Deeply complicating matters, 0 and 1 can be excluded from theories of probability, and there is a good informal reason to do it, known as Cromwell’s rule. The issue is that there no longer are units in such a system; 0 is the disjunctive unit and 1 is the conjunctive unit. This is part of a bigger theme in maths where units are increasingly seen as optional, but Yud is completely unaware of this bigger theme.