It’s not often that you find “Damian Thompson”:http://blogs.telegraph.co.uk/ukcorrespondents/holysmoke/sep07/archbishopsdeadlymessage.htm and “PZ Myers”:http://scienceblogs.com/pharyngula/2007/09/evil_catholic_propaganda.php singing in the same choir but they are both shocked by the Roman Catholic Archbishop of Maputo “who has claimed”:http://news.bbc.co.uk/1/hi/world/africa/7014335.stm not only that condoms don’t prevent AIDS but that they actually cause it, since two un-named European countries are infecting them with the virus in order to kill off Africans.
Even I, who like to believe that I cannot be shocked by anything any prelate does, was shocked by this; I suppose because what he said was so incredibly _stupid_ as well as wicked and while I am not in the least surprised to find an African archbishop being wicked about sex, I am surprised to find Roman Catholic prelates stupid and ignorant as well as malevolent.
But then I looked at the thing from the point of view of cultural evolution,a nd it all made sense. If one of the reasons for the persistence and universality of religions is that they are good for people, by uniting them into co-operating groups which flourish at the expense of rivals — and there is a lot of evidence for this — then it follows, from simple evolutionary logic, that there are two main ways in which you can outcompete the competition: by doing better yourself, and by ensuring that they do worse. Combinations of these methods are, of course, allowed, and may be inevitable.
Now, if we have a sexually transmitted plague, the thing that determines survival rates is, as much as anything, behaviour. Religions are pretty effective at influence behaviour — something that we often lose sight of because they don’t influence everyone’s equally. But when you get such astonishing statistics as that an African-American male who attends church has a life-expectancy _eleven years_ greater than one who does not there are only two explanations: either God looks after his own, or church attendance makes it much easier to avoid self-destructive behaviour. Since we discard the first one, that leaves the second. Sober, prudent, hard-working people prosper, on the whole, and religion helps them maintain these virtues because it establishes these as group norms. (Yes, yes, I know that they can persist in the absence of religion: Massachussetts and all that. My argument requires only that some forms of religion affect behaviour in this way; not that religious belief be the chief or only factor)
So, behaving in ways that minimise the likelihood of sexual transmission is something that religions might promote among a subset of believers. It is perfectly, undeniably, true that Aids could be stopped tomorrow if only everyone were either celibate or monogamous as the Catholic Church demands they be. Of course, the vast majority of Catholics are not. Theologically, this may not matter, but epidemiologically it does. The virus, unlike God, does not forgive you if you are very sorry afterwards. But, for that subset of Catholics for whom doctrine really is a behaviour modifier, being faithful to the church will protect them from Aids. In the long run, this will increase the proportion of Catholics in the population. By marrying other good Catholics, they can be sure that they won’t catch the virus. Their children will grow up healthy, with fuctioning extended families and all the benefits they bring, as well as — other things being equal — two living parents.
Again, there is a historical precedent for this, among the puritan settlers in America, who left an extraordinary number of descendents, in part at least because their religious beliefs demanded monogamy and fertility.
But at least in theory, the most effective way to maximise your group’s benefit from the plague would be to ensure that you avoided the behaviour that made you vulnerable — and that everyone else indulged in it to the maximal extent. The Christian response to Aids in Africa seems to me to follow this pattern. If what you want to do is to minimise suffering, and maximise the chances of the epidemic being controlled, then, obviously, the sort of programmes once adopted in Uganda will work best, You find out scientifically how the disease is spread, and carefully offer the minimum kind of behaviour modifications to control it.
But if your aim were to maximise the benefit to your group from the epidemic, then you would want to pursue something like the Catholic strategy. Set up one group who will be almost entirely immune — the abstinence and monogamy scheme. Let’s face it, this works, for the people who can manage it. Then ensure that everyone who practices a different strategy is maximally likely to die: this, obviously, is the effect of the campaign against condoms. In fact, the idea needs a little refinement. For real selection to work, you need the outgroup to be maximally likely, not just to die themselves, but to have their grandchildren die without issue. That seems to be the effect of the AIDS epidemic in Africa.
The fascinating thing, from this analysis, is that the Archbishops’ teaching will tend to maximise differential survival between groups – but the boundaries between the groups involved won’t exactly be those between Catholics and pagans. So far as we can tell, most Catholics dn’t in fact live up to the teachings of their church on sexual morality (and that includes priests). Lots of Catholics will die as a result of his teachings. In fact, the bad catholics (who none the less believe the Archbishop when he says that condoms are lethal) should be the group who are most vulnerable to his sermons. You might think this would work to diminish the popularity of Catholicism, or even the numbers of notional Catholics. But I don’t think this follows at all. For one thing, the other benefits of group membership are available even to promiscuous Catholics; for another, the language of sin and forgiveness tends to conceal the hard, savage edges of the actual policy.