Theoretical nous in the posterior analytics

According to Aristotle's definition of episteme (understanding) in the Posterior Analytics, you have episteme of the proposition that P when you know why P, and you know that it is necessary that P. Episteme is therefore only available for propositions which have an explanation, i.e. the theorems of the science. It is a demanding cognitive state, since knowing the explanation of a proposition in a science requires being able to demonstrate or prove it. Aristotle occasionally refers to the counterpart notion to episteme which applies to propositions which lack an explanation, i.e. the first principles of a science. This counterpart notion is nous, or non-demonstrative understanding. Aristotle never defines it, but it should turn out to be an equally demanding cognitive state to achieve. This paper proposes that you have nous of the proposition that P when you know that nothing explains why P, you know the various ways in which the proposition that P features in explanations in the science, and you know that it is necessary that P.