A theory is tentative and malleable. A theory is intended to be a reflection of the evidence it attempts to explain, and as more and more evidence is gathered the theory is modified to accommodate it.
All well and good. However, while discussing tentativeness we should not forget that the degree of tentativeness goes down as more and more evidence is accumlated.
After a time the theory becomes so very accepted that the layman's termed like "truth" and "proven" are close enough to the actual view held by the experts in the field.
There is a wide range of confidence in various scientific models. Some are held with a very, very high degeree of confidence indeed. the ToE is one of those.
We have also neglected to point out to Cosmo that aside from the issues about
how evolution happened (the theory part) the
fact that it has happened is still there.
We each choose to accept somethings as being a 'good enough' bet as being correct. The level of 'good enough' varies with the individual and the particular case. Almost all those who know anything at all about the facts of the matter would say that betting on the ToE is very, very good bet indeed.