 Intuitionistic propositional logic is weaker than classical propositional logic. All intuitionistically valid formulas are classically valid, but classically valid formulas like \((A \vee \lnot A)\) and \((\lnot \lnot A \rightarrow A)\) are not intuitionistically  valid.[8]  The exclusion of these formulas from the range of intuitionistic theorems can be motivated by the usual Brouwer-Heyting-Kolmogorov interpretation of the connectives: