I imagine that's true sometimes. On the other hand, hypothetically, if it were the case that we were missing a key definition that's needed for some proof, and

I imagine that's true sometimes. On the other hand, hypothetically, if it were the case that we were missing a key definition that's needed for some proof, and someone didn't believe that proof, then maybe we would't quite know enough yet to decide that the person is in mental kindergarten. A better first step for us might be to supply the missing definition.