The Fifth Corner of Four: An Essay on Buddhist Metaphysics and the Catuṣkoṭi

Graham Priest presents an exploration of Buddhist metaphysics, drawing on texts which include those of N g rjuna and D gen. The development of Buddhist metaphysics is viewed through the lens of the catuṣkotị. At its simplest, and as it appears in the earliest texts, this is a logical/ metaphysical principle which says that every claim is true, false, both, or neither; but the principle itself evolves, assuming new forms, as the metaphysics develops. An important step in the evolution incorporates ineffability. Such things make no sense from the perspective of a logic which endorses the principles of excluded middle and non-contradiction, which are standard fare in Western logic. However, the book shows how one can make sense of them by applying the techniques of contemporary non-classical logic, such as those of First Degree Entailment, and Plurivalent Logic. An important issue that emerges as the book develops is the notion of non-duality and its transcendence. This allows many of the threads of the book to be drawn together at its end. All matters are explained, in as far as possible, in a way that is accessible to those with no knowledge of Buddhist philosophy or contemporary non-classical logic.