Virtually every healthy human adult on the planet has a sex life of some sort, and the effect of Thomistic sexual ideology (use sex organs for procreation only), were it to be seriously followed everywhere, would be the generation of larger families. There’s a reason that those promoting a deceleration of population growth globally see problems with the Catholic Church’s stance on condom distribution in poorer countries (for example).
I don’t necessarily agree with those promoting population deceleration, but the effect of religious ideologies on the question is clear (most especially in Islam and Christianity).
By 2100 demographers tell us that 90% of the human population will live in cities. Urban mores are simply not very conducive to the sorts of sex restrictions promoted by traditional Thomism. Niche groups of Catholic conservatives might be able to maintain the old time religious values on sex, but it’s largely unattractive (and too difficult) for most.
Perhaps the model for future Catholics will be to study the Hasidic enclaves in New York, for how does one maintain traditional Catholic values in the midst of big cities? The shutting of 50 parishes around NYC this past week suggests it isn’t easy.
Catholicism works best (obviously) for rural societies where women are not equal to men and teens are married off by age 15. The lives of women professionally would be profoundly restricted by adopting Thomistic notions surrounding sex, and the urban future is going to belong to white collar women delaying and controlling their fertility for careers, etc. (The demographics and sociology of this is well covered in Hanna Rosin’s book, The End of Men.)
But it’s also obvious that there needs to be people in the world who believe deeply in an ideology of reproduction and big families. Western countries are trying to strike a balance here. Gays and women (for example) are protected in their rights for the first time in human history, and those who want to raise large families and adhere to old school religious ideologies like Thomism are free to do their thing as well. Let freedom ring.
My own evolving take is that, much as I think it would advance the liberty of gay Catholics to have a religion that let them marry within the Church, there’s also a part of me that says the following: Catholicism has evolved a pretty successful cultural strategy for maintaining its percentage of population at around 15-20% of the globe, and somebody’s going to need to make babies in the West if too many urban professionals largely opt out. So let a thousand evolutionary strategies bloom. The big brain can do its thing in the city centers, science labs, universities, and marketplaces, and religious communities can reify their way of life as the “best and most natural.” In this way, our species benefits from the best of both worlds. Let gays, professional women, and traditionalists bloom. It’s the sort of “rapprochement” that is evolving anyway. Who’s going to stop it? Why would we want to?
And within the Church itself, it may be too much to expect traditionalists to not jump ship if Thomistic essentialism is abandoned or relaxed too much. Conservative Catholicism is at bottom patriarchal and oriented to making large families. It’s attractive to conservatives for these reasons. Conservatives don’t want women priests, gay marriage, divorced people taking communion, teens masturbating without guilt, etc., and they’ll vote with their feet and funds if the Catholic Church ever goes down such a road.
The bottom line here (for me) is that Thomists may be correct that things have “real essences,” but when it comes to the real essence of the human brain and what should be its prerogatives and orientations, the question is by no means straightforward, but complicated, and to acknowledge the degree of complication underlying our own evolutionary strategy (delay fertility for longer goals, etc.) would decelerate the Catholic population. Thomists therefore simplify narratives around the “right use” of the brain, penis, and vagina in a way that doesn’t rock the demographic and traditionalist boat for Catholicism, thereby committing them to a form of fake essentialism on matters of sex.