The great German mathematician David Hilbert’s creation, de facto, was—no, is—a theory of everything or world formula, even though he himself had little chance of fully realizing this. Even in physics, where we can now show that Hilbert’s fundamental equation covers both great theories, General Theory of Relativity and Quantum Theory, the time was not ripe for such a discovery, simply because the mathematical apparatus of Quantum Theory was not fully developed then. While Hilbert brought out his great work in 1915 and knew about the Einstein field equations at the time, the basic quantum equations such as the Schrödinger, Klein–Gordon, and Dirac equations would not follow before the second half of the 1920s.
In order to find the mathematical and physical fundament for the description of the body, the soul, and the whole universe, which is to say a "theory of everything," we think that we require "quantum gravity." That such a theory—in principle—already exists and was derived by Hilbert and elaborated in the author’s previous work, The World Formula: A Late Recognition of David Hilbert’s Stroke of Genius. This book digs deeper and shows not only that quantum gravity is more than just a physical theory—describing physical aspects—but also that, in fact, it covers "it all."