In the CTMU, reality is the most inclusive domain. By definition, there is nothing outside reality. This means that reality is self-contained. Everything real enough to affect reality is inside it. Langan calls this the Reality Principle: reality contains all and only that which is real. The idea that reality is self-contained is the kernel of the CTMU, the seed from which the rest of the theory is built.
Langan refines the definition of reality as follows.
Reality is the perceptual aggregate including (1) all scientific observations that ever were and ever will be, and (2) the entire abstract and/or cognitive explanatory infrastructure of perception.
That is, reality consists of (1) perceptions, and (2) all relevant supporting structure. For example, if you see an apple fall from a tree, your perception of the apple qualifies as real by (1), while the law of gravity that caused the apple to fall qualifies as real by (2).
Langan uses "nature", "existence", and "the real universe" as synonyms for "reality". Since reality is the most inclusive domain, a general theory of reality would be a Theory of Everything. The CTMU is intended to be such a theory.
The CTMU characterizes reality as a Self-Configuring Self-Processing Language (SCSPL).
- Langan 2002, p. 16.