Against Practical Pro-natalism
Is it reasonable for philosophical antinatalists to be practical pro-natalists?
Suppose you're a vegan concerned about wild-animal and insect suffering. Reading the Guardian one day, you learn that “cattle ranching” in Brazil, supplying the flesh of cows all over the Western world, is responsible for massive destruction of the Amazon rainforest. It occurs to you that the Amazon rainforest is teeming with wildlife, perhaps moreso than any other land area on earth. Curious about what effect the Amazon's destruction might have on wild-animal suffering, you search for information on this topic, and come across this article by Brian Tomasik, learning that it would reduce wild-animal suffering. The article states its conclusion, backed by reams of evidence:
The conclusion is that rainforest-beef production probably reduces wild-insect suffering. In fact, purchasing one kg of Brazilian beef prevents 2.7 * 10⁵ insect-years of suffering as a median estimate and 5.8 * 10⁶ insect-years in expectation.
And in another (emphasis added):
If someone insists on eating meat, I would recommend eating rainforest-raised or grass-fed beef. Rainforest-grown beef plausibly reduces net animal populations because rainforests have such high productivity.
In light of these revelations, should you, a philosophical vegan, become a practical non-vegan?
Or should you have children instead?
Bentham’s Bulldog, in a tweet, has an analogous argument against antinatalism:
If you're concerned about wild-animal suffering and philosophically anti-natalist I think you should be a practical pro-natalist, because humans reduce wild animal populations by a lot.
I believe that this argument is sufficiently analogous to the scenario outlined above that we can use reductio it:
Being practically pro-natalist implies that one should also be practically non-vegan.
Being practically non-vegan is very silly.
Therefore, one shouldn't be practically pro-natalist.
Cost and efficiency
An immediate counterargument to these scenarios is that we can simply skip the evil in the middle and pay for rainforest destruction directly, using mechanical means. If we had the means to achieve the same effect, for the same cost or less, without resorting to buying flesh, we would have a reason to not accept practical non-veganism. The same is true for practical pro-natalism—if we could achieve the same amount of environmental degradation for whatever it costs to raise a child or less, there would be no reason to accept practical pro-natalism.1
It turns out, though, that cows are unusually effective at eating grass, and the immediately obvious replacements available might only be equally cost effective, or even less cost effective. Tomasik states:
But it remains interesting that beef production, which isn't intended to remove insects, may be more cost-effective than directly covering land. I guess this reflects the fact that fires and cows are some of the most efficient ways to remove vegetation from an area.
The same might hold true for children—thinking of a way to more efficiently destroy the environment other than through having children seems to be a very difficult task. One of the advantages having children has over other interventions is that they're somewhat “self-replicating”, i.e. have some chance of having children of their own; and they and their children, even if they do not share any of your values, will, by virtue of being consumers in an industrial society, be responsible for a lot of environmental destruction (and thus, reduction in wild-animal suffering). If they do happen to share any of your values, they will in addition donate a portion of their own income to causes you care about, and if you get really lucky, these donations might amount to more than whatever you spent raising them (it takes about $297,000 to raise a child over 18 years in the United States).
Nonetheless, it is still quite plausible that there would be better and cheaper ways to achieve what we want without having to fund factory farms or have children. Rapidly emerging technologies, such as genetic engineering or autonomous machine learning/AI agents, might help with this. One could burn down forests and populate them with genetically engineered mammals that are even better at eating grass and rapidly depopulating these former forests of insects, and/or leave AI agents to oversee and ensure that the area remains a wasteland.
Any supporter of practical pro-natalism, who is not willing to bite the bullet on practical non-veganism, must demonstrate that there are cheaper ways to destroy rainforests than buying flesh, and that such alternatives are not available to replace having children.
tl;dr: if you are not a non-vegan due to second order effects of flesh-consumption on wild-animal suffering, you shouldn't be a pro-natalist for those reasons either.
One may argue that even if this is a sufficient reason to not have children ourselves, the environmental effects of having a larger population in general should still at least be taken as a reason to not discourage others from having children, or even to encourage them. But this objection is also applicable to veganism: if purchasing certain types of flesh reduces wild-animal suffering, then one may also argue that there is then no reason to discourage others from doing or so, or that it should even be encouraged.