[oolonthegreat]

> The idea that fluid is solving the Navier-Stokes equation seems like an obvious error to me - it cannot solve the equation, it simply acts a fluid, which the equation was designed to approximate.

that's his "Principle of Computational Equivalence", that natural processes are themselves computations. it's easy to see this is true in a "made-up" universe, say Game of Life, but whether our universe is computational is still an open question I think.