Abstract

A proposition is true, according to Leibniz, if the concept of the subject of the proposition contains the concept of its predicate; but the "the" in this statement of Leibniz's definition of truth is misleading with respect to singular propositions. Leibniz's characterization of individual subjects entails that they have many nonequivalent individual concepts. At most one of these concepts contains the concept of the world an individual actually exists in and the properties the individual has as a result of existing in it. Other individual concepts of an individual subject, however, contain the concepts of other worlds the individual possibly exists in and truths about the individual which would be actually true of it if the individual actually existed in those worlds. ;In my dissertation I argue that the fact that Leibnizian individuals have many nonequivalent individual concepts is the foundation of Leibniz's doctrine that existing individuals can have properties other than those they happen to have. But, given that an individual exists in the world that it does, it cannot fail to have any of the properties that it in fact has. Leibniz maintained, nevertheless, that there is no necessary connection between the conditions that an individual subject is found in and the properties which it has because the connection between them cannot be demonstratively established in a finite number of steps. ;Leibniz regarded a proposition as being logically necessary if it can be demonstrated in a finite number of steps. He also maintained that a condition for a human action being necessary is that the proposition which asserts it be logically necessary, and for him such a proposition is not necessary. A proposition may therefore be, for Leibniz, logically contingent but at the same time its denial not be possibly true. I argue in my dissertation that this is why Leibniz offers two accounts of contingency. His"possible worlds" account of contingency is intended to explain the possibility of things being otherwise but does not touch the problem of human freedom; and his "proof-theoretic" account of contingency is meant to explain human freedom but does not answer the question of how individuals can be possibly otherwise