Santorio, Regius, and Descartes: The Quantification and Mechanization of the Passions in Seventeenth-Century Medicine

In a letter to the German polymath Hermann Conring (1606–1681), Gottfried Wilhelm Leibniz (1646–1716) acknowledges both Santorio Santori (1561–1636) and René Descartes (1596–1650) as two authors whose methodologies had improved medicine, a discipline still lagging in curiosity and without a precise method.1 If Leibniz’s praise is easy to understand in the context of his correspondence, which positively refers to both Santorio and Descartes, the association of their names seems somewhat striking, for Descartes and Santorio are not usually related. First, their biographies differ, as Descartes never visited Padua, where Santorio was a professor, and Santorio died before Descartes’ publication of the Discours de la méthode in 1637. Second, their doctrines do not directly intersect: Descartes never mentions Santorio’s method or his instruments while he elaborates his own physiology.