Abstract
I first show in this paper how twentieth century Set Theory got into its greatest tangle by, amongst other things, regarding relational remarks like ‘Rxy’ asbinary functions. I then show how the lack of indexicality, and of ‘that’-clauses, in Modern Logic led that subject into its intractable difficulties with the Theory of Truth. Both errors arose not only through a contempt for ordinary language, but also through the related failure to recognise that being logical is not a matter of being brainy, but of being coherent. It is not a mathematical talent, but a literary one. Later in the paper I go on to demonstrate this same conclusion with respect to Modal Logic and General Intensional Logic, and in particular with respect to fictions, since these are the central items that have been misunderstood, as is witnessed in some recent writings of Graham Priest.