Appetimus sub ratione boni: Kant’s Practical Principles between Crusius and Leibniz

For Leibniz, freedom cannot consist in an ability to act without any sufficiently determining cause. That would violate the principle of reason, replacing God’s omniscience and omnipotence with “the chance of the Epicureans” 1 . But, of course, Leibniz is equally concerned to avoid the necessitarianism represented by Spinoza and the “the sect of new Stoics” 2 , and to this end he argues for the metaphysical contingency of created nature. But it is important to see that, for Leibniz, since all of nature is contingent, contingency is far from constituting a sufficient condition for freedom: what distinguishes human beings from the rest of nature is not the contingency of their actions, but rather the fact they are intelligent (Theodicy, §34). Leibniz thus defines ‘freedom’ variously as rational spontaneity (spontaneitas rationalis) (Ak. VI.4: 1380), as spontaneity with intelligence (spontaneitas intellegentis) (Gerhardt 7:108) or as the property of being “spontaneous with choice” (spontaneum cum electione) (Ak. VI 3: 133). By this, Leibniz means that we act according to a conception of what is good: “The free substance is self-determining and that according to the motive [le motif] of good perceived by the understanding, which inclines it without compelling it” 3 . In finite beings, this conception of the good may be very mistaken: “free will tends toward good, and if it meets with evil it is by accident, for this evil is concealed beneath the good” (Theodicy, §154). But in every case a will without any (sufficiently determining) motive is a fiction (Gerhardt 7:371f.). In the Nova dilucidatio of 1755, Kant defends an account of human freedom that is Leibnizian in the relevant respect: the freedom of the will is not a freedom from causal determination, but rather the will’s ability to choose whatever seems best. On this account, the actions of a human being are necessitated by a sufficiently determining cause, but are still free since they are not determined by the “external enticements and impulses” (sollicitationes et impulsus externi) that necessitate “animal or physico-mechanical actions” (actiones brutae s.