On Three Unpublished Letters of Johannes de Raey to Johannes Clauberg

The present study aims to present a transcription and a commentary of three unpublished letters of the Dutch Cartesian philosopher Johannes de Raey (1620–1702), addressed to his former student Johannes Clauberg (1622–1665). Mainly containing suggestions concerning the defence of Cartesian philosophy and academic affairs, these letters, dating back to 1651, 1652 and 1661, bear witness of a steady friendship and of a certain cooperation in rebuking the critiques moved by Jacob Revius in his Statera philosophiae cartesianae (1650) and by Cyriacus Lentulus in his Nova Renati Descartes sapientia (1651), refuted in Clauberg’s Defensio cartesiana (1652). According to these letters, this cooperation had to be kept secret, not to provoke the reaction of Leiden theologians. However, the violation of the correspondence of Clauberg and De Raey occasioned the edition of Lentulus’s book and the rise of the polemics over the new philosophy. Eventually, such cooperation is to be noticed also in some crypto-quotations between the edited texts of Clauberg and De Raey.