  The following is an informal reconstruction of the Master Argument which has the advantage of being historically credible and in keeping with the above constraints. (A version of this type of reconstruction was first presented by Arthur Prior (Prior 1955).) The Epictetus passage suggests that the argument was presented in terms of propositions and their modalities, and so will the reconstruction. Other sources present Diodorus' modalities as modalities of states of affairs, and alternative versions of the Master argument can be produced accordingly. (The difference between propositions and states of affairs is often blurred in ancient testimonies of logic.)