Suppose it is true that there are natural meanings to our corporeal acts, independent of and prior to any additional meanings we choose to confer upon them. To what degree am I accountable for the natural meaning of my acts? To take a common example, let us admit that sexual intercourse has a natural meaning and purpose, that it is about procreation via family, binding generation to generation and husband to wife, and expressing a radical donation of self to one’s spouse. Are men and women always obliged to mean all this whenever they engage in the conjugal act? Must I mean what my body means?
One position would be that natural meanings have, of themselves, no moral import. This would salvage the liberal position, even after admitting natural significations. Most liberals would frown on a man deliberately promising lifelong fidelity to a woman without meaning it. On the other hand, they would insist that what the two parties understand by the conjugal act is the only morally relevant data. A man and a woman who wanted the incidental pleasures of sex without the commitment the act implies could just agree not to mean by intercourse what intercourse naturally means.
This position has the advantage of allowing all sorts of indulgences while attempting to maintain some moral standards. As a way of relating to one’s body and its given “language” for expressing love and intimacy, though, this is very unsatisfactory. It implies a practical Cartesianism. My ego or self is conceived as an entirely separate thing from my body, a thing that I am said to “own” the way I own my furniture. But my body is my interface with the world and my fellows; in separating myself from it, I separate myself from them. A lover doesn’t see me, doesn’t touch me, isn’t close to me; she only sees, feels, and embraces my body, an automaton I control but that is too separate from my “self” to be a true locus of intimacy. What’s more, the choice of whether or not to endorse natural meanings is one that we never approach in a contextual vacuum. The natural meanings are always given. They provide a context that conditions any other meanings we choose to affirm. If I have sex with a woman without marrying her, I am rejecting her as my wife and treating her as unworthy of that commitment. I can’t object that marriage was a proposition never brought up, and therefore never rejected. The act of intercourse itself brought it up by natural signification. At that point, the only choices are to consciously endorse the body’s promise or to repudiate it. If you want to not marry a woman and not reject her, there is only one way: don’t sleep with her.
The most obvious alternative would be to acknowledge a duty to always consciously mean by an act whatever that act naturally means. This is closer to the natural law view. It would mean that, before I perform an action, I should consider the natural meaning, translate it into a series of propositions of the kind I can mentally affirm or deny, and then affirm them all while performing the action with a clear conscience. This view certainly respects the language of the body; in fact, it errors in being too conscientious. Must we really expect every young bride and groom to enumerate in a set of clear propositions the whole meaning of marital love, in all its depth and force and subtlety, before they are allowed to consummate their marriage? I have certainly never done such a thing, nor do I believe that any philosopher or saint has ever done it; I doubt the thing could be done at all.
One important problem is that natural acts and relations like marriage are only really understood from the inside by engaging in them and being mentally shaped by the experience: “conatural knowledged”, as the Thomists call it. No doubt the bride and groom must have some idea what marital love means, or they couldn’t meaningfully promise it, but their understanding of it is expected to grow as they live it. Living marital love forms the mind and the imagination, so that one can more fully understand what it is that one initially promised. To expect full understanding from the start would have things backwards.
More fundamentally, the second approach falls into the same rationalist error as the opposite, liberal, position. It assumes that the only kind of meanings are the kind that can be reduced to finite sets of propositions. This, however, is not true, as we know from the philosophical investigation of art. A work of art is certainly meaningful, and may even have a “message”, but the meaning can never be completely captured by a verbal explanation; explanations of what the artwork “says” never really capture what it shows. Natural meanings are another case of showing rather than saying. They contain propositions, but they are not exhausted by them. They are in a sense larger than our minds. What’s more, the fact that something is expressed naturally rather than verbally/intellectually is itself significant. If a couple were to read off to each other all of my statements about the meaning of sex, this would not be identical to actually performing the marital embrace.