what does it do is as valid as what is it. I do not see the problem here.  And when it comes to describing the nature of reality and the universe, science is the best we've got.  If anyone has any better methods they should propose them and include a proof for their claims to be peer reviewed and published in a journal! When it comes to things that require explaining beyond what science can provide, I assume we're talking about Ethics.  This is not necessarily personal or popular expedience, but there is a lot to be said for the way societies develop rules and morals that benefit their overall well-being.  One might call it evolutionary.