I just recently (finally) read this paper thanks to @GnomeGodsGnomeMasters@hexbear.net and as much as it’s a really interesting framework, imo it has serious problems particularly with the Weak Harming Principle B it asserts and I’m curious to hear what anyone here thinks.

If you don’t want to read the 22 page paper (valid, but imo it’s worth it), I’ll summarize the relevant bits below. ::: spoiler TLDR/glossary of the relevant parts:

Harm vs interest: you have an interest in something positive, and are harmed by that being taken from you. Also, you can be harmed by things, and have an interest in that not happening
Trivial harm/interest: something minor to a being, ex getting/not getting a cupcake
Serious harm/interest: something relevant to your ability to enjoy life, like meaningful projects/relationships, species-natural behaviour, loss of limbs
Basic harm/interest: something necessary for your ability to enjoy life, like not being killed or held captive forever in a tiny cell

Weak harming principle A: We ought to cause trivial harm to (an) individual(s) when doing so is necessary to prevent a serious (basic or non-basic) harm to (an)other(s).
Weak harming principle B: We ought to cause non-basic harm to (an) individual(s) when doing so is necessary to prevent a basic harm to (an)other(s).
Strong harming principle: We ought not to treat the basic harm of one as equal to or greater than the basic harms of two or more individuals. :::

The problem I have is best shown on page 21-22, where the author says:

Essentially, there are both bad and good reasons for harming. The rights view holds that a wrong reason for harming animals is this: harming will bring about “the best” aggregate consequences for all those affected by the outcome. And, as argued, two acceptable justifications for causing harm are: (1) the harm is non-basic and causing it will prevent another from enduring a basic harm, or (2) the harm is trivial and causing it will prevent another from enduring a serious harm. While we should not appeal to the aggregate of harm to justify harm imposition, we ought to appeal to the magnitude of harm (Regan 1983, 389–390).

They explicitly argue we shouldn’t look at the total harm caused, and instead look only at the magnitude on each recipient, but this plus the Weak Harming Principle B implies some pretty wild shit.
The Weak Harming Principle B alone implies that if it’s necessary to cut off one person’s arms to save another person’s life, we should do it. Under the constraints that the second person’s life ending is a basic harm (they have a life worth living, they wouldn’t die the next day anyway, etc) I think this is a reasonable view even if I’m not sure I agree personally. Pairing this with the “look at the magnitude of harm, not the aggregate” leads to the mildly insane conclusion that if it’s necessary to save that one person’s life, we should cut off every pair of arms on earth.
This isn’t me cherry picking the author for one badly phrased sentence or anything, either - they very explicitly establish that (basic harm of one being) > (serious harm of many beings) more than once throughout the essay, though with significantly less extreme examples than I used.

This framework feels really promising to me, other than this (significant imo) hole in it - it seems like the bones of it are correct but it needs another piece or two to be complete. Does anyone have any ideas about what those pieces might be? Am I just missing something in my understanding? I’d appreciate any thoughts