Abstract
A number of recent studies have called into question the traditional interpretation of Leibniz as an idealist beginning, at the latest, with the composition of the Discourse on Metaphysics (1686). In particular, in a recent book Daniel Garber affirms that between the late 1670s and late 1690s Leibniz maintains a realist doctrine according to which the created world is populated with extended corporeal substances. In trying to prove his thesis, Garber appeals to a document written in 1690 where Leibniz, addressing an objection by Michelangelo Fardella, denies that bodies are composed of souls, declares that souls are substantial forms, and affirms that bodies are composed instead of substances. According to Garber, this shows that Leibniz then believed that bodies were composed, not of simple substances, but of extended substances possessing souls. Here I try to show that, to the contrary, the mentioned document (along with two others closely associated with it) support the traditional interpretation of Leibniz as an idealist in 1690.