This paper presents an interpretation of the main arguments used in Peter Olivi’s Treatise on Demons, published circa 1295 in Narbonne, Languedoc, within a rational-choice framework. This book has been widely praised as a landmark in the philosophical literature on personhood and personal freedom, since it was (re)discovered about a century ago. In it, Olivi discusses most of the relevant classical and medieval literature on this topic before stating his own position. In the scholastic tradition, the book does not make for easy reading. Moreover, it is evidently a “work in progress”, as pointed out by the translator. Many paragraphs end with “Ergo, etc.”, suggesting that he planned to add something, but could not find time enough for that. He died in 1298, aged 50. This paper offers a simple game-theoretic model aimed at articulating Olivi’s main arguments in a consistent rational choice framework, supported by many quotes translated from French into English by me. It suggests that the “fall of the devil” is used as a parable on human freedom and agency, given a set of incentives strategically chosen by “God” to minimize the number of “sinners”, with some potential interference by “Lucifer”.
IAST Working Paper, n. 23-157, October 2023