Full Idea
When faced with an error-possibility we can appeal to background knowledge, as long as the error-possibility does not call into question this background knowledge. The same is not true when we focus on the radical sceptical hypothesis.
Gist of Idea
We assess error against background knowledge, but that is just what radical scepticism challenges
Source
Duncan Pritchard (Epistemological Disjunctivism [2012], 2.§5)
Book Reference
Pritchard,Duncan: 'Epistemological Disjunctivism' [OUP 2012], p.85
A Reaction
[reworded] Doubting everything simultaneously just looks like a mad project. If you doubt linguistic meaning, you can't even express your doubts.