Tuesday, October 22, 2013

Some Clarifications of Natural Law Ethics and Human Sexuality

Natural law ethics essentially states that human beings have functions, each with a purpose.  It is morally right to foster these functions, and morally wrong to intentionally frustrate these functions.

Now with this in mind, the natural law ethicist sees the primary purpose of human sexuality as procreation, whereas the secondary purpose (still a good thing) is pleasure and intimacy.  As a result, any action that subordinates the primary purpose to the secondary purpose is morally wrong.  Therefore, not only are homosexual acts morally wrong, but so are contraception and abortion.

Of course, two objections usually surface around this time. 

Objection #1: Wearing eyeglasses and flying planes is unnatural.  These actions are morally ambivalent, so something must be wrong with natural law ethics. 

Reply to Objection #1: The objection misinterprets the fundamental axiom of natural law ethics.  The moral axiom is distinct from the laws of nature, e.g. gravity.  Neither of the actions listed as counter-examples results in a frustration of any human function.  In fact, eyeglasses actually enhance the purpose of the eyes - namely, eyesight!

Objection #2: If natural law ethics is correct, then the sex of infertile couples is morally wrong.  That is absurd. 

Reply to Objection #2: Yes, it is absurd, but not for the reason the objector gives.  You see, an infertile couple that is male and female are still fertile in kind, even though they are infertile by accident (non-essentially).  The infertile couple does not intentionally frustrate the primary function of human sexuality, whereas homosexual acts, contraception and abortion do.


  1. As a result, any action that subordinates the primary purpose to the secondary purpose is morally wrong.

    Why do natural lawyers hold this view?

  2. What if homosexuality serves a function at a societal level? Some have theorized that it plays some larger role, such as at the group level.

    If this is true, then it seems that it does have a telos, and ergo ought to be embraced.

  3. Jayman, an example might help. The primary purpose of the liver includes things like detoxification and protein synthesis. A secondary purpose is to metabolize alcohol. If the secondary purpose subordinates the primary purpose, then that almost inevitably leads to disease. Since the good is what is most desirable, and disease is not desirable, it follows that the subordination of the primary function to the secondary function is not good.

  4. Martin, I can't really comment on anything that's hypothetical or speculative. What I can say is that what is most good for the self will end up being most good at the societal level. The reason I wrote this post wasn't to criticize homosexual behavior (or contraception, abortion, etc.) per se, but rather to clarify what natural law theorists mean when they say that X is a violation of natural law. Natural law theory is so often confused with the laws of nature that I thought it prudent to make this distinction unambiguous.

  5. Let me briefly expand on my comment above that what is most good for the self is most good for society. If we take any sexual act (it doesn't have to be homosexual), and we subordinate the primary function to the secondary function, we are violating natural law. Supposing, however, that such a violation may serve the good of a society, then the human person becomes divided. On the one hand is a purpose for reproduction, and on the other hand is a hypothetical purpose for non-reproduction. If the two are both primary functions of human sexuality, then we end up with a contradiction. Either reproduction is primary to human sexuality, or else non-reproduction is. It cannot be both.

  6. Reproduction would be the primary purpose, and social cohesion (or whatever) would be a secondary purpose, but without the secondary purpose, society would fall apart and nothing would work right.


  7. Doug, becoming an alcoholic might destroy your ability to fulfill the liver's primary purpose. In that situation I see why subordinating the primary purpose to the secondary purpose doesn't make sense. But in the case of contraception, for example, fulfilling the secondary purpose does not hinder one's ability to (later) fulfill the primary purpose.

  8. Martin, I won't argue against the necessity of the secondary purpose. My only point is that, on natural law ethics, it's wrong to subordinate the primary purpose to the secondary purpose. We can have social cohesion without approving of homosexual behavior, contraception, or abortion. At least, I see no reason to doubt that.

  9. Jayman, it's not about fulfilling the secondary purpose of sex (pleasure and intimacy) that's morally wrong on the natural law ethics paradigm. Rather, it's the subordination issue. The fact is, Natural Family Planning (NFP) is over 99% affective, whereas the Pill is associated with a long list of diseases and the condom is not nearly as affective as NFP.

    One needn't just look at the liver. Take any human function, and you'll find that the primary purpose should not be subordinated to the secondary purpose. In order to make sex an exception, without being an example of special pleading, there has to be a rationally compelling reason to make it an exception. So far, I have yet to come across such a reason.

  10. >We can have social cohesion without approving of homosexual behavior

    But let's say that at some point biologists discover that homosexuality is, in fact, necessary for cohesion on a larger, structural level in non-obvious ways. What does the natural law ethicist say now?

  11. Social cohesion is arguably a secondary purpose to the functions of humanity. So, whatever biologists might say, the primary purpose (procreation) remains intact. In fact, it's difficult for me to even conceptualize a scenario in which mere biology could have any ethical implications.