Theorem curryax 907

Description: A non-intuitionistic positive statement, sometimes called a paradox of material implication. Sometimes called Curry's axiom. Similar to exmid 908 (obtained by substituting ⊥ for 𝜓) but positive. For another non-intuitionistic positive statement, see peirce 205. (Contributed by BJ, 4-Apr-2021.)

Assertion

Ref	Expression
curryax	⊢ (𝜑 ∨ (𝜑 → 𝜓))

Proof of Theorem curryax

Step	Hyp	Ref	Expression
1		pm2.21 124	. 2 ⊢ (¬ 𝜑 → (𝜑 → 𝜓))
2	1	orri 876	1 ⊢ (𝜑 ∨ (𝜑 → 𝜓))

This proof depends on syntax axioms:   → wi 4   ∨ wo 861

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This proof depends on definitions:  df-bi 210  df-or 862

This theorem is used by:  reuprg  4674  tsim2  38821