I guess you're worried that if the same argument works in both cases then you might end up obliged to give Joe $1M.
No, I'm claiming neither Kindly nor you actually believe the argument you've given.
So the simple-minded "do whatever makes people happiest" principle (a.k.a. total utilitarianism, but you don't have to be a total utilitarian for this to be a reason, as opposed to the only possible reason, for doing something) gives the "right" answers in most cases.
Except, you're not doing that, i.e., you're not giving all your income to charity. So since you're willing to ignore parts of your ethics when its inconvenient, why not also ignore the parts about not killing Joe when it would be convenient were Joe to die.
I'm claiming neither Kindly nor you actually believe the argument you've given.
Your overconfidence in your mind-reading abilities is noted.
Except you're not doing that [...]
The fact that someone doesn't act as a perfect utility maximizer doesn't mean that utility gains aren't worth seeking, for them out for others. If you ask "why did you buy that thing?" and I say I bought it because it was half the price of the alternative, am I refuted if you point out that I don't always buy the cheapest things I can?
As I said: a reason, not the only possible reason.
Link to Blog Post: "Extremism in Thought Experiments is No Vice"
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This is a LW discussion post for Yvain's blog posts at Slate Star Codex, as per tog's suggestion:
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