pete wolfendale (@deontologistics): So, I'm reading MacAskill's 'What We Owe The Future', and though I'll have some more things to say about it at a later date, I have to stop and address what I take to be a truly, characteristically bad argument he makes therein (p. 176-177 for anyone interested).
At this point M is trying to argue against what he calls 'the intuition of neutrality' in population ethics, which is essentially that it is neither better nor worse to bring new people into existence. He has more to say about this intuition, but I'll stick to this one argument.
The argument is as follows: say a couple are considering having a child, but the mother has a vitamin deficiency that will result in a child with migraines if conceived before supplements. They have three options: a) no kid, b) kid w/ migraines now, or c) kid w/o migraines later.
Neutrality implies that options (b) and (c) are both as good as option (a), but that in turn implies that they should be equally as good as one another. This contradicts the obvious moral imperative to choose (c) over (b), all else being equal. So neutrality must be rejected.
Honestly, from my perspective, this is an exceptionally good example of how decision theory can rot one's brain. Choice, and therefore obligations to choose, can only be conceived as selecting between ranked outcomes. All reasoning is flattened into an order relation on states.
The possibility that there might be something as simple as a conditional obligation ('if you choose to have a child, it is better to conceive it so as to avoid having migraines') is simply not considered. The local richness of practical reasoning is dissolved into a global soup.
There is a related problem that happens a little earlier in the chapter, where he tries to turn the intuition of neutrality against the person-affecting views in population ethics that are generally used to justify it. This turns upon the indeterminate identity of future people.
M argues that because identity is extremely counterfactually fragile (slight changes to context of conception result in distinct people being born) and any long term intervention will effect these contexts, neutrality implies that all such interventions are equally worthwhile.
To put this in more concrete terms, if we enact a climate change action plan to make the future better for those who follow us, the people who will exist in the future will be distinct from the people who would have existed otherwise, and so it could not strictly be better.
This is meant to discourage us from person-affecting views on which our moral responsibilities are to determinate people, in favour of the sorts of ethics-as-universe-design views favoured by M, whose quantitative considerations are essentially independent of identity conditions.
But this discounts the possibility of de dicto as opposed to de re obligations: 'We should preserve the environment for [those that come after us]', where the referent of term is taken to vary with possible outcome, rather than be fixed across it.
As I've argued recently, de dicto obligations to whoever happens to exist beyond the scope of our actions are entirely coherent and distinct from obligations to purely notional people whose existence lies entirely within their scope: https://twitter.com/deontologistics/status/1562368776812781568?s=20&t=0bYLFl-w5dSYbdehAAOnnQ
I think this points more generally to a serious equivocation over the place of agency within the book, and the sorts of position it exemplifies, but that's a thought to be developed at another time. 🖖