A lack of scientific certainty should never be allowed to undercut our ability (and responsibility) to act on imperfect information. People who think science is certain don't understand science. We only ever have contingent knowledge - the most robust scientific thinking at a given moment - and this thinking is always subject to change. That's what makes it science. But just because the thing is imperfect does not actionable. Newtonian science is not perfect but it's enough to get us to the moon and back.
Mark Jannot - Editor-in-Chief Popular Science February 2012