I've edited this essay to respond and incorporate points made by commenters. Thanks to all who have provided feedback.
This is something I see come up in EA social media spaces and I am keen to state an argument against anti-natalism in clear, strong, and persuasive terms. Typically the anti-natalist case is presented as a way to avoid a significant impact on the climate. I think this is flawed: while the average human certainly has net-negative impact on the climate, the average human also has a net-positive impact on total human well-being, simply by existing and leading a net-positive life.
First, let's survey some morally relevant areas that you have control over, and that having children could impact.
My well-being and yours, and your potential children, all have moral worth. We matter too. If your altruism completely excludes your own well-being, I would be concerned about how sustainable it is. See further notes at the bottom.
Your children matter
Assuming your potential children live average lives, they'll probably experience a lot more happiness than suffering and their lives will be well worth living. The impact that each individual has on the climate is dwarfed by the well-being that person experiences in their own life. These are contestable claims: there are lively arguments over the "total view" vs. the "average view", but I take a total view on this. If you take the average view, you might disagree you should take your potential childrens' well-being into account.
Your own impact on EA matters
Having children will influence your own impact within your career and life on the world. For instance, someone in a particularly impactful career might avoid having children if they think it would lead them to sacrifice making a difference in their career.
If you want to maximize total aggregate happiness in your decision,
- your primary concern should be yourself and your potential co-parent's happiness because that will be massively influenced by your decision - potentially either way, depending on your preferences. Managing own happiness and well-being is an important part of maximizing total aggregate well-being. Therefore, if you don't want to have kids, don't have kids - you don't need climate change to justify that decision!
- Then, as a distant second you should consider the net positive impact your children would experience through living their own lives.
- As an even more distant third priority, think about the impact that having kids would have on your own ability to have an effective career. Now, this may be a persuasive argument against having children for some people. For others, including those earning to give, or people who would simply be less happy not having children, having children might function as a positive motivator that enables you to have a more effective career than you would otherwise.
- In terms of maximizing total well-being, your kids' impact in the climate is a distant fourth relative to all those other concerns I've raised. The magnitude of their impact on the climate is likely to be much, much smaller than any of the three other factors I have raised.
"Is it really true that "effective altruists" should consider their own well-being, too?"
It is true that "altruism" excludes your own well-being by definition. However, a moral system that arbitrarily excludes the agent's own well-being seems arbitrarily selective. Certainly any consequentialist or utilitarian would want to weight their own well-being equally with others.
But this is not just a consequentialist approach. Wider philosophical and religious discourse around morality are also premised on concern for self. The religious command is "Love thy neighbour as thyself", not "Love only thy neighbour, not thyself". Kant's deontological rule is "act only according to that maxim you would have as a universal rule", not "act only according to maxims that would benefit others".
How do we know the negative impact of a marginal individual on climate change is smaller than the positive impact an individual has on their own well-being?
My initial thinking: most of the negative utility of climate change is related to its negative impact on human life. It makes human life somewhat less enjoyable. At its worst, the negative utility of climate change could end all human existence. So there is a scenario in which the negative utility of climate change is equal to the positive summed utility of human existence. However, this scenario is highly unlikely: <1%, and possibly <0.1% (Ord, 2020). So we should strongly downweight the negative utility of climate change.
That said, I think what I've missed here is that the negative utility of human extinction doesn't just cancel out the positive utility of everyone existing now; it is worth the positive utility of everyone who might exist in the future billions of years. So this is part of my argument I might need to reconsider. I'll try to consider this further.