This seems great, but as I understand it, air purifiers & ventilators also have the benefit of removing air pollution & mold, which as far as I can tell, far-UVC can't? It seems like a relevant thing to mention.

Out of interest: what brand of peanut butter did you eat?

Is there any reason we should trust Omega to be telling the truth in the XOR-trolley problem?

I intended the karmic argument to be implicit in the negative space of the argument on ignoble origins of wealth :) To me it's a matter of course that if you fairly trade with someone, you have moral claim to the wealth thereby earned!

Also, funny: I'm a compatibilist non-moral-realist as well (and inspired by the Hogfather quote, too)! Morality is a social construct, and so is desert, I just find it important to think about the interplay of the two.

Thank you for the kind words :)

I'll give a real-world example for a world ontologically prior to redistributive taxation (and, in fact, most taxation): the US, pre-1900. Minimal taxes were collected (90% of federal government was funded by taxes on tobacco, beer, and liquor) and pretty much none of it went to redistribution. To me, it seems that there was an ideological change somewhere in the early 1900s, driven by the Progressive movement, such that Americans started to approve of redistributive taxation as a concept. 

So basically what I'm saying is that the difference I outlined in my post between public-goods and redistributive taxation is real and that there are moral arguments for and against redistributive taxes as a class (rather than as individual, specific taxes), as indicated by the fact that at first only taxes for public goods like defense were inside the Overton Window, and eventually redistributive taxes became acceptable as well. It's a difference in kind, not degree. This means it is possible to accept some amount of government coercion and yet not be 'negotiating on price' in rejecting forcible redistribution.

ACX also links to this paper analyzing federal cancer research, which claims it is so effective it only costs $326 in federal investment cost per life saved.

They claim $326 per life-year (specifically, DALY), not per life. Huge difference!

I agree with what you're saying; the reason I used trillions was exactly because it's an amount nobody has. Any being which can produce a trillion dollars on the spot is likely (more than 50%, is my guess) powerful enough to produce two trillion dollars, while the same cannot be said for billions.

As for expected utility vs expected payoff, I agree that under conditions of diminishing marginal utility the offer is almost never worth taking. I am perhaps a bit too used to the more absurd versions of Pascal's Mugging, where the mugger promises to grant you utility directly, or disutility in the form of a quadrillion years of torture.

Probably the intuition against accepting the money offer does indeed lie in diminishing marginal utility, but I find it interesting that I'm not tempted to take the offer even if it's stated in terms of things with constant marginal utility to me, like lives saved or years of torture prevented.

For smaller amounts of money (/utility), this works. But think of the scenario where the mugger promises you one trillion $ and you say no, based on the expected value. He then offers you two trillion $ (let's say your marginal utility of money is constant at this level, because you're an effective altruist and expect to save twice as many lives with twice the money). Do you really think that the mugger being willing to give you two trillion is less than half as likely as him being willing to give you one trilion? It seems to me that anyone willing and able to give a stranger one trillion for a bet is probably also able to give twice as much money.