... lefthand side then it must be in B ∩C, therefore it is also in the righthand side. If ω /∈ A and it is in the r ighthand side, then it must be both in B and in C,therefore i t is in the lefthand ... example of rolling two indistin-guishable dice. Observable events may be: getting two ones, getting a one and a two,etc. But we cannot distinguish between the first die getting a one and the ... inde-terminacy, since the polarized photons form a pure state, which is atomic in the algebra of events. In this case, the distinction be tween epistemic un-certainty and ontological indeterminacy...