Descartes: A Biography

c CUNYB/Clarke     December, :

Magic, Mathematics, and Mechanics 

During these years, Descartes also became acquainted with the mathe-

matician Jean-Baptiste Morin, with whom he later discussed the Earth’s

motion, and with the Oratorian priest Guillaume Gibieuf (–).

Gibieuf was thirteen years older than Descartes; he had enjoyed a similar

Jesuit education at the college in his native town of Bourges, and he had

subsequently joined the Oratory infollowing studies at the Sorbonne.

He was thus ideally placed to offer Descartes the theological support that

he needed when faced with challenges about his religious orthodoxy. This

was especially true on the contentious issue of how human freedom is

compatible with God’s causal influence over human actions.Descartes

also first met the man who was usually identified as Abbe Picot, who acted ́

subsequently as manager of his business affairs and who remained a friend

to the end of Descartes’ life.

There were two significant events in Descartes’ life during this period:

his meeting with Berulle and the siege of La Rochelle, although the dat- ́

ing of the former remains unclear. In autumn,Descartes attended

aconference given by Chandoux in the presence of Cardinal B ́erulle, the

founder of the Oratory, and of the papal legate Cardinal Bagni. Descartes’

intellectual skills in refuting point by point the various arguments pro-

posed prompted Berulle to ask him whether he had a method by which ́

philosophical questions could be resolved. The young philosopher claimed

that he was working on such a method – he had in his study an incom-

plete version of theRules, about half the projected set of thirty-six rules

of method – and he promised his host to make available the results of his

reflections. He reported this event in a letter to Villebressieu in:

Youhaveseen the two results of my fine rule or natural method when I was obliged

to apply it in the discussion I had with the Papal Nuncio, Cardinal Berulle, Father ́

Mersenne, and with the large and learned group that assembled at the home of the

Nuncio to hear Mr. Chandoux’s discourse about his new philosophy. That is where

I made the whole group acknowledge the power that reasoning properly has over the

minds of those who are only moderately learned, and the extent to which my principles

are better established, more true and more natural than any others which are currently

accepted among the learned.

He apparently went to Brittany to spend the winter of–,hoping to

complete that project. As we know now, that never happened. While he

was with his family in Brittany, he became godfather to his brother Pierre’s

child at Elven, in Morbihan (January), and he was still there at the

end of March when Balzac wrote to him.Twenty years later, he reflected