In rudimentary logic those to thoughts cannot co-exist. If I drop a ball, it falls to the ground EVERY time. It is a fact and the term used for that manifestation is gravity. No one disputes that fact. What we are lacking in the "theory of evolution" is a reproducible "fact" to place it in the same category as gravity.
My daughter takes "Music Theory" in college. It always confused me why they called it "Music Theory" until I got into this Evolution discussion. Like Evolution, Music in fact exists. But the study of it, the description of the process of making music or of evolving a species is called it's "theory".
Here you go: http://www.thermionics.com/ip_too.htm (don't know how to post real link). That's the "Theory of Operation for Ion Pumps". They often publish Theory of operation for computer processors too. Ion pumps and computer processors exist in FACT, and their operation is their THEORY.
To describe how the FACT of Evolution works, you write a "Theory of Evolution".