Metaphysical naturalism holds that all concrete substances are mereologically reducible to fundamental particles and energy. Following this premise, all constituents of the universe, including the human mind, are confined to this reductionism. This means that all phenomena can be explained by appealing to the causal relationship between fundamental particles guided by the impersonal forces of physics. If the physical laws governing matter and energy are the sole source for which all instances of change originate, then all states of human thought are deterministically actualized by antecedent members in a series of accidentally ordered events. Fundamental physical structures, blindly coerced into deterministically necessary states, do not have within them the capacity for propositional knowledge. This means that intellectual state of affairs lack the ability to facilitate propositional knowledge. However, this conclusion is self-contradictory, so the assumption from which it was derived must be rejected, falsifying metaphysical naturalism.