In the 1680s, Gottfried Leibniz and Antoine Arnauld engaged in a philosophically rich correspondence. One issue they discuss is modal metaphysics – questions concerning necessity, possibility, and essence. While Arnauld's contributions to the correspondence are considered generally astute, his contributions on this issue have not always received a warm treatment. I argue that Arnauld's criticisms of Leibniz are sophisticated and that Arnauld offers his own Cartesian account in its place. In particular, I argue that Arnauld offers an account of possibility (...) that is actualist, modal actualist and essence-based. (shrink)

According to one of Leibniz’s theories of contingency a proposition is contingent if and only if it cannot be proved in a finite number of steps. It has been argued that this faces the Problem of Lucky Proof, namely that we could begin by analysing the concept ‘Peter’ by saying that ‘Peter is a denier of Christ and …’, thereby having proved the proposition ‘Peter denies Christ’ in a finite number of steps. It also faces a more general but related (...) problem that we dub the Problem of Guaranteed Proof. We argue that Leibniz has an answer to these problems since for him one has not proved that ‘Peter denies Christ’ unless one has also proved that ‘Peter’ is a consistent concept, an impossible task since it requires the full decomposition of the infinite concept ‘Peter’. We defend this view from objections found in the literature and maintain that for Leibniz all truths about created individual beings are contingent. (shrink)