Abstract

In the Monadology Leibniz has us imagine a thinking machine the size of a mill in order to show that matter can’t think, or, in his terms, cannot have perceptions: his well-known Mill Argument. The argument is often thought to rely on the unity of consciousness and the notion of simplicity. Leibniz himself did not see matters this way. For him the argument relies on the Cartesian “Mode-Nature View”, and the idea that perception is not a modification of matter because perception is active and matter is passive. At the same time, there are traces in Leibniz of a different argument that relies on the idea that perception is an “internal” action, an action of a thing on itself as opposed to an “external” action, where a thing acts on a different thing.