Mind is the faculty by which reality undergoes cognition and perception. Langan contends that mind and reality are linked in mutual dependence at the most basic level of understanding. The CTMU is essentially a theory of this relationship. In particular, the CTMU is a theory of reality as mind.
In explaining this relationship, the CTMU shows that reality possesses a complex property akin to self-awareness. That is, just as the mind is real, reality is in some respects like a mind. But when we attempt to answer the obvious question "whose mind?", the answer turns out to be a mathematical and scientific definition of God. This implies that we all exist in what can be called "the Mind of God", and that our individual minds are parts of God's Mind.
The Mind Equals Reality Principle, or M=R, is one of the three metalogical axioms of the CTMU.