My point is that “If you can’t add, how can you average?” is not a valid argument, even though in this particular case both the premise and the conclusion happen to be correct.
If I ask “If you can’t add, how can you average?” and TimFreeman responds with “by using utilities that live in affine spaces,” I then respond with “great, those utilities are useless for doing what you want to do.” When a rhetorical question has an answer, the answer needs to be material to invalidate its rhetorical function; where’s the invalidity?
I took the rhetorical question to implicitly be the syllogism ‘you can’t sum different people’s utilities, you can’t average what you can’ t sum, therefore you can’ average different people’s utilities’. I just pointed out that the second premise isn’t generally true. (Both the first premise and the conclusion are true, which is why it’s a nitpick.) Did I over-interpret the rhetorical question?
The direction I took the rhetorical question was “utilities aren’t numbers, they’re mappings,” which does not require the second premise. I agree with you that the syllogism you presented is flawed.
If I ask “If you can’t add, how can you average?” and TimFreeman responds with “by using utilities that live in affine spaces,” I then respond with “great, those utilities are useless for doing what you want to do.” When a rhetorical question has an answer, the answer needs to be material to invalidate its rhetorical function; where’s the invalidity?
I took the rhetorical question to implicitly be the syllogism ‘you can’t sum different people’s utilities, you can’t average what you can’ t sum, therefore you can’ average different people’s utilities’. I just pointed out that the second premise isn’t generally true. (Both the first premise and the conclusion are true, which is why it’s a nitpick.) Did I over-interpret the rhetorical question?
The direction I took the rhetorical question was “utilities aren’t numbers, they’re mappings,” which does not require the second premise. I agree with you that the syllogism you presented is flawed.