Abstract

The main original view I defend is that most of his life Leibniz thought of existence as an external quality, i.e., as a supervenient property. Furthermore, along the work I show other findings and provide new and original arguments for current interpretations of Leibniz's views on existence. ;I apply Hector-Neri Castaneda's Darwinian method to defend, contra Russell, that Leibniz sincerely held around 1677 a non-theistic view on the origin of things, and that he did not see existence as a perfection in three ocassions: in his correspondence with Eckard, when he saw it as a relation of comparison, and in 1686, when he saw it as a copula. ;I defend the intensionalist interpretation of Leibniz's logic, against the extensionalist reading of Couturat, the Kneales, C. I. Lewis, Walter O'Briant and Hector-Neri Castaneda. I argue that his ontology led him to devise his notional logic. Furthermore, I argue that such a logic allowed him to provide a satisfactory proof of subalternation, which he could not provide within an extensional framework. I also show that Leibniz anticipated conditional, existential import-free, reading of universal affirmatives, and that he devised a notation, along with the concept of coincidence, to give an account of both existential and essential propositions. ;I provide textual evidence that Leibniz used three different concepts of perfection, and provided different definitions of the concept of existence. I also show and examine Leibniz's struggle between the univocity and the equivocity of 'existence' theses and defend that the former suits better his ontology and was finally embraced by Leibniz, against Jalabert's interpretation. ;Against Parkinson's opinion, I show how an analysis of existential statements can be drawn from Leibniz's logical analysis on contingent propositions. ;As for his epistemological views, I show the importance that Leibniz gave to the criteria of congruence and predictability, although he abandoned temporarily the criterion of congruence, and I defend that his phenomenalism was non-reductionistic. ;Finally, I show Suarez's influence on Leibniz and defend that Leibniz's ontology is an ontology of existent and non-existent objects