The Collected Works of Descartes, Volume 1: Correspondence

The first volume also contains letters from Descartes and correspondents in the Netherlands. These are, first, letters LV and LVI, objections from a Reverend Jesuit Father with the responses. Clerselier could have known (as Descartes himself says in other letters) that this Jesuit was Father Ciermans, from the University of Louvain, who died in 1648. He could have also known—as we saw on the first page of this study—that the Physician from Louvain who made objections to which Descartes responded (letters LXXVII–LXXX) was Professor Plemp (Plempius), from the same University.

Finally, in the Netherlands, there still lived Henry de Roy (Regius), a Professor at the University of Utrecht. He was a great friend of Descartes between 1638 and 1646, but later became his enemy. Clerselier had a copy of Regius's letters in his hands; however, he did not publish them in 1657, even though doing so would have greatly helped in understanding Descartes’s responses—or rather, fragments of responses—in which far too many gaps are found. In the form they were published, they displeased Regius, and one of his friends complained in a book that “these responses from Descartes were things contrived and made to please” Meaning the friend accused Clerselier or Descartes of fabricating or doctoring the letters to favor Descartes’s arguments.. To justify himself, Clerselier then thought of publishing the actual letters from Regius to which Descartes was responding in the second edition of 1663. “But,” he says (p. 8 of his Preface to the Treatise on Man, 1664), “having written to Mr. de Roy, so as to do nothing except in cooperation with him, he would not allow it.” The second edition therefore appeared without Regius’s letters, and once again with Descartes’s letters truncated and mutilated, as Clerselier had discreetly complained as early as 1657 at the end of one of them (LXXXIV in the first edition, LXXXVII in the second): “The rest is missing. And if Mr. Regius wishes to act candidly and generously, he will supply it.” original Latin: “Deest reliquum. Et si candidè et generosè D. Regius velit agere, illud supplebit.” This was both a direct appeal to Regius to share the originals of the letters Descartes had written to him, and an allusion to the motto, candidly and generously original: “candidè et generosè”, which Regius himself had placed on his portrait at the beginning—