How do you "disclaim" reality?
I don't. And I don't claim to be better informed than Reagan's own economic advisors, I leave that to various pundits who never bother to source their claims. I simply read all the books I could find written by Reagan's economists, and they make the point themselves in their writing. Martin Anderson, William Niskanen, Paul Craig Roberts, Larry Lindsey. Each one wrote a book on the subject. You'll need to ask them why they "disclaim reality". Your source is...?