The Leibniz Review

The mature Leibniz frequently uses the phrase “moral necessity” in the context of discussing free choice. In this essay I provide a seventeenth century geneology of the phrase. I show that the doctrine of moral necessity was developed by scholastic philosophers who sought to retain a robust notion of freedom while purging bruteness from their systems. Two sorts of bruteness were special targets. The first is metaphysical bruteness, according to which contingent events or states of affairs occur without a sufficient explanation. The second is semantic bruteness according to which a proposition can be true without a truth maker. Denying eithersort of bruteness was thought by some to raise problems for freedom. Defenders of moral necessity thought the notion solved these problems without having to invoke bruteness.

Leibniz’s De incerti aestimatione, which contains his solution to the division problem, has not received much attention, let alone much appreciation. This is surprising because it is in this work that the definition of probability in terms of equally possible cases appears for the first time. The division problem is used to establish and test probability theory; it can be stated as follows: if two players agree to play a game in which one has to win a certain number of rounds in order to win the pool, but if they break the game off before either of them has won the required number of rounds, how should the pool be distributed?Our article has two aims: it provides the readers with the first published English translation of De incerti aestimatione, and it also gives them a brief commentary that explains Leibniz’s philosophical and mathematical concepts necessary in order to understand this work. The translation is as literal as possible throughout; it shows how Leibniz struggled at times to find a solution to the division problem and how he approached it from different angles. The commentary discusses Leibniz’s views on four key concepts: fairness, hope, authority and possibility. The commentary then outlines how Leibniz attempted to solve the problem of division.