  Recent results obtained in quantum measurements indicate that the fundamental
relations between three physical properties of a system can be represented by
complex conditional probabilities. Here, it is shown that these relations
provide a fully deterministic and universally valid framework on which all of
quantum mechanics can be based. Specifically, quantum mechanics can be derived
by combining the rules of Bayesian probability theory with only a single
additional law that explains the phases of complex probabilities. This law,
which I introduce here as the law of quantum ergodicity, is based on the
observation that the reality of physical properties cannot be separated from
the dynamics by which they emerge in measurement interactions. The complex
phases are an expression of this inseparability and represent the dynamical
structure of transformations between the different properties. In its
quantitative form, the law of quantum ergodicity describes a fundamental
relation between the ergodic probabilities obtained by dynamical averaging and
the deterministic relations between three properties expressed by the complex
conditional probabilities. The complete formalism of quantum mechanics can be
derived from this one relation, without any axiomatic mathematical assumptions
about state vectors or superpositions. It is therefore possible to explain all
quantum phenomena as the consequence of a single fundamental law of physics.
