Well, all depends on what you consider 'a fact'. There's only one science that's 100 % exact and non-relative, and that's mathematics. All other sciences are relative to some degree. Like physics, e.g. gravity can differ from one planet to another. Only the rules of math are 100 % exact. So what's a fact? Most consider evolution theory a fact because it has been proven with a lot of evidence. I don't see any reason to doubt evolution theory, because of all the evidence pointing in that way, and no evidence against it.

But who knows

We're now learning that Einstein's theory of relativity might be 'relative' instead of certain as we thought. The theory is based on the premise that nothing can travel faster than light. But some scientists with too much time on their hands and a lof of money discovered it might be possible. ->

http://www.dailytech.com/CERN+Physicist ... e22827.htm

(The results were not within the margin of error)


And about philosophy being useless, well...
Try asking any scientist how useless 'Critique of pure reason' by Immanuel Kant (a philosopher) is. You'll have your answer right there.

Note: don't try reading those books(Critique of pure reason), it will make you crazy in the coconut.