Similar to a Unified theory.

A Unified theory is more a reduction of an idea, a Useful model is a system, process, or mechanism for getting a desired result.

Logic, type theory, category theory, functional programming, and Bayesian thinking may all be connectable in a grand Unified theory.

slightly mystical enlightenment that comes with expertise, an ability to move through the world fluidly and with your Unified theory of reason and thought.

Can Probabilistic Thinking be a Unified theory for reason and belief updating? It would need to fully subordinate Bayes’ Theorem and Solomonoff Induction (the latter of which may already be a Unified theory of its own).

Unified theory isomorphism -> A unified language

When a new clarity of thought is achieved, it opens up potential new progress. This is similar to creating a Unified theory of thought, and also to creating a unifying language A unifying language enables further discovery.

Sometimes a Unified theory can be a useful model, but not always.