“As of now, string theorists have no explanation of why there are three large dimensions as well as time, and the other dimensions are microscopic. Proposals about that have been all over the map.” -Edward Witten
Earlier this month, a conference was held devoted to the question of whether untestable scientific ideas like string theory and the multiverse are actually science or not. While many opinions were stated and no one changed their mind, the answer is apparent: unless you’re willing to change the definition of science to include ‘this thing that isn’t science,’ then no, string theory is not science.
It’s a theory in the sense of a mathematical theory — like set theory, group theory or number theory — but it isn’t yet a scientific theory. Of course, it could become science, but that would require that it actually do the things a scientific theory does: make testable predictions that can be validated or falsified.
That’ll be a day we all greet with great joy. But until then, here’s why string theory is not science.