Science is tentative, including scientific "fact." It was a fact that the earth was flat and it was also a fact that the earth is round. Obviously, only one or none could be right. It was once a fact that caffeine was neutral. Then it was a fact that caffeine is terrible for you. Now its a fact that it has legitimate medicinal purposes. Do you understand what I'm saying? And, yes, its great that science can keep evolving in order to uncover the truth, whatever it may be, but this "truth" or "fact" may be supplanted the following year, which makes people leery of committing to anything.
I don't mean to burst your bubble but the earth was never flat. Also, I'm certian it won't be flat tomorrow.
Science can reach conclusions that to all intents and purposes are irrefutable. It is not a matter of 'tentative opinion' that a solid lead ball thrown into the air will return to earth.