The Vienna Experiments show that quantum indeterminacy has mathematical origins, rather than originating in any unknown physics. This chapter sets the tone for mathematical discipline needed in exposing those origins; and demonstrates an example of easy-to-access logic, visibly manifest in Quantum Mathematics, which textbook theory ignores.

Emphasis is on Quantum Mathematics: the mathematics representing Quantum Mechanics; because quantum indeterminacy originates in mathematical processes. The mathematics permits semantical freedom for pure states, not permitted for mixed states; possible unitarity applying to pure states, and necessary unitarity applying to mixed states. A priori unitarity, imnposed across all states of a quantum system, is not truly or faithfully representative. The traditional formalism of Applied Mathmeatics is inadequate in exposing the semantical freedoms; the formalism of quantifier logic is needed.