ABSTRACT
This chapter explains Gottfried Wilhelm Leibniz' theory of necessity by first considering views elaborated by four of his predecessors—Aristotle, Aquinas, Nicholas of Autrecourt, and Thomas Hobbes. Leibniz will be found to differ from Aristotle to the extent of speaking almost exclusively of necessity as a property of propositions, the subject and predicate terms of which are related in a particular way. St. Thomas’ pronouncements on necessity, although of course strongly influenced by Aristotle, contain some interesting innovations which point to the direction in which the concept was to be developed by Leibniz. Nicholas, in his First and Second Letters to Bernard, accepts the Aristotelian view that the principle of non-contradiction is the first principle of all demonstration, but criticizes Aristotle for not recognizing that this position entails an extremely limited view of the possibilities of human knowledge. Leibniz incorporates within his system the traditional distinction between absolute and hypothetical necessity.
