Passions of the Soul
In his final philosophical treatise, The Passions of the Soul (French: Les Passions de l'âme), completed in 1649 and dedicated to Princess Elisabeth of Bohemia, the French philosopher and mathematician René Descartes contributes to a long tradition of philosophical inquiry into the nature of "the passions". The passions were experiences – now commonly called emotions in the modern period – that had been a subject of debate among philosophers and theologians since the time of Plato.