> Famous in the history of science is the (argument _ad_ignorantiam)
> given in criticism of Galileo, when he showed leading astronomers of
> his time the mountains and valleys on the moon that could be seen
> through his telescope. Some scholars of that age, absolutely convinced
> that the moon was a perfect sphere, as theology and Aristotelian
> science had long taught, argued against Galileo that, although we see
> what appear to be mountains and valleys, the moon is in fact a perfect
> sphere, because all its apparent irregularities are filled in by an
> invisible crystalline substance. And this hypothesis, which saves the
> perfection of the heavenly bodies, Galileo could not prove false!