The contrary view of sexual activity to the one advanced by the sexual revolution is one defined by a vow. In one sense this is obvious: the sexual revolution rejected the idea that sexual activity is defined by marriage, and marriage – at least before it was modified by the sexual revolution – is a vow. But vows are contrary to the revolution in a subtler and more fundamental way – here I’m thinking of Foucault’s arguments that the sexual revolution was about self-definition, or Casey’s claim that it finds its justification in our right to define our own existence. A vow, on the other hand, sets up fixed limits and a moral structure that are incompatible with continued self-definition. Another way to put the problem is to see it as two different opinions on what it means to define oneself. When one defines himself by a vow, the sense is that he specifies intrinsic limits, unchangeable elements, and broad and even infinite domain of actions that are intrinsically harmful to the structure that exists by the vow. Defining sex by vows thus defines broad sphere of sexually immoral actions. The sexual revolution, by contrast, didn’t recognize any sexual acts as immoral – except perhaps its very logical repugnance to defining sexual activity by marriage (to remain a virgin until marriage, for example, is taken as a mark of shame indicating personal turpitude or immaturity.)
The clearest objection to vows is that we simply lack the intelligence to make them. The future is unknown to us and therefore includes contingencies that we simply cannot plan for but which a vow cannot avoid tying us to. Who can be sure his wife won’t become crazy, catatonic, or perhaps just less fulfilling than someone or something else we might discover later? Again, even if the future were not contingent, the immaturity and necessary lack of marital experience seem to make marital vows crazy. Why not just try it out for a while and see if it works? In light of this, vows need to be underwritten by a power beyond ourselves. Social structures and safety nets certainly help, but the fundamental thing we need is the confidence that there is some purpose to sticking with the vow, no matter how pointless or harmful it might appear in light of present circumstances. But no human knowledge or structure could underwrite such a claim. And so the vow is really only reasonable from within a worldview that includes the providence of a benevolent God. The multitude of worldviews opposed to this – whether atheist or theist (like Epicurianism, some humanisms, or deism) might very well still have vows, but they could only be frightening and terrible things that, for all we know, might turn out to be suicide pacts. They cannot underwrite the claim that a vow is good things to the individual that makes one.
If a society is secular it has to decouple sexual activity from vows, and thus from marriage. The logic of the consequence stays the same, whether we use it as a basis of modus ponens or modus tollens.