Title: "Deontic Logic and the Origin of Leibniz’s Theory of Modality"
Abstract: In this paper I argue that a system of deontic logic developed by Leibniz in the latter half of 1671 sheds light on both why he became committed to the contingency of the actual world and the nature of the contingency he endorses. Under Leibniz’s deontic logic, if necessitarianism is true, every action becomes obligatory and moral assessment of agents on account of their actions becomes impossible. The system also suggests a way out of this problem: to avoid these consequences one need only posit alternative courses of action that are possible in themselves, even if they may be necessary for a given agent. Leibniz’s theory of contingency, based on the per se possibility of alternatives, is therefore sufficient for his purposes and justifies contingency on his own terms. Moreover, the development of this deontic logic is likely the terminus a quo of Leibniz’s theory of modality.
Sponsored by The Edward J. and Dorothy Clarke Kempf Fund at Yale University.
