Abstract

The “problem of voluntary actions”, traditionally known asthe “problem of substantial union”, is one of the most controversialissues in the Cartesian doctrine. It is about seeking to understand howthe soul, being just an immaterial substance, whose nature consists onlyin thinking, could determine the animal spirits to carry out voluntary actions.The modus operandi, from which Descartes intended to explain howthe thinking substance would determine the movements of the pinealgland, is what greatly botheredElisabeth of Bohemia. In this article, we will present the central aspectsof Descartes’ responses to the problem raised by the princess, especiallywhen trying to show that he is insoluble, because, according to the philosopher,it is a poorly formulated question. Thus, in his correspondencewith Elisabeth, the role of the philosopher is limited to identifying and clarifying mistakes, which certainly did not satisfy Elisabeth’s philosophicalgenius.