Just like Global warming
tested hypotheses and theories are two different things. Just FYI.
Yes it is theory, but very well supported theory, unlike global warming. All non-experimental geology is theory based on circumstantial evidence. The evidence is heavily in favor of plate tectonic theory.
Are you a geosynclinalist?
THEORY.....
Just like Gravity
A theory based on past history as opposed to theory based on supposition. Not the same thing. These guys have actually taken known facts and observations and plugged them into the computers to come up with their theory. The GW crowd goes the opposite direction. They have the answer, i.e. the computer models and now are trying to find proof.
As is everything in science. The thing is, this one postulates a cause or mechanism, rather than just being description. It apparently does a better job of explaining the observations than the "bottoms up" theory.
E=MC^2 is "just a theory" too. But don't stand too close to the devices that exhibit the "theory".