An interrelated system of ideas that is centered on a view of who you are, provides a picture of reality and your relationship with it, and provides goals and how to attain them. You use your thought system to organize your reality. It is the basis for your thoughts, emotions, perceptions and behaviors. There are only two thought systems, the ego's and God's (or the Holy Spirit's, which is a reflection of God's). Each one is internally consistent, yet they are diametrically opposed in foundation, in nature, and in result. You cannot reconcile them by combining them or vacillating between them. You must choose all of one and none of the other. The Course treats its own thought system as a version of the Holy Spirit's and claims its thought system is consistent, complete (see W-pI.42.7:2), cohesive, and includes no fear. See T-11.In.1.