This article is about the exchanges between Leibniz, Arnauld, Bayle and Lamy on the subject of pain. The inability of Leibniz’s system to account for the phenomenon of pain is a recurring objection of Leibniz’s seventeenth-century Cartesian readers to his hypothesis of pre-established harmony: according to them, the spontaneity of the soul and its representative nature cannot account for the affective component of pain. Strikingly enough, this problem has almost never been addressed in Leibniz studies, or only incidentally, through the (...) more general problem of evil. My purpose in this article is to clarify Leibniz’s psychophysical parallelism by opposing his representationist account of pain to the functionalist account endorsed by Arnauld, Bayle, Lamy and Malebranche. (shrink)