THETA-MEST THEORY, 1. a theory generated by myself in the fall of 1950 as an effort to explain (just a theory) the phenomena of an analyzer working in one direction and a reactive mind working in quite another, the reactive mind being interesting, and the analyzer being interested. (5410CM06) 2. the idea is that life is a no-substance thing, up against a physical universe which is a substance thing. Here is nothingness up against a somethingness interacting where the nothingness or the no-substance thing is actually giving orders to and handling the all substance thing, the physical universe. (UPC 3 5406CM––) 3. the idea that there was a universe and that there was thought–theta without wave-length, without mass, without time, without position in space: this was life. And that was impinged upon something else called the physical universe, which was a mechanical entity which did things in a peculiar way, and these two things together, theta-mest interacting, gave us life forms. (PXL, p. 140)
Hubbard, L. R., (1975) Dianetics and Scientology Technical Dictionary. Los Angeles: Church of Scientology of California Publications Organization.