When a fertile couple have children, they realize an even greater intrinsic value than that of maximal experiential union as such, for they now share experiences with their children as well as sharing with each other the experience of generating and raising children. If one were free to choose to whom one is sexually attracted and with whom one falls in love, one could simply choose the greater value. But these are not choices, and for persons unattracted to the opposite sex, as for infertile persons, the greater value is not available. Depths of experiential union, and their corresponding categorical values, are lexically ordered such that any union of two persons who are in love is deeper than that of any two who are not, even if they have reproduced. This is so not just because lack of sexual attraction will undermine and destabilize a union, but more deeply because only in romantic relationships can persons fully and reciprocally share themselves.
The norms of marriage apply to maximal experiential union. If a couple’s relationship is permanent, each party will share more of his or her life with the other than if they separate, and the expectation of permanence will give rise to a quality of no-holding-back.
Monogamy and fidelity contribute their own qualitative depth, thereby conducing to permanence. In a case of polygamy, polyamory, bigamy, or infidelity, at least one party holds part of himself in reserve for another no matter whom he is with just now, and because he might give himself more totally to anyone, his union with each is less than maximal. If they know this, it will probably dilute their disposition to give themselves fully to him.
It is only by deepening and enforcing experiential union that the norms achieve their child-welfare consequence. By ensuring that as many reproductive relationships as possible are maximal experiential unions, they ensure that as many children as possible are raised by their biological parents.
A final two norms. Maximal experiential unions should be of peers, for only peers can achieve mutual comprehension. One cannot form a maximal experiential union with another kind of animal or a child or a mentally impaired person.
Yet maximal experiential unions should be relationships of peers whose bodies/minds are complementary rather than overlapping. Part of what is stunting about facing life alone is the limitedness of one’s resources of character and ability, and this is not helped by doubling up on what one has. This final norm goes some way toward explaining why incestuous relationships cannot easily attain the good of maximal experiential union. (There are independent and much stronger reasons, having to do with the nature of blood relations and the manner in which the intensity and possessiveness of sexual desire would destabilize them, to think incestuous relationships wrong or imprudent for the individuals themselves, as well as bad enough for society that the law should forbid them.)
What of the law? Has it any reason to concern itself with maximal experiential unions?
The revisionist, even if he is conservative, may say: The legal institution of marriage does not just protect children. It also protects the good of maximal experiential union. It does this by guaranteeing recognition of the couple as a couple in their commerce with the community. Sometimes this is not so important: Will we get the couple discount at the dinner buffet? But being in a maximal experiential union involves facing major life events jointly, even if this can mean no more than that one party makes decisions on the other’s behalf, provides for the other’s care, or, in the case of death, sees to it that the other’s wishes are honored. Various social institutions play a role in deciding whether that is possible. We must ask whether, apart from considerations of child welfare, the state has any business requiring those institutions to recognize maximal experiential unions.