First Things, August 2009.
Everyone agrees that marriage, whatever else it is or does, is a relationship in which persons are united. But what are persons ? And how is it possible for two or more of them to unite? The view typically (if often unconsciously) held by advocates of liberal positions on issues of sexuality and marriage is that the person is the conscious and desiring aspect of the self. The person inhabits (or is somehow associated with) a body, certainly, but the body is regarded (if often only implicitly) as a subpersonal reality, rather than a part of the personal reality of the human being whose body it is. The body is viewed as an instrument by which the individual produces or otherwise participates in satisfactions and other desirable experiences and realizes various goals.
For those who formally or informally accept this dualistic understanding of what human beings are, personal unity cannot be achieved by bodily union. Persons instead unite emotionally (or, as those of a certain religious cast of mind say,spiritually ). And, of course, if this is true, then persons of the same sex can unite and share sexual experiences together that they suppose will enhance their personal union by enabling them to express affection, share pleasure, and feel more intensely by virtue of their sex play.
The alternate view of what persons are is the one embodied in both the historic law of marriage and what Isaiah Berlin once referred to as the central tradition of Western thought. According to this view, human beings are bodily persons, not consciousnesses, or minds, or spirits inhabiting and using nonpersonal bodies. A human person is a dynamic unity of body, mind, and spirit. Far from being a mere instrument of the person, the body is intrinsically part of the personal reality of the human being. Bodily union is thus personal union, and comprehensive personal union”marital union”is founded on bodily union….