Given the locality assumption : p(ab|xy,λ) = p(a|x,λ) p(b|y,λ) with λ defining a single valued realism: a,b,a'b' each equal ± 1 the inequality S = (ab) + (ab') + (a'b) - (a'b') ≤ 2 is derived. Previously Bell pointed out that classical indeterminism wouldnt be enough for any hidden variable theory to overcome the restrictions imposed by the inequality. Then later, Science 177 880-881 1972 : Given that a hidden variable theory could be non deterministic , could evolve randomly even discontinuously so that values at one instant do not specify their values at the next instant. Bell. So if realism can be given up to explain inequality violations then why not also a non deterministic hidden variable theory ? How can the above inequality be derived when the past variable λ is not a constant with no restrictions on causal relationships. ?