Ignorance is bliss (statistically speaking)

Which is why there must be giraffes on the planets orbiting Alpha Centauri.

At a seminar with his colleagues, Hugo Wellie claims that there are breeds of dog on one of the planets orbiting Sirius. Naturally, one of his colleagues asks how that can be and he counters with the question whether there’s life on Mars or the moons of Jupiter. It seems probable that there is, but as Hugo notes, if there is life, it’s probably just bacteria. The discovery of more complex creatures is highly unlikely. But our man thinks that if the chance of finding complex lifeforms in the solar system is highly unlikely, then it’s highly likely that they will be found on one of the planets orbiting Sirius.

OK, Hugo, dazzle me with your genius.

The Principle of Insufficient Reason. If we have no information about something, there’s a 50-50 chance that it is or is not. (It’s like yesterday’s problem, it would seem – heads vs. tails; true vs. false; yes vs. no; black vs. white; day vs. … [I think we’ve got the idea. –ed.]) (I’m sceptical because whether something is or is not, I’m still speculating either way; by Hugo’s reasoning, what he thinks is highly likely is just as equally unlikely unless, of course, my reasoning is flawed; the reason for his confidence that something is is just as good a reason for someone else’s confidence that it isn’t; are we getting into Hume’s is-is-not-ought territory?)

Hugo’s subsequent analogy based on coin tossing would seem to be flawed as Louie’s reasoning was flawed yesterday. Even if a coin were to be heads five hundred times in a row, there’s still only a 50-50 chance that it’ll be tails on each occasion. The chance of tails doesn’t increase just because the coin comes up heads n times. But he seems to be using such a reason to claim that there are dogs on some planet orbiting Sirius.

The discussion in the book is about strange coincidences which are, unsurprisingly, statistically unlikely such as the father and daughter who were both killed on a level crossing at the same time by the same train driven by the same driver, but four years apart; or the fortuitous wrong number which saved someone during the war; or the superstitious who have been saved because some chance event had deterred them from travelling on a plane which then crashes.

I still think Hugo’s reasoning is flawed by being based on idle speculation and because he overlooks the possibility that the same arguments seem just as applicable to a state of non-being.

We’re staying in an infinite hotel tomorrow; or perhaps one that’s even more infinite. Pack your suitcases; we might be in for a long stay.

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