1 Introduction -- 2 The formal elenchos appearing in the Principle of Non-Contradiction -- 3 The proof of the Protrepticus as an overcoming of formal elenchus -- 4 Some theoretical implications of the argument -- 5 Conclusion.

“We have the thesis, as radical as it is suggestive, of a syntactic-formal reduction of the principle of non-contradiction (Metaphysics IV), which must transcend itself into the principle of demonstration (Protrepticus). Read through the Aristotelian texts, the irreducibility of the principle of intelligibility to its determination will question and challenge both the theoretician and the historian of philosophy.” —Carlo Scilironi, Professor of Theoretical Philosophy, University of Padua, Italy. “The work shows that the authentic principle-ground can neither be determined nor obtained as the result of a proof, not even of the elenchus type, as in Aristotle's Metaphysics, but is that by virtue of which any proof is possible, as in Aristotle's Protrepticus, where it is shown that the necessity of philosophising is the ground even of its attempted negation. It will prove an essential reading for specialists in metaphysics.” —Ricardo Crespo, Professor of Philosophy of Economics, Austral University, Argentina. Numerous thinkers have considered the Principle of Non-Contradiction, but none has clearly identified its inherent limitation: that it is itself only a formal principle. This book shows that negation plays a fundamental role both in the constitution of the principle and in the affirmation of its value, which consists in its undeniability. Since it is a formal negation, it is extrinsic to the negated in such a way that it is configured as a negation only insofar as it is applied to something. On the basis of this analysis, it is shown that it is possible to reverse the usual philosophical perspective: it makes no sense to speak of proof of the principle, but only of proof by virtue of the principle. This book is essential reading for all scholars and researchers of theoretical philosophy and Aristotle. Aldo Stella, former Professor of Philosophy at the University of Urbino, is Professor of Psychology at the University of Perugia, Italy. Giancarlo Ianulardo is Senior Lecturer in Economics at the University of Exeter, UK.