"Atheism: A personal relationship with reality."

[tama]

142. Atheists

as category have nothing to do with the issue discussed, as atheists can have various world views and philosophical positions. The answer you refer to was to cleanhippie, not to atheists in general, AFAIK.

And no, we don't "know" that black holes "exist", except as objects of thought. Yes, based on certain empirical theories "black holes" have been deduced and "predicted", and it is possible that some empirical indirect observations so far support those predictions. But as a whole, the theorizing around and about black holes is almost purely speculative, especially in absence of theory of quantum gravity. Which does not mean it's worthless, as black hole -thought experiments are one way of thinking about quantum gravity and searching unified theory.

Edit: on second thought, it would seem in not in response to cleanhippie but to the bilboard text and humblebums interpretation of that. But the point remains, the text can be interpreted in many ways without assuming that any interpretations would be universally shared by all who identify as atheists.