Scott Harkema

In her Discourse on Happiness, Émilie Du Châtelet claims that one must be susceptible to illusions to be happy. She gives almost no explanation of what illusions are or what causes them, and thus the claim appears to lack an adequate defense. I offer an account of Du Châtelet’s theory of illusion by drawing upon the previously unexamined influence of other French philosophers’ accounts of the connection between passion and illusion, including Descartes, Malebranche, and Anne-Thérèse, Marquise de Lambert. According to this tradition, the passions misrepresent their objects in the imagination, and these misrepresentations can be referred to as “illusions.” Attributing this theory of passionate misrepresentation to Du Châtelet solves two puzzles about illusion that arise in the Discourse. First, it explains why she claims illusions are necessary for happiness. Second, it explains how illusions can be distinguished from cognitive errors made in other domains, like philosophy and natural science.

Studies of the Early Modern debate concerning absolute and relative space and motion often ignore the significance of the concept of true motion in this debate. Even philosophers who denied the existence of absolute space maintained that true motions could be distinguished from merely apparent ones. In this paper, I examine Berkeley's endorsement of this distinction and the problems it raises. First, Berkeley's endorsement raises a problem of consistency with his other philosophical commitments, namely his idealism. Second, Berkeley's endorsement raises a problem of adequacy, namely whether Berkeley can provide an adequate account of what grounds the distinction between true and merely apparent motion. In this paper, I argue that sensitivity to Berkeley's distinction between what is true in the metaphysical, scientific, and vulgar domains can address both the consistency and the adequacy problems. I argue that Berkeley only accepts true motion in the scientific and vulgar domains, and not the metaphysical. There is thus no inconsistency between his endorsement of true motion in science and ordinary language, and his metaphysical idealism. Further, I suggest that sensitivity to these three domains shows that Berkeley possesses resources to give an adequate account of how true motions are discovered in natural science.