That's not precisely correct though. I could say that the dog ate food at any time, however, though would be a hypothesis as I have no evidence what so ever to prove it right. If I say that the dog ate food and we find the dog's hair on the plate, I have a theory. I have evidence of the dog's presence at the crime scene and no reference to the cat at all. Of course this doesn't mean that we have absolute certainty in that assumption, but it is by far more plausible then the reference to the cat.

As far as the evolution goes, we have evidence of the bones of the beings being there that resemble humans. We have the data on the age of different fossils, which allows us linking them together and thus getting the popular "evolution of man" picture. We have retroviruses that -evolve- in the hospitals, thus proving that evolution can take place.

At this point we are certain that evolution in general takes place right now. We have very strong reasons to assume that it took place in humans. And we have no evidence or theories of Creation at all, save a couple of old far fetched and improvable hypothesises that build our culture. All else is irrelevant.