 And in the Essais de théodicée Leibniz uses the analogy of a heavy-laden boat travelling down a river to explain how God and finite substances can be said to co-operate in the production of particular effects in the ordinary course of nature (T 30–1). Both the metaphor and the analogy provide useful but imperfect devices for conceiving of things that cannot be sensed or imagined, strictly speaking. In reading Leibniz’s texts it is important to recognize that these are only metaphors and analogies—they are not meant to provide metaphysically rigorous descriptions of divine action (see Whipple 2015b).