TITLE: Does $A \lor \neg A$ assert decidability in intuitionistic logic?
QUESTION [5 upvotes]: I'm new to intuitionistic logic, so forgive my silly question.
In intuitionistic logic, does $A \lor \neg A$ assert the decidability of $A$? For example, let's say I don't personally have a proof of $A$, but I know someone who has either a proof or a refutation of $A$, but I don't know which one. Can I say in that case that $A \lor \neg A$ is true?

REPLY [2 votes]: In model theoretic view we say we know $A\vee B$ for some sentence $A \vee B$ if we know $A$ or we know $B$, therefore if you want to prove $A \vee \neg A$ for some sentence $A$ then you should prove $A$ or prove $\neg A$ and this leads to decidability of $A$.