AchrisK
Weakling
You might for instance look at the fact that Einstein's theory of general relativity is currently incompatible with the laws of quantum mechanics. All attempts at creating a unified theory have been unsuccessful so far, yet both theories hold up to empirical evidence and are considered facts. Something can be known to be incomplete and yet still be true based on what we currently know.
http://en.wikipedia.org/wiki/Unified_Field_Theory
This is interesting, but I don't know that it applies as a precident for what science defines as fact (which is the point about evolution that I am questioning). It seems like this article is saying they haven't been able to find a single theory that can bring Strong nuclear force, Electromagnetic force, Weak nuclear force and Gravitational force together into a single framework that can be used to describe and predict for all four force-mediating fields. This doesn't seem to question the facthood of any single theory. It may be that they are too different from each other in ways that make a single unifying theory unrealistic, or maybe one day they will find a correlation that will allow a single unifying theory.