lust.

The first objection of the article argues that sins against nature are not the worst, because they are not the most contrary to charity: "The more a sin is contrary to charity the graver it is. Now adultery, seduction and rape, which are injurious to our neighbor, seem to be more contrary to the love of our neighbor, than unnatural sins, by which no other person is injured. Therefore sin against nature is not the greatest among the species of lust." St. Thomas replies to this objection: "As the order of right reason is from man, so the order of nature is from God himself. And therefore in sins against nature, in which the very order of nature is violated, injury is done to God himself, the one who ordains nature."

Aquinas is focusing on the sins precisely as a violation of the right use of sexuality, and abstracting from other aspects of them. As justice is a greater virtue than chastity, so injustice is a greater evil than unchastity, and thus all things considered, Aquinas would consider rape a greater evil than masturbation or contraception. This formal way of speaking is recognized by some more considerate authors:

The teaching of medieval theologians that such sexual sins as masturbation, sodomy, and contraception are more perverse, as sexual sins, than fornication or adultery or even rape (the former were said to be contra naturam whereas the latter were said to be praeter naturam), angers many people today. But this teaching must be understood properly. The medieval theologians are claiming that certain kinds of sexual sins more seriously offend the virtue of chastity than do others. They are not saying that these sins are for this reason less grave as sins than adultery or rape, for instance. After all, adultery and rape are very serious violations of the virtue of justice as well as being violations of the virtue of chastity. Thus, as a sin, rape is far more serious than masturbation or homosexual sodomy because it not only offends chastity but also gravely violates justice. (Ronald David Lawler, Joseph M. Boyle, William E. May, Catholic sexual ethics: a summary, explanation & defense).

It is important to understand this formal way of speaking, considering one aspect of human behavior and abstracting from other aspects. But as Aquinas himself says in another context, "where such a manner of speaking is found in the writings of an authority, one should not continue to speak in this manner, but should piously explain what is said" (Summa Theologiae I, q. 31, a. 4, loose translation).

In regards to the comparison between fornication and masturbation, St. Thomas may have in mind fornication in an instance where there is a potential marriage between the two persons (even if they are not engaged), since otherwise it would be contrary to the good of the offspring who might be born. Whether he had this in mind or not, it does seem to me that there are many cases where fornication is worse than masturbation, on account of the harm done to the other party, and on account of the potential harm of children conceived and born as a result (e.g., if they are thereby deprived of the presence of one parent in the home).

The Reception of Thomas Aquinas

I would agree that Thomas Aquinas's classification of sins as received by moralists in following centuries became a problem, in part because it was not used formally, but materially; that is, the descriptions of sins and the various gravity of different sins or aspects of sins were applied directly to physical, material acts. Even Alphonsus Liguori, named the patron of confessors and moralists by Pope Pius XII, seems to have fallen into this error. And in this respect I do see problems with the Church's usual approach to sexual morality for centuries, not sexual morality in particular however, but simply morality in general, the tendency being to take an extrinsic, legalistic approach to morality, and to focus on sins, rather than an approach focused on the real nature of human goods. This was to some extent an outgrowth of nominalism, which made of natural law a kind of arbitrary imposition by God's will. In another post I'll come back to this general topic of legalistic morality.

Update:

I gather from the questions that bring people to this post that this anachronistic reading of Thomas Aquinas (and the other scholastics) is a common one. Aside from some general queries such as "contra naturam in Aquinas," or "Aquinas' thoughts on rape," or "Aquinas on sexual morality," "Thomas Aquinas on masturbation," "Aquinas' views on rape," there are a number of questions that suggest having encountered such a view:

1. When did rape become worse than masturbation? (Related questions: Rape is not as bad as masturbation? Is masturbation a greater sin than rape? Masturbation worse than incest? Which is worse, masturbation or adultery?)

It was all along. But if the question is meant in the sense "when did people stop making technical lists of how fundamentally an act goes against the sexual purpose of the genital organs?", the answer is, "when they in general stopped making such technical lists."

2. Is masturbation worse than fornication? (Similar related queries: Is masturbation a greater sin than having sex? [This must mean "having sex" outside of a marital relationship.]; is masturbation better or worse than actual intercourse?)

In most cases not. First, as noted above, in the many cases where the present relationship or the capacity for a committed and unselfish relationship in the future is seriously harmed, or where danger to offspring is present, fornication is objectively graver. Moreover, masturbation requires, and in most cases involves, a much less deliberate act of will than fornication does, and therefore the sin is any case subjectively less bad.

3. The catholic church taught that masturbation is worse than rape because at least the latter might result in conception. (Related questions: Rape is much less a sin than masturbation. Masturbation is worse than rape? [Did] Aquinas [teach that] rape is better than masturbation?)

No, it didn't.

4. Is masturbation worse than adultery?

No.

22 Responses to “Aquinas on Sexual Sins – The Dangers of Speaking Formally”

  1. Anonymous says:

    Joseph, this is something that constantly needs to be repeated. Great post.

    Cheers.

  2. Anonymous says:

    What you have done is the Catholic habit of never conceding a thing…always explain away that an authority might have been wrong. br Aquinas was simply wrong in reverse. Adultery is against the natural law as is rape. What you have him saying here is that adultery is not against the natural law but sodomy is. This is a bizarre moment for Aquinas since he was usually broad with the concept of natural law. He mistakenly followed Aristotle in forbidding the tiniest interest on a personal loan as being against nature. So this means that he saw even 1% interest as against nature (later appearing in Vix Pervenit by a Pope to the Bishops of Italy only) but he saw rape in accord with nature because a child could be born…because the act itself when stripped of its injustice…was natural.br Hence there is a confusion here of natural law versus against nature within Aquinas.

  3. Anonymous says:

    Could you explain how God can be injured as Aquinas notes here in a passage that you cite:

    "And therefore in sins against nature, in which the very order of nature is violated, injury is done to God himself, the one who ordains nature…"

    I thought Aquinas held that God..excepting the Incarnation… cannot suffer since this would entail change and there is no change in God since He does not have the lower part of the soul in which changing emotions take place within humans.

  4. Joseph Bolin says:

    Funny how a single, individual explanation becomes a "habit of never conceding a thing… always etc." Thinking I misread Aquinas, you seem to assume it is from an unwillingness to admit he was (or even might have been) wrong. Wouldn't it be just as reasonable, or even more reasonable, to suppose that I simply made a mistake in reading Aquinas? In fact, I have no hesitation about expressing doubts or disagreements with Aquinas. But I also have no hesitation about interpreting him in the manner that seems to me correct, as I have done in this case.

    The term "natural law" occurs neither in my post nor in this article of Aquinas. The confusion of "natural law" and "nature" is present neither in Aquinas nor in my post. Aquinas knows perfectly well and affirms that adultery is against natural and divine law. But that is not the issue in this article. He is here speaking of vitia or peccata contra naturam, which are understood to be contrary to the nature which is, so to speak, merely nature, namely animal nature, in contrast to human nature as such. All sins are against natural law, but not all are contrary to nature in this quasi-technical sense. (I say quasi-technical because even in ordinary speech people make a somewhat similar distinction.)

  5. Joseph Bolin says:

    If you desire response or discussion, please continue with a pseudonym, rather than simply being "anonymous." There are already two "anonymous" commentators on this post.

    It is partly a question of translation, partly a question of analogy. The Latin term there is "injuria", which was translated "injury", as the English correspondent. In fact the term can mean "injury" in the sense of a real harm done, or "injustice." The English "injury" still retains the notion of injustice in legal contexts.

    It is also a question of analogy. Not all injury implies a real change to the injured party. It can involve merely not giving someone what is due to him, or acting in an inappropriate way in regard to him (e.g., a man who takes photographs in violation of a person's privacy does injury to that person, even though one could say he doesn't actually do anything to him or her), and this is the sense in which it is used in reference to God. Aquinas in I-II 21:4 takes up the objection that good or bad human acts are not meritorious or demeritorious before God because "a good or bad act of man does not result in benefit or loss to God himself." Aquinas responds that "by man's act nothing is gained or lost for God in himself, but man, as far as concerns him, withdraws something from God, or gives something to him, when he keeps or does not keep the order which God established."

  6. Mark says:

    Good work Joseph. I found your post searching for a Thomistic discussion of the difference between sodomy and adultery/fornication. That wasn't precisely your intent, but close enough.

  7. Joseph Bolin says:

    Thanks Mark. I suppose you were also looking for a discussion regarding the relative gravity/evils of those sin, so it is pretty similar.

  8. Tim says:

    I have a question about sex between a husband and wife. If a husband and wife consent to any type of sex between themselves and do not involve anyone else in any way (ie: telling others photos etc.)is that a sin?

    Recognize that Biblical prohibitions are intended to protect something precious not deny something pleasant.

    Everything I have read on sexual sin is for singles and not a husband and wife. I would like to know your comment/take on this.

    Thank you and God bless you.

  9. Joseph Bolin says:

    Tim, if I understand rightly, you are asking whether certain kinds, or a certain kind of sex between husband and wife is a sin. You may have in mind oral sex, mutual masturbation, or other such things. I get the impression from your comment "recognize that biblical prohibitions etc." that you feel some Christians are too strict in regard to what is lawful and fitting in the sexual relationship of spouses. But without a specific question, I can only give a general answer.

    Basically, a kind of sex that harms human persons, destroys fundamental human goods, is bad. If a husband, due to neglecting to consider his wife's feelings, has sex with his wife in a manner that seriously harms her psychologically, that is a sin, even if his wife doesn't perceive the harm, and consents to that manner of sex. The same thing applies to the wife. Of course it is also sinful to have sex in a manner that is physically harmful to one's spouse, but I mention psychological harm first, because that possibility is more frequently overlooked.

    A second point: the relationship between husband and wife is fundamentally marked by the natural order to fruitfulness in the union of male and female. Hence, types of sex that reject this fertility are harmful to the relationship between husband and wife, and also deny the goodness of procreating children that is implicit in this relationship.

    Putting these two points together, types of sex that are reject the fertility of man and woman are sinful. Oral sex alone, even if both spouses consent, is contrary to the genuine marital union of the spouses, and the good of children. However, oral sex and other types of sexual activity that cannot of themselves lead to procreation may be legitimately part of the sexual union of husband and wife, coming before or after the union that is the kind of union which in principle is able to be fruitful. (The reason for adding "in principle" is to make clear that sexual intercourse in times of infertility is legitimate, even though no new life could come about in that concrete case.)

    To summarize, sex that harms husband or wife, physically or psychologically, or that denies the fruitfulness for life of husband and wife, can be sinful, and is sinful if this harm or denial is deliberate or due to negligence. As you point out, prohibitions are intended to protect what is precious… the relationship between husband and wife, and their relationship to children.

  10. Tim says:

    Thank you for your information. My wife can not have any children (hysterectomy). So the kind of sex we have is for pleasure between the two of us. I was wondering if there is anything wrong with that. No we do not harm each other in any way. We truly love each other in Christ, and would not could not even think of any type of harm to each other. Again thank you for your information and may God bless you in all you do.

  11. Tim says:

    I re-read your post and understand it better now. I thank you again for the input and information. God bess you.

  12. LRTSR says:

    Would masturbation constitute a loss of material virginity? Of formal virginity? Of both?

  13. Sam says:

    I believe Aquinas's meaning of fornication in Article 2. only included "simple fornication", which in his context probably meant 'unmarried sex between two people, and one of them is a prostitute'. I don't think he included the idea of "engaged couples" into his writing.

  14. Jeremiah says:

    Stumbled upon your website. I know this is an old post, but I commend you for it. I also encountered an ex-Jesuit seminarian over dinner who mentioned this very thing, about masturbation being worse than sex, but he attributed it to Augustine (though from my impression, he could have attributed it to any medieval theologian). I'm very glad to know that this is not the case, and that this is a misunderstanding in reading Aquinas.

  15. Elizabeth D says:

    Sam, if engaged couples fornicate it is nontheless gravely contrary to chastity, and excludes them from receiving Communion licitly until the sin is sacramentally confessed and absolved. Many today make little attempt to hide their violation of chastity but cohabit and fornicate with someone they might or might not eventually marry (public concubinage). They risk giving bad example and scandal: because of the timing of the birth in relation to the wedding, it will presumably become publically known that the couple had premarital relations (although when this sin is compounded by contraceptive use, surely it is more serious rather than less so). There is also the serious risk of harm to offspring and being deprived of family life with married mother and father, if the couple winds up not marrying. And the individuals' willingness to have extramarital relations before marriage is a poor preparation for abstinence from extramarital relations after they are married. Chastity before marriage respects the sanctity of marriage and the dignity of the man and woman, and is the appropriate and best training and foundation for real and total self-giving of the spouses and conjugal chastity within marriage.

  16. Ian says:

    You can tell it is good because we are still reading and posting on it : )

    Thank you for your honest and reasonable defense of our beloved Church.

  17. Ian says:

    Just in case anyone else was interested, you can read the rest of the Article, (Whether the unnatural vice is the greatest sin among the species of lust?) here http://newadvent.org/summa/3154.htm

  18. Ian says:

    This past Sunday we revisited the readings Ezekiel 33:7-7, Romans 13:8-10 and the Gospel according to Matthew 18:15-20. In his Homily our Deacon recounted St. Paul's epistle and reiterated "Love does no evil to the neighbor; hence, love is the fulfillment of the law". The idea was that there is a sort of catch all. One common objection I hear to religion in general is that people overcomplicate things and lose sight of the meaning. I do not agree per se, but I am glad Jesus spelled it out for us anyway. If you love someone you do not do any the things we have been quibbling about in this blog… At that point the severity of the various offenses almost becomes a mute point. Then I think the open and humble heart, is healed by God to whatever degree is necessary.

  19. Climacus says:

    I appreciate your defense of Thomist thought regarding sexual ethics here, (mostly because what you elucidate is what I wish were true) – but as I carefully read and re-read Q154 in the summa, I'm not so convinced Lawler, May and Boyle are correctly interpreting what Aquinas is saying here. Allow me to defend my premise:

    The thrust of Boyle's argument, that, "Thus, as a sin, rape is far more serious than masturbation or homosexual sodomy because it not only offends chastity but also gravely violates justice" seems to neglect that the emphasis that Aquinas puts on, "the sins against nature".

    Aquinas makes himself clear by echoing Augustine that, "…of all these" (the sins belonging to lust) "that which is against nature is the worst." The reason for this is is given in his reply to objection 1:

    "Just as the ordering of right reason proceeds form man, so the order of nature is from God Himself…" That is to say that a sin contrary to charity is in no way worse than a sin contrary to nature. In fact, Aquinas seems to be pointing out that a sin contrary to nature may be in fact worse than a sin contrary to charity, because such a sin, "does injury to God, the Author of nature." Aquinas goes as far as to invoke Augustine's condemnation of those who violate nature: "Those foul offenses that are against nature should everywhere and at all times be punished, such as were those of the people of Sodom."

    As we know, the people of Sodom were utterly destroyed.

    Aquinas goes on in objection 2 to show that sin against nature is worse than the sin of sacrilege:

    "Vices against nature are also against God… and are SO MUCH MORE GRIEVOUS THAN THE DEPRAVITY OF SACRILEGE, as the order impressed on human nature is prior to and more firm than any subsequently established order."

    Now, you use the word "justice" to describe the antithesis of sacrilege. In other words, Aquinas's use of the word sacrilege is synonymous with what you would call "injustice". Therefore, to counter your argument, Aquinas may be re-read as such:

    "Vices against nature are also against God, as stated above, and are so much more grievous than the depravity of *injustice*…"

    The way that Aquinas spells out his argument seems clear, concise, and without ambiguity. It seems to be that he is clearly stating that injustice against another human is not worse than, and in fact may be less than, an injustice against nature.

    Hope I'm missing something,
    Climacus

    • Joseph Bolin says:

      I will make a fuller reply later. For now, note that Aquinas asks about many sins whether they are the worst sin: infidelity, blasphemy, idolatry, despair, hatred of God, avarice, pride. He says about all of these that they are the greatest sin in some way; about blasphemy and idolatry he says without restriction that they are the greatest sin, and speaking about idolatry and pride, even does so against objections that say that hatred of God is worse.

      In contrast, Aquinas never says that the sin against nature is the worst sin, but that it is the worst sin among the species of lust.

      When he categorizes types of sin, he says that sins against God are the worst, then sins against one's neighbor. Among sins against one's neighbor, those which are against actual life, such as homicide, are the worst, then those against life in potency, as the sins of lust are.

      Now, mortal sins of violence belong to the same kind of sin as homicide, and thus will be as such worse than the sins of lust.

  20. Tancred says:

    You'd do better to show how the aforementioned sexual sins against nature are not contra nature rather than relying on contemporary sentiment to attempt to undermine the foundations of the natural law.

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