Descartes: A Biography

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

Once More into Battle 

Descartes spent the next six months in the company of Picot, who

accompanied him to Rennes, to Poitou, and then back to Egmond. His

financial affairs were concluded at Rennes onJuly, after which the

two companions journeyed to Poitou and then returned to Paris through

Touraine. Baillet recounts the story of Descartes accepting the hospitality

of a Mr. de Crenan, who was so happy to have such a famous visitor that he

wanted to share his company with his friends and neighbours. Descartes,

however, remained aloof, was never seen before midday, and even when

he should have respected his host’s expectations for the evening, went

walking alone and left Picot to entertain the invited guests.

Picot and Descartes returned to Paris toward the beginning of Septem-

ber. There they found that Mersenne had fallen ill in late August, and his

condition was exacerbated by an incompetent surgeon who cut an artery in

his arm while attempting to bleed him. Mersenne was concerned that his

arm would become gangrenous, a danger that subsided only the follow-

ing month.However, his recovery was relatively short-lived, because he

died the following year in Paris. Mydorge, unfortunately, had died while

Descartes was in Brittany, about two weeks before his return to Paris.

The most memorable person to meet Descartes on the occasion of

this visit, however, was Blaise Pascal, the relatively young son ofEtienne ́

Pascal, who had supported Fermat’s critique of Descartes’Geometryten

years earlier.

Descartes and Pascal

Blaise Pascal (–) was only twenty-four years old, and already in

poor health, when Descartes visited him at his home in Paris onand

September.Pascal is usually remembered today as the author

of famous, randomly collected jottings in draft form that he prepared in

defence of his religious faith and that were published posthumously under

the titlePens ́ees,orasthe scourge of the Jesuits in a series ofProvincial

Letters that were published anonymously in – in defence of

Jansenism. However, when Descartes came to visit Paris in, the

young Pascal had acquired a modest reputation primarily as a mathemati-

cian, as the inventor of a mechanical calculating machine, and as someone

who had recently become interested in pneumatics.

Pascal’s younger sister, Jacqueline – who later became a nun at Port

Royal – wrote to her older sister, Gilberte, with a detailed description of