It seems to be ok to be trying to save the world if, as Nate contends, if it takes the one in a million to save the World, there better be a million people trying.

I agree with the commenters who mentioned that we live in a high leverage time (though I think donating to MIRI should not be the main example of future expected returns, since other people may do equivalent research on a third of the MIRI employee cost).

A similar argument can be made for money making and anti-aging for some people. I read a lot of the papers on happiness and money, and I have no doubt I can continue to have a very happy life on a small salary for american standards. But if you put "not dying" into play, it seems worthwhile to actually maximize, or near maximize money and resources, to make sure I have enough resources to not die when anti-aging becomes fungible with money. It feels like an all or nothing.