One way you could do this is by defining what kinds of claims would be “relevant” to one another and aggregatable. If X is relevant to Y, then enough instances of X (or any other relevant claims) can outweigh Y. Deaths are relevant to other deaths, and we could (although need not) say that should hold no matter the probability. So multiple 0.3 percentage point differences in the probability of death can be aggregated and outweigh a 100 percentage point difference.
Some serious debilitating conditions could also be relevant to death, too, even if less severe.
On the other hand, ice cream is never relevant to death, so there’s no trade off between them. Headaches (a common example) wouldn’t be relevant to death, either.
But this seems kind of wrong as stated, or at least it needs more nuance.
There’s a kind of sequence argument to worry about here, of increasingly strong claims. Is ice cream relevant to 1 extra second of life lost for an individual? Yes. If ice cream is relevant to n extra seconds of life lost for an individual, it seems unlikely 1 more second on top for the individual will make a difference to its relevance. So by induction, ice cream should be relevant to any number of extra seconds of life lost to an individual.
However, the inductive step could fail (with high probability). Where it could fail seems kind of arbitrary, but we could just have moral uncertainty about that.
Also, there are nonarbitrary (but uncertain) places it could fail for this specific sequence. Some people have important life goals that are basically binary, e.g. getting married. Losing enough years of life will prevent those goals from being fulfilled. So, rather than some cutoff on seconds of life lost or death itself, it could be such preferences that give us cutoffs.
Still, preference stength plausibly comes in many different degrees and many preferences themselves are satisfiable to many different degrees, so we could make another sequence argument over preference strengths or differences in degree of satisfaction.
One way you could do this is by defining what kinds of claims would be “relevant” to one another and aggregatable. If X is relevant to Y, then enough instances of X (or any other relevant claims) can outweigh Y. Deaths are relevant to other deaths, and we could (although need not) say that should hold no matter the probability. So multiple 0.3 percentage point differences in the probability of death can be aggregated and outweigh a 100 percentage point difference.
Some serious debilitating conditions could also be relevant to death, too, even if less severe.
On the other hand, ice cream is never relevant to death, so there’s no trade off between them. Headaches (a common example) wouldn’t be relevant to death, either.
I think this is the idea behind one approach to limited aggregation, specifically Voorhoeve, 2014 (https://doi.org/10.1086/677022).
But this seems kind of wrong as stated, or at least it needs more nuance.
There’s a kind of sequence argument to worry about here, of increasingly strong claims. Is ice cream relevant to 1 extra second of life lost for an individual? Yes. If ice cream is relevant to n extra seconds of life lost for an individual, it seems unlikely 1 more second on top for the individual will make a difference to its relevance. So by induction, ice cream should be relevant to any number of extra seconds of life lost to an individual.
However, the inductive step could fail (with high probability). Where it could fail seems kind of arbitrary, but we could just have moral uncertainty about that.
Also, there are nonarbitrary (but uncertain) places it could fail for this specific sequence. Some people have important life goals that are basically binary, e.g. getting married. Losing enough years of life will prevent those goals from being fulfilled. So, rather than some cutoff on seconds of life lost or death itself, it could be such preferences that give us cutoffs.
Still, preference stength plausibly comes in many different degrees and many preferences themselves are satisfiable to many different degrees, so we could make another sequence argument over preference strengths or differences in degree of satisfaction.