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Comment by seppel | Hacker News Reader

> However, the result is extremely different if, rather than using point estimates, we take account of our uncertainty in the parameters by treating each parameter as if it were uniformly drawn from the interval [0, 0.2]. Monte Carlo simulation shows that this actually produces an empty galaxy 21.45 % of the time.

Isn't that just elaborated way of saying that some of the parameters of the Drake equation have to be much smaller than we think?

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Yeah - but they don't have to be much smaller.

Let's use the simple example you reference from the paper. If we just use the mean as point estimates, then indeed we obtain an extremely low probability that there's no other intelligences:

  def prob_of_no_intelligence_in_galaxy(p):
      prob_of_intelligence = pow(p, 9)
      planets = 100e9
      return pow(1-prob_of_intelligence, planets)

  prob_of_no_intelligence_in_galaxy(0.1) -> 3.720086311124783e-44

However, there is already a 82% chance of an empty galaxy if the parameter p is halved:

  prob_of_no_intelligence_in_galaxy(0.05) -> 0.8225792614407508

Now of course halving every probability is a lot, however now there's no single or few events that have a very low probability of happening. The Great Filter disappears.

See also my other comment here: https://news.ycombinator.com/item?id=25811359

Why do you have 9 factors? The classical Drake equation has 6 (and the L which is the avg. lifetime of the civilization).

Also: The Drake equation has one factor which is the avg number of planets per star, of which we are already quite confident it is above 0.1.

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