"Einstein did not consider the concept of 'determinism' to be as fundamental as it is frequently held to be (as he told me emphatically several times), and he denied energetically that he had ever put up a postulate such as (your letter, para. 3): 'the sequence of such conditions must also be objective and real, that is, automatic, machine-like, deterministic'. In the same way he disputes that he uses as criterion for the inadmissibility of a theory the question: 'Is it rigorously deterministic?' Einstein's point of departure is 'realistic' rather than 'deterministic,' which means that his philosophical prejudice is a different one..."