 Part of what troubles Leibniz about the doctrine of physical influx is that in acting, the cause is drained. According to Leibniz, real causation entails that the cause not lose any of its efficacy after exercising its causal power. Leibniz depicts the production of our thoughts, for instance, as involving emanative causation: “it is very evident that created substances depend upon God, who preserves them and who even produces them continually by a kind of emanation, just as we produce our thoughts” (Discourse on Metaphysics §14 GP iv, 439/AG 46). Other commentators have put it this way: “[S]ubstances are to be understood as enjoying a lawful primitive force of action whereby accidents emanate from the substance, from within” (Cover &amp; O’Leary-Hawthorne, 181).