An Etymological Dictionary of Astronomy and Astrophysics

A theory in which specification of the initial value of all relevant variables of the system is sufficient to calculate the past values and
to predict the future values of such variables for any arbitrary
time. Moreover, it is possible, for any arbitrary time, to assign a value to all the variables characterizing the system. In quantum mechanics, the time evolution of the → wave function, governed by the → Schrodinger equation, is deterministic. Quantum mechanics, however, is a non deterministic theory because of the probabilistic nature of the predictions for the values of the → observables of a quantum system.

See also: → deterministic; → theory.