Einstein was enamored with the philosophies of Schopenhauer and Spinoza, in Schopenhauer's conception of the will and Spinoza's pantheism. The God of Spinoza (or indeed Einstein) is strictly deterministic, and we are all a part of such a God, as is all of nature. Hence his quote 'God does not play dice', and in part it explains Einstein's philosophical commitment against some of the indeterministic interpretations of quantum physics being ultimately true.