"Radical skepticism or radical scepticism is the philosophical position that knowledge is most likely impossible.[1] Radical skeptics hold that doubt exists as to the veracity of every belief and that certainty is therefore never justified. To determine the extent to which it is possible to respond to radical skeptical challenges is the task of epistemology or "the theory of knowledge".[2]
The Ancient Greek philosophers Plato, Cratylus and Pyrrho as well as Roman philosopher Sextus Empiricus are among those who expounded theories of radical skepticism. As radical skepticism can be used as an objection for most or all beliefs, many philosophers have attempted to refute it. For example, Bertrand Russell wrote Skepticism, while logically impeccable, is psychologically impossible, and there is an element of frivolous insincerity in any philosophy which pretends to accept it.[3]"
Radical skepticism - Wikipedia, the free encyclopedia
Buddha neither supports radical skepticism nor any other form of skepticism; his enlightenment/revelation lead him to certainties, so he did not support any form/s of skepticism.