There are three categories of theories relevant here: Deterministic classical mechanics Non deterministic interpretations of quantum mechanics (most popular a

There are three categories of theories relevant here: Deterministic classical mechanics Non deterministic interpretations of quantum mechanics (most popular among physicists) Deterministic interpretations of quantum mechanics (eg Bohmian mechanics) In the first case, the future is calculable in principle, but probably not in practise (too complex) In both of the other two cases, it is incalculable in principle, even though the latter is deterministic