When looking at the morality or desirability of abortions, many claim “if my sibling with X-serious-disability were aborted, then they wouldn’t be alive today with their net-positive life and I wouldn’t know them.” This statement is true and is evidence against the desirability of abortion, but what I have never heard from a pro-lifer is the moral weight of the counterfactual people that could have been born should an abortion have taken place. This is an extremely important factor in deciding the desirability of abortion, and in population ethics in general.
The valuation of counterfactual people is the same as that of potential people which is very similar to the valuation of future people. It is based on some subjective expected-utility of the nature of the person’s subjective experience, the person’s expected net-impact on ethically relevant phenomena, and the probability of them coming into existence, minus a cost function. For counterfactual people, that cost-function is the moral weight of a person who could exist otherwise. This may seem like a tautological definition, but let’s look at a though experiment to more explicitly highlight the need to look at counterfactual people:
“Suppose it was a phenomenon of nature that every women’s first embryo implanted in their womb was destined to live a life barely worth living and would be expected to only barely give back more to society than the societal resources used to raise it. A woman could raise this child to term and get pregnant with a typical child several months after that, or she could have an abortion and end the pregnancy within a couple weeks of it starting, and then get pregnant with a typical child, with much greater expected well-being and societal impact, within a month or two of that. The latter choice, if rationally taken, would require considering marginal cost– that is, the weight of counterfactual people.” I think it’s clear that society would be worse off if we didn’t make the latter choice at least a majority of the time.
Considering marginal cost between having different children doesn’t mean that we must be harsh to our children with less expected impact on society and less well-being. It’s just as morally relevant to be kind to people that could be affected by our words and actions. However, let’s not pretend we are angels when we do a good and ignore the counterfactual better good that could have taken place.