He doubted the validity of induction long before its best known critic David Hume, and raised the regress argument against all forms of reasoning: Those who claim for themselves to judge the truth are bound to possess a criterion of truth.
Han tvivlede på validiteten af induktion længe før dens mest kendte kritiker David Hume, og skabte regresargumentet imod alle former for argumentation: Those who claim for themselves to judge the truth are bound to possess a criterion of truth.