 Bohm of course was well aware of these features of his scheme, and has given them much attention. However, it must be stressed that, to the present writer’s knowledge, there is no proof that any hidden variable account of quantum mechanics must have this extraordinary character. It would therefore be interesting, perhaps, to pursue some further “impossibility proofs”, replacing the arbitrary axioms objected to above by some condition of locality, or of separability of distant systems. (Bell 1966: 452; reprinted 1987c: 11) 