But, Calvin, P(intelligent life contacting us | intelligent life exists) >= P(intelligent life contacting us | intelligent life does not exist) = 0, so the fact that no other intelligent life has contacted us can only be evidence against its existence.
(The problem with formally bringing out Bayes’ law is that, by the time you’ve gone through and stated everything “properly”, your toboggan will have already crashed into the brier patch.)
I think the joke hinges on equivocation of the word “intelligent”. Taboo “intelligent”, use “sapient” and “clever” for the two meanings, and you get: “Sometimes I think the surest sign that clever life exists elsewhere in the universe is that no sapient life has tried to contact us.” Or, put more accurately, “the fact that no sapient life has contacted us is evidence that, if sapient life exists elsewhere in the universe, it’s probably also clever”.
But, Calvin, P(intelligent life contacting us | intelligent life exists) >= P(intelligent life contacting us | intelligent life does not exist) = 0, so the fact that no other intelligent life has contacted us can only be evidence against its existence.
(The problem with formally bringing out Bayes’ law is that, by the time you’ve gone through and stated everything “properly”, your toboggan will have already crashed into the brier patch.)
I think the joke hinges on equivocation of the word “intelligent”. Taboo “intelligent”, use “sapient” and “clever” for the two meanings, and you get: “Sometimes I think the surest sign that clever life exists elsewhere in the universe is that no sapient life has tried to contact us.” Or, put more accurately, “the fact that no sapient life has contacted us is evidence that, if sapient life exists elsewhere in the universe, it’s probably also clever”.