French Scholasticism's Long Encounter with Descartes

Adamson argues that since Scholasticism defined medieval philosophy and continued at French universities into the 18th century, the medieval period arguably did not end until the French Revolution. University masters were still being criticized on the eve of the Revolution for repeating old theses.

Adamson describes ongoing 17th century disputes between followers of Aquinas and Duns Scotus over whether being applies to God and creatures univocally or analogically, whether substances have one or many forms, and the principle of individuation. This internal pluralism gave scholastics room to maneuver even before confronting Cartesianism.

Adamson explains that scholastics largely rejected heliocentrism but often embraced Tycho Brahe's compromise system, since it fit both observed phenomena and scriptural statements about the sun's motion. He quotes a 1675 scholastic who says the intellect must be held captive to scriptural authority even against natural reason.

Adamson argues that Descartes used scholastic terminology, sought Mersenne's advice on which scholastic texts to consult, and included a Jesuit among the objectors to the Meditations, all to persuade rather than defeat the schoolmen. Descartes even praised Eustachius of Santo Paolo's compendium as the best work on scholastic thought.

Adamson traces middle-path figures like Morin and Duhamel alongside more polarized reactions: the Oratory both nurtured Cartesians like Malebranche and Bernard Lamy and later banned teaching Descartes' physics, while the Church placed Descartes' works on the Index of Prohibited Books.

Adamson highlights an anonymous Cartesian treatise, likely by Arnauld, arguing it would be tactically unwise for the Church to insist Descartes' physics contradicted the Eucharist, since so many people accepted the new physics that pressing the point would undermine the Church's own credibility. Adamson calls this a seismic shift from the earlier assumption that philosophy must yield to Church doctrine.

Adamson describes how scholastic logic textbooks incorporated a Cartesian-style psychological approach to reasoning while still relying on traditional Aristotelian material, and how scholastics accepted methodic doubt as useful but grounded certainty in the principle of non-contradiction rather than the cogito. He also covers the Jesuit ethical theories of probabilism and laxism, later condemned by the Church.

Anti-Cartesian churchmen held that Descartes' physics was incompatible with the Church's understanding of the Eucharistic miracle and pushed to suppress Cartesianism, leading to Descartes' works being placed on the Index. Arnauld argued the opposite: that pressing this objection would be tactically unwise and would undermine the Church's own authority given how widely the new physics was accepted.

A 1671 Cartesian burlesque mocked Church authorities for declaring widely accepted discoveries false and for banishing reason from the universities. A theology professor at Angers satirically defended old truths against the fashionable denial of substantial forms and belief in innate ideas.

Descartes held that the cogito, I think therefore I am, is the foundational certainty for philosophy. Scholastics who otherwise accepted Cartesian methodic doubt instead held that the Aristotelian principle of non-contradiction was the most certain axiom of reason.