Every phenomena within physics, from entanglement to time dilation, is conceptually derivable from the definition of existence, P(Z)E(Z), by applying the rules of inference within classical logic. This establishes that it is classical logic that describes what is possible in our universe, and physics provides the mathematical descriptions. When physics is developed before the underlying ontology is understood: 1) paradoxes can occur where the equations deviate from the way reality actually behaves; and 2) quantum phenomena has appeared mysterious even though all phenomena are conceptually derivable using the definition of existence and classical logic. In this case, ontology tells us how to resolve paradoxes by establishing what the equations should be describing, and how to correctly interpret them.