Actually, no. Or if they do -- they have things a bit askew if they think they "know" that a theory (no matter how valid --or not) is a "fact".
Facts never grow up into being theory. Theories come about as methodology of explanation for observable fact.
During the process of forming theory, one should be aware of, and keep close track of assumptions, and the basis for having made the assumptions. Or else it is or becomes loose "science", with theorizing mistaken for being "fact", such as you have done, grammatically.
Please take careful notice that here I have not ventured anywhere beyond word usage. Yet the words we chose to describe a thing are important, for words, their definitions and usage form our thoughts, becoming basis for opinion.
That reminds me of some relevant gibberish from Bertrand Russell ...
"Don't be so sure - nobody can be certain of anything."