Did Thomas Aquinas rate masturbation as a greater sin than rape?

Question

It is sometimes said that St. Thomas Aquinas taught that rape is a lesser sin than masturbation. Is this actually the case?

Here are two examples:

[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).

What is the source of this notion, and is the statement true in context? If it is, what led Aquinas to this conclusion?

Answer 1

Here is what Aquinas actually wrote:

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.

Summa Theologiae II-II, q. 154, a. 12

It's from a passage where Aquinas is talking about different kinds of sin. There are, for example, sexual sins; sins against justice; sins against charity; sins directly against God. Any sinful act can fall under one or more categories.

Aquinas' point is that, considering only the sexual element, an unnatural act is worse than a natural one, and that's why he says masturbation is a worse sexual sin than rape. However masturbation is essentially only a sexual act, and rape has other sinful elements - it is also a sin against justice and a sin against charity.

It's like we are grading sins on many scales. Masturbation scores worse than rape on the sex scale, but it doesn't score at all on the charity or justice scales. Rape on the other hand scores moderately on the sex scale, but very badly on the justice and charity scales. Overall, rape is worse than masturbation. The church has never taught anything different.

Most of this answer is taken from: Aquinas on Sexual Sins

Answer 2

In Question 154. The parts of Lust, Aquinas orders them in descending order: masturbation, incest, rape of a wife, rape of a virgin, adultery.

The reason he gives is "In every genus, worst of all is the corruption of the principle on which the rest depend".

He's not judging based on "a sexual matter" as well as "other sinful factors". He isn't saying that masturbation is -100 for being against nature, rape is -0 because it's not against nature, but rape is -200 because it's violent.

Aquinas is saying that crimes against nature trump all other ways something is considered a sin. Nothing else need be considered, if it's against nature. Nothing compares in offense to being against nature, in Aquinas' opinion.