Burton, yeah it’s unclear whether skepticism of kataleptic impressions extends to mathematics, logic, and so forth. Personally, I think it does. Poincaré may have *thought* he saw the solution to the problem, but the solution might have been wrong.

The concept of kataleptic impression is subtle: the Skeptics are not saying that there are no true impressions, only that there is no clear mark that separates the true ones from the false ones.

As for Descartes, yeah, invoking god as a guarantor was a pretty bad cop out, resulting in what some philosophers refer to as Descartes’s vicious circle.