The
Drake equation is filled with wonderfully
well
known numbers, like the probability
for life, then intelligent life to evolve.
Also with quite well known
statistics such
as how many stars have earth-sized planets
with similar enviornments (which we know
very well because the science of planet
formation is understood so well)
No, wait a minute, we don't know any of those
thinks, Doh!. I guess the Drake equation
might just be wrong then eh!