Leibniz on Necessary and Contingent Truths

Abstract

The distinction between necessary and contingent truths has so much important role in the explication of Leibniz’s philosophy of logic, metaphysics, and philosophy of science that the distinction spreads throughout most of his philosophical writings. My aim in this paper is to try to provide a clear and detailed account of some of the aspects of Leibniz’s distinction between necessary and contingent truths. This paper is divided into four parts. In the first part, an analysis of Leibniz’s general notion of “truth” (“the Principle of the Predicate-in-Notion”) is given. This will be followed by his distinction between necessary truths and contingent truths, which he also terms as “truths of reason” and “truths of fact” respectively. Thirdly, the implication of this distinction in Leibniz’s theory of human freedom will be addressed. I will end my discussion with an answer to the following questions: The distinction goes traditionally under Leibniz' name; but is it his own invention, or has he merely picked it up from one of his predecessors? And secondly, how far this distinction has an impact (if any) on the philosophies of his contemporaries, especially on Wolff, Hume and Kant?