It’s perfectly correct that your estimate of P(cryonics will work for me) should go down as you think of more things that all have to happen for it to work. When something depends on many things all working right, it’s less likely to work out than intuition suggests; that’s one reason why project time estimates are almost always much too short, and why many projects fail.
Of course my probability estimates are only rough guesses. I don’t trust estimates derived in this way very much; but I trust an estimate derived by breaking the problem down into smallish bits and handwaving all the bits better than I trust one derived by handwaving the whole thing. (And there’s nothing about the breaking-it-down approach that necessitates a pessimistic answer; Robin Hanson did a similar handwavy calculation over on OB a little while ago and came up with a very different result.)
The estimate of 80% for #2 was not mine but Roko’s. My estimate for that one is 25%. I’m not in the US, which I gather makes a substantial difference, but in any case, as your later edit points out, it looks like my number may be better than Roko’s anyway.
Yes, the relationship between all those factors is not as simple as a bunch of independent events. That would be why, in the comment you’re replying to, I said “Suppose (for simplicity) that the probability we seek is the product of several independent probabilities, each of which I have independently estimated.” And also why some of my original estimates were explicitly made conditional on their predecessors.
“Shut up and multiply” was never meant to be taken literally, and as it happens I am not so stupid as to think that because someone once said “Shut up and multiply” I should therefore treat all probability calculations as chains of independent events. “Shut up and calculate” would be more accurate, but in the particular cases for which SUAM was (I think) coined the key calculations were very simple.
It’s perfectly correct that your estimate of P(cryonics will work for me) should go down as you think of more things that all have to happen for it to work. When something depends on many things all working right, it’s less likely to work out than intuition suggests; that’s one reason why project time estimates are almost always much too short, and why many projects fail.
Of course my probability estimates are only rough guesses. I don’t trust estimates derived in this way very much; but I trust an estimate derived by breaking the problem down into smallish bits and handwaving all the bits better than I trust one derived by handwaving the whole thing. (And there’s nothing about the breaking-it-down approach that necessitates a pessimistic answer; Robin Hanson did a similar handwavy calculation over on OB a little while ago and came up with a very different result.)
The estimate of 80% for #2 was not mine but Roko’s. My estimate for that one is 25%. I’m not in the US, which I gather makes a substantial difference, but in any case, as your later edit points out, it looks like my number may be better than Roko’s anyway.
Yes, the relationship between all those factors is not as simple as a bunch of independent events. That would be why, in the comment you’re replying to, I said “Suppose (for simplicity) that the probability we seek is the product of several independent probabilities, each of which I have independently estimated.” And also why some of my original estimates were explicitly made conditional on their predecessors.
“Shut up and multiply” was never meant to be taken literally, and as it happens I am not so stupid as to think that because someone once said “Shut up and multiply” I should therefore treat all probability calculations as chains of independent events. “Shut up and calculate” would be more accurate, but in the particular cases for which SUAM was (I think) coined the key calculations were very simple.