Model predicts we're the only advanced civilization in the observable universe
So, I read this paper and was pretty unconvinced. I think the premise of using a Monte Carlo analysis is flawed because <i>of course</i> multiplying together wide ~iid distributions that have big near-zero components asymptotes to zero; unless I'm misunderstanding something, this is essentially the central limit theorem. (All of the parameter samples below 1e0 drag the total outcome towards zero since probabilities are bounded >= 0)  Thus, the real information is still strongly dominated by beliefs about the width and centering of the distributions, which we still don't know, and as long as enough of the parameters have high uncertainty with some potentially having near-zero values, the result will always tend towards zero.<p>I think what this analysis tell us is that if you don't think it's possible to get better, more specific values for the parameters, the Drake Equation is just a bad tool.<p>Also, the Drake Equation doesn't describe the number of alien civilizations, it describes the likely number of civilizations. Thus, extremely pessimistic estimates have to somehow correct for the fact that we know N is not zero, since we are here. That seems like a highly informative update that is not addressed in an interesting way.