So how do we stop him? We can learn something from what Mises wrote in Human Action. He says that a person will not act unless he thinks he has a chance of accomplishing what he sets out to do. If he thinks it's hopeless, he won't even try. Like the guy in the bookstore flipping through a book on optimism, then not buying it because "what's the use?"
So there's our first step, knowing the battle can be won. We can't change all the crummy things that happen, or the dumb things we did in the past, but we can stop our Inner Critic from saying it is all our fault, that we will never do anything right, and the like.
How do we know it can be done? From other peoples experience. Dr Rubin writes, based on decades of working with people, that Mr Hyde is like a house of cards that can be blown away [eventually], and like a salami that can be gotten rid of slice by slice. So it can be done.