Descartes: A Biography

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

Retreat and Defence (–) 

representative of a wider readership these comments may have been. The

publisher sold relatively few copies during the first two years, which made

it unlikely that it would be reissued soon afterward.

AReclusive Life

Descartes’ life during the period–was dominated by research and

letter writing. Between Mayand December,hewrote approxi-

mately two hundred pages of detailed letters in reply to the French math-

ematicians. Apart from this work, he wrote almost weekly letters in reply

to an extraordinary array of disparate queries from Mersenne. Each letter

from Mersenne typically asked for explanations of a long list of itemized

phenomena that ranged from the limited efficiency of water pumps to

optical phenomena and musical theory. Descartes then took these letters,

sometimes more than one at a time, and answered the queries in order,

using the same numbering system for his replies as Mersenne had used

forhis questions. Evidently, he could not give as much time to each query

as it may have deserved, although he tried valiantly to reply to all queries

bywriting even on Christmas Day of, when he offered this gen-

eral excuse for his replies. ‘Having sometimes to reply to you concerning

twenty or thirty different things in one evening, it is impossible for me to

give a lot of thought to each one’ (ii.). In addition to such extensive cor-

respondence, he continued to conduct anatomical experiments, including

vivisections. ‘This is an exercise that I have often performed during the

past eleven years and I think there is hardly any physician who has made

such detailed observations as I have.’

One might expect that Descartes spent much of his time reading while

in seclusion in Holland. However, he claims to have had only about ‘half a

dozen books’ in his house, and he was too busy to take the time required to

read most of those that were sent by various correspondents.Among the

authors that he declined to read or, despite their merits, could not find time

to read were Campanella, Beaugrand, Galileo, Roberval, Stevin, Horten-

sius, Herbert, and Bouillau.When the controversy with the French

mathematicians showed no signs of abating, he tried to cut it short by

denying that he had any further interest in geometry. In fact, he claimed

to have given up studying geometry as early as.‘Youknowthat it is

already fifteen years since I professed to give up geometry’ (ii.).This

means that his original work in that discipline, especially his contribution