Re:A Primer on the Doomsday Argument
by saalweachter on Monday August 18, 2014 @02:17PM
(#8193759)
The big gaping hole I see is that the blog post at least doesn't treat the earlier epochs with the same question. If a person in 1000 CE took up the same question, would they predict Doom Early or Doom Late? If everyone for the last ten thousand years would predict Doom Early, that seems like a piss poor predictor.
[ Parent
| on HN ]
Re:A Primer on the Doomsday Argument
by AlexMennen on Monday August 18, 2014 @02:44PM
(#8193892)
That's just a special case of a general feature of probabilistic arguments: a small but positive fraction of the times they are used, they will give wildly misleading predictions. If we assume that everyone uses the doomsday argument with a uniform improper prior on the total number of people who will ever live, then all of them will conclude with 95% probability that they are not one of the first 5% of people to ever live (that is, that no more than 20 times the past population will be created in the future), and 5% of them will be wrong, which is exactly how probabilities are supposed to work.