Violence against human design is morally wrong.
Homosexuality is violence against design.
Therefore, homosexuality is wrong.
And by design we mean more than procreative design, although that goes along with it. We mean that husband and wife were designed by God for a spiritual and physical submersion into one another; a qualitative union that produces new life.
Now opponents of our argument pounce on this with an analogy.
They hear us saying, "Gay marriage is against nature because gay people cannot procreate." They respond with, "Ah, but infertile couples can't procreate."
If you can procreate, then you are acceptable to God.
You can't procreate.
You are unacceptable to God.
This is a fallacy called denying the antecedent. Of course if our argument were so simple, it would be easily discredited on these grounds.
Surely a gay couple and an infertile straight couple cannot be compared. The only thing they have in common is that they cannot reproduce. But there are at least two crucial differences:
The gay couple can't reproduce because their sexual act is teleologically non-interfertile (infertile).
The infertile couple can't reproduce because in their teleologically interfertile sexual act, something has gone wrong.
The gay couple cannot, under any conditions (say, increased fertility), come to be able to forge a union that will be expressed in a new life that organically captures the essence of the two parents.
The infertile couple can, under different conditions (say, in-vitro, increased fertility), come to be able to forge a union that will express itself in a new life that will be a reflection of the two parents.
Let me offer an analogy and then show the absurdity of this very common objection... I'll start with the argument up to date:
1. If sexuality is used according to its purpose (Aristotle's notion of teleological entelechy), then the sexual union has the potential to produce a child that is an expression of the parents.
2. Person X always desires and practices homosexual sex.
3. To fail to use one's sexuality in accord with entelechy is an act of violence against design.
4. To violate design is morally wrong.
5. Person X is morally wrong.
And now the analogy:
1. If use my legs according to their purpose (again, entelechy), then I will be capable of independent motion.
2. Person Z always uses his legs as a tabletop or a pin cushion or for the display of fashion.
3. To fail to use one's legs in accord with entelechy is an act of violence against design.
4. To violate design is morally wrong.
5. Person Z is morally wrong.
Now does it not seem plain that it would be foolish to reply to an argument like this by saying that infertile couples also can't produce children?
To say that premise one of the first case (the case of person X) doesn't hold because of infertile couples is like saying that premise 1 of the second case (the case of person Z) doesn't hold because there are paraplegics. A person who elects not to use his legs according to their function is clearly different than a person whose legs are merely broken. In the same way, a person who elects not to use his sexuality in a way that can bring about reproduction is clearly different than a person whose sexuality is merely broken.
Another possible objection:
Perhaps someone argues in response to this that some married heterosexual couples experiment sexually with forms that are less than procreative, so they must be morally wrong, or a least partially morally wrong, to do so.
Back to our comparison. If a man experiments with uses of his legs that are less than in accord with their design, which I have here suggested is "independent motion," then is he morally wrong in those instances?
Note that my argument has to do with one's disposition towards the natural function of something. This is why I used the term "always" in the premise. I wanted to reflect the notion that a gay person feels it is always acceptable to engage in teleologically non-interfertile sexuality. Or put more strongly, he feels it is acceptable in principle, universally.
For example, I think it is clear that a man who "experiments" with using his legs as a tabletop, but also recognizes that this is not really their natural function, cannot be understood to harbor a disposition of violence against design. He merely notices certain ancillary (even accidental) uses for his legs within the context of their natural use. A man who came to deny their natural use would be functioning outside nature's teleology.
In the same way, a couple that "experiments" with various forms of sexual expression, but also recognizes that this experimentation is not really the natural function of sex, cannot be understood to harbor a normative resistance to procreative sexuality (but note that Aquinas and the Catholics are much stronger here). To make this point clear, ask a typical heterosexual couple if they would be comfortable never expressing their sexuality together in ways that are potentially procreative? If they say yes, then there is really nothing different about them and the gay couple (at least as far as this argument goes).
Back to the analogy. What if Person Z came to be fascinated with not only using his legs as a pin cushion, but watching the blood flow out of them? What if he started cutting them, etc? And what if he was still walking from time to time, but his odd behavior was also making it more difficult for him to walk and was even distracting him from walking? Surely his disposition has changed! And this is perhaps a slow journey for some, but is it really unreasonable to call such a man's disposition "violence against design?"
