Remove everything that is not truth. ACIM uses reason as synonymous with the Holy Spirit. The ego's premises are false. Follow out the Holy Spirit's premises to the truth. Learn to not put your faith in the laws of the world, the ego's thought system. Put your faith in the Holy Spirit.
The question of Reason vs faith sometimes comes up. True Spirituality sees reason as divine logic. It is logical to accept that the Spirit cares for you. Faith is Trust in this and therefore we do not need to follow the ways of the world. Nothing of this world will ever satisfy. That is reason. Put your faith in what is true.