 The key property of living matter, and of all matter potentially, is organic sensitivity. Diderot often suggests that “sensitivity or touch is common to all beings”, and he often attributes sensitivity to matter as a whole (EP; DPV XVII: 308). In “Leibnizianisme”, he brings together Aristotle’s entelechy, Leibniz’s monads, and sensitivity as a “general property of matter” (Enc. IX: 371); indeed, Leibnizian metaphysics and theories of generation had a great impact on eighteenth-century thought, and has been viewed as major influences in the formulation of Diderot’s materialism, albeit in naturalized form, e.g: “the monad, the real atom of nature, the true element of things” (Enc. IX: 374a). Elsewhere, such as the 1765 Letter to Duclos, Diderot denies that sensitivity can be a property of a molecule, specifically because it can only be a property of matter itself. He then complicates the issue further by introducing a distinction between “inert” sensitivity and “active” sensitivity.