Before he became Pope Innocent III in 1198, Lotario dei Conti of Segni wrote De quadripartita specie nuptiarum, a treatise defining marriage as a four-part thing according to the four ways that Parisian scholastics of the day interpreted Scripture: historical, allegorical, tropological, and anagogical. According to Lotario,  the “historical” was the carnal marriage of man and woman, designed for the procreation of offspring and the avoidance of fornication. The “allegorical” referred to the sacramental marriage of Christ and the Church; the “tropological,” the marriage of God and the individual soul; and the anagogical, the marriage between the Word of God and human nature in the Incarnation of Christ. For Lotario, the four types of marriages were equally “marriage.” His point was to enable each to shed light on the others–to create an interpretive web for enriching his readers’ understanding of all the relationships.

This excursus is prompted by a reading of the pastoral letter on marriage issued yesterday by the USCCB. It, too, makes reference to spiritual marriages–between Christ and the Church, within the Trinity. But unlike its medieval precursor, it tends to privilege the historical sense as the only “real” marriage. It’s not a medieval document, but I’m not sure it’s better for that. Carnal marriage–between a man and woman, sans contraception or divorce–becomes an object of transcendant significance, the bedrock of society and even of the Church. Marriage as an idol has been a Protestant temptation, and a Mormon one–but in recent years the Catholics have embraced it too.

If the Church wants to do that, it’s not for us non-Catholics to object. But it also teaches that monogamous, heterosexual marriage is a natural phenomenon, created in obedience to Natural Law, and therefore that it can intervene to try to make society at large toe the line. In that regard, the pastoral’s secular argumentation with respect to non-heterosexual marriage is notably weak–mostly just ex cathedra table-thumping like the following:

The legal recognition of same-sex unions poses a multifaceted threat to the very fabric of society, striking at the source from which society and culture come and which they are meant to serve. Such recognition affects all people, married and non-married: not only at the fundamental levels of the good of the spouses, the good of children, the intrinsic dignity of every human person, and the common good, but also at the levels of education, cultural imagination and influence, and religious freedom.

When it comes to plain old cohabitation, the pastoral refers its readers to empirical data:

Social science research, however, finds that cohabitation has no positive effects on a marriage….The findings of the social sciences confirm that the best environment for raising children is a stable home provided by the marriage of their parents.

Regarding same-sex marriage, the findings of social science are conspicuous by their absence.