Ballocks. That's a deduction, not an assumption.
All deductions result in, and are based upon, the assumption they accurately reflect reality. Once one makes a conclusion, he uses it as an assumption upon which to base further thought. And no matter how many times you write to the contrary, a theory by definition entails a set of assumptions. Besides, it is common usage to make use of the word "theory" in a manner that deflects the meaning of "fact" or "absolute truth."