To bypass Lehmann’s theorem against Heisenberg’s “Unified Field Theory of Elementary Particles,” requiring a Hilbert space with an indefinite metric, which is in conflict with the quantum mechanical probability interpretation, it was proposed by the author that Lorentz invariance, on of the fundamental assumptions made by Heisenberg, is a dynamic symmetry, approximately only valid for energies small compared to the Planck energy of ~10^19 GeV, with the fundamental symmetry of nature the Galilei group, in agreement with Mach’s principle. There then Heisenberg’s theory can be reformulated as an exactly non-relativistic quantum field theory with a positive definite metric in Hilbert space. With the Hamiltonian operator in such a theory commuting with the particle number operator, Heisenberg’s ground state of the vacuum is permitted to be a zero temperature plasma made up of positive and negative Planck mass particles which are one Planck mass per Planck length volume, interacting with the Planck force over a Planck length. Making for this Planck mass plasma the Hartree-Foch approximation, one obtains the Landau-Ginzburg equation of a super-fluid, and from the Boltzmann equation the quantum potential of the Madelung transformed Schrödinger equation. Quantum mechanics is thereby explained as a completely deterministic theory, as required by Kant’s law of causality. This paper was inspired by a remarkable paper recently published by I. Licata [1], who compared the work by the author for a deterministic interpretation of quantum mechanics to the work of ‘t Hooft with the same goal.