In The Fold, Deleuze regards Raymond Ruyer as the most recent of Leibniz’s great disciples. This claim is not self-evident, since Ruyer often criticises Leibniz and stresses the divergence of his theory from Leibniz’s monadological metaphysics. Therefore, while Ruyer does not seem to regard himself as indebted to Leibniz, and as his psychobiology is not always reconcilable with Leibniz’s philosophy, it is necessary to explore what is at stake in Deleuze’s recognition of Ruyer as a Leibnizian thinker. This essay foregrounds (...) the tacit intertwining between Leibniz and Ruyer, which can, on the one hand, contribute to Leibniz’s scholarship and uncover the contemporaneity of his thought, and on the other hand, expose certain revealing Ruyerian moments in Deleuze’s immanent philosophy. (shrink)