ABSTRACT
Knowledge of the classical and nonclassical theories of logical propositions is not required for an understanding of the analysis of the nonseparability of systems. Some very elementary notions about that matter may help to place the general problem in appropriate perspective. Classically, physical propositions bear upon physical systems. A proposition a bearing on a system S is a qualitative statement about S. The quantum calculus of propositions has been successfully used as an alternative and more general basis for the foundations of quantum mechanics. It is a truism that the advent of the modern physical theories—relativity, quantum mechanics, quantum electrodynamics, S matrix theory, and so on—has induced us to abandon many familiar intuitive concepts. All the successful theories mentioned above are built on elaborate sets of axioms that are justified only a posteriori, that is, by agreement between some of their consequences and observed facts.
