The same basic principle can be applied to reason. In discussions and debates, the immovable point is that point at which the two parties agree. For instance, if I wanted to discuss morality with someone, it is necessary to find the point at which the other person and I disagree. If we both agree that God exists, then that is an immovable point at which we could begin our discussion. The fact that it is often hard to find an immovable point explains why discussing current moral dilemmas can be so frustrating.
Many people believe that there is no such thing as a universal right and wrong.
From this point, no progress can be made in moral philosophy, and issues like abortion or homosexuality cannot be discussed in any reasonable manner.