From Ian Wilson, University of Reading
Gott’s calculation suggests that a 39-year-old man has a 95 per cent
probability of living between 39/39 years (= one year) and 39 x 39 years (= 1521
years), but his baby child aged 0.39 years has a 95 per cent probability of
living one-hundredth as long, between 0.01 and 15.21 years. Of course we know a
great deal about the spread of human survival times so it’s clear this is
nonsense.
Gott implicitly assumes a very different distribution of potential survival
times, and its general applicability. The argument would get a bit more
interesting if that were explicit and its plausibility discussed with a serious
eye to the evidence. Meantime, I’d vote not to pay for the colonisation of Mars
on the basis of half a probability argument.
