This review examines a unified naturalism or theories of everything that include both the natural universe and subjective consciousness, by applying two critical filters to theories of existence, including those surveyed in Robert Lawrence Kuhn’s (2024) “Landscape of Consciousness”, hereinafter referred to as LoC: (1) The No Supervenience (NS) theorem, which asserts that subjective consciousness is not supervenient on the physical universe, and (2) The Principle of Natural Empiricism critical to experimental scientific discoveries and empirical experiences. (1) is equivalent to accepting that the explanatory gap of the hard problem of consciousness rules out implicitly physicalist and other TOEs that invoke functionalistic processes dependent on physical causality, to explain subjective consciousness. The NS theorem has the same effect as accepting that the Hard Problem of Consciousness is real, or that materialistic physicalism is false. The difficulty of the hard problem, which remains unresolved 26 years later, is also tied to the likewise unresolved problem of assumed causal closure of the universe in brain function at the basis of pure materialistic neuroscience. Until this conjecture is empirically confirmed, causal closure remains simply a matter of opinion, that has grown into a belief system, academically prejudiced against hypotheses not compliant with the physical materialistic worldview.