Nice post Mr. Tegmark, ty! Regarding your statement
"...(80%) that NATO's response will be forceful enough to include a non-nuclear military strike against Russia, because key NATO leaders have already made strongly worded statements to this effect"
would you (or can anyone else?) kindly supply direct quotes (please not merely citations of news articles that paraphrase or that quote less than complete sentences) of some such statements? For the ones not cited or quoted, maybe Mr. Tegmark will clarify whether he means key current NATO officials or merely key current officials of NATO member countries, or whether perhaps retired former officials is what was instead meant? Fwiw the reason for my request, besides the obvious one that the claim is a key one in the analysis, is that the only people from whom I've read the claimed statements are current couch-sitters and not even "NATO leader" ones. At most they are former nonmilitary govt officials. Have retired generals such as Hodges or Hertling said NATO direct military response is highly likely? If the only such opinions that could be found were of this "armchair" variety, I'd say they'd give some grounding to Mr. Tegmark's remarkably high "80%" estimate. (So far I see a quote from Hodges that characterizes his probability estimate as US "could well" do this or that direct military action", which is laughably different to the "WILL" (no kidding, all-caps) stated in the headline of the newspaper article in which the actual quote is sort of eventually dribbled out.)
Edited to add: [Here's a retired general] (https://mobile.twitter.com/mccaffreyr3/status/1568769530658435072) whose probability estimate seems to go a bit higher than Hodges' "could well...". I'm really starting to think that such couch surfers (no offense to couch surfers) are actually who Mr. Tegmark rather slyly means by "key NATO leaders" but if he did mean actual NATO officials then I'd consider that to be a huge difference.
In a few places you compare, from a person's perspective, the "fortune" of that person (or what "seems positive for" them), to their fortune if they never existed. How can this mean anything? I don't think that someone/something that (hypothetically) doesn't exist can have a (hypothetical) perspective. (And if they can't even have a perspective, it probably doesn't need to be said that neither can they have a fortune to compare to a fortune arising from a perspective on a (real or hypothetical) existence.
Seems more sensible (and might possibly make a practical difference) to, instead, judge from the perspective of those affected by the person in question. For example, instead of saying "Fortunately for my friend, the priest said yes", saying "Fortunately for me, the priest said yes."