Metamath Proof Explorer

Theorem curryax

Description: A non-intuitionistic positive statement, sometimes called a paradox of material implication. Sometimes called Curry's axiom. Similar to exmid (obtained by substituting F. for ps ) but positive. For another non-intuitionistic positive statement, see peirce . (Contributed by BJ, 4-Apr-2021)

Ref Expression
Assertion curryax φ φ ψ


Step Hyp Ref Expression
1 pm2.21 ¬ φ φ ψ
2 1 orri φ φ ψ