This article discusses Leibniz’s claim that every substance is endowed with the property of perception in connection with Platonism, rationalism and the problem of substance monism. It is argued that Leibniz’s ascription of perception to every substance relies on his Platonic conception of finite things as imitations of God, in whom there is ‘infinite perception’. Leibniz’s Platonism, however, goes beyond the notion of imitation, including also the emanative causal relation and the logical (i.e. definitional) priority of the absolute over the (...) limited. It is proposed that Leibniz’s endorsement of Platonism, in conjunction with some rationalist elements of his philosophy, implies a monistic conception of particulars as modifications of a single substance. Following some scholars and opposing others, the article offers evidence that Leibniz accepted this implication during the last years of his Paris period. However, it is further argued that it was precisely the idea of perception as a property of every substance that allowed Leibniz to find a way out of monism after that period. More specifically, the article defends the view that what made room for ontological pluralism within Leibniz’s rationalist and Platonic outlook was the idea that perception is the property which constitutes the very being of substances: substances are their perceptions. (shrink)

Leibniz frequently uses the notion of expression, but it is not easy to see just how he understood that relation. This paper focuses on the particular case of the expression of God, which is prominent in the 'Discourse on Metaphysics'. The treatment of expression there suggests several questions. Which substances did Leibniz believe expressed God? Why did Leibniz believe those substances expressed God? And did he believe that all substances expressed God in the same way and for the same reasons? (...) In answering those questions the paper distinguishes two views about expression in the 'Discourse', considers Leibniz's reasons for holding that substances express their causes, and argues that Leibniz's views about emanative causation are important for understanding the unity of his apparently distinct views here. The paper concludes by looking briefly at how the 'Discourse' fits into the evolution of Leibniz's views on this issue over time. (shrink)