 However, Nicholas Jolley, among others, insists that “[a]lthough Leibniz may say that it is substances which produce their states, this is only a loose way of speaking” (Jolley 1998, 605). Strictly speaking, according to Jolley, substance A caused perceptual state p2 is shorthand for there is some perceptual state p1 such that p1 involves A and p1 causes p2 (Jolley 1998, 605). But does Leibniz indeed take perceptions or perceptual states to be efficient causes? The answer is surprisingly unclear. One problem is that (almost) invariably the language Leibniz employs to describe the relationship among perceptions or perceptual states is not explicitly causal (in the efficient or productive sense at least). Leibniz predominantly uses terms such as ‘consequence’, ‘suite’, ‘sequitur’, ‘résultat’, ‘tend’, and ‘derivantur’, when speaking of the passage from one perceptual state to another (GP ii 47, 91f, 372; GP iv 440, 521), terms which should make us hesitate in automatically attributing to Leibniz a theory of causally efficacious perceptions or perceptual states. Consider the following representative sample of texts: