
 Quantum Logic and Probability Theory 
  Mackey presents a sequence of six axioms, framing a very conservative generalized probability theory, that underwrite the construction of a ‘logic’ of experimental propositions, or, in his terminology, ‘questions’, having the structure of a sigmaorthomodular poset. 
  In classical probability theory (and especially in classical statistics) one usually focuses, not on the set of all possible probability weights, but on some designated subset of these (e.g., those belonging to a given family of distributions). 
  Because of this, the set of probabilitybearing events (or propositions) is less rich than it would be in classical probability theory, and the set of possible statistical distributions, accordingly, less tightly constrained. 
 plato.stanford.edu /entries/qtquantlog (7961 words) 
