Descartes: A Biography

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Magic, Mathematics, and Mechanics 

alliance between Charles I and the unfortunate residents of La Rochelle,

and precipitated the siege that lasted for more than a year. Buckingham

sailed home in October, and Charles I subsequently promised assis-

tance to the besieged city on a number of occasions, in response to requests

from La Rochelle. When the siege concluded, onOctober, approx-

imately,of the city’s citizens had died of hunger and associated

sicknesses. The triumphant royal army entered the city, and Richelieu

celebrated a High Mass in the cathedral, with a Te Deum in thanksgiving

fortheir victory. It would help us to understand Descartes’ political alle-

giance if he were found to have supported the siege, although those who

place him at La Rochelle suggest that he merely visited – as many others

did, almost like tourists – to study the architecture of the famous dyke

erected around the city during the siege.

TheRules

Descartes’ writing during this period shows the indecisive search for a new

method that was reflected in the wide range of authors he consulted, his

interest in optics, and the first signs of an awareness that mathematics was

only one science among many. TheRuleswere drafted and redrafted at var-

ious times during the decade–and were then abandoned. However,

Descartes kept the text and carried it with him throughout his travels and

frequent changes of residence until his death, in Stockholm, more than

two decades later. The inventory of his library includes a reference to

‘nine notebooks, bound together, containing part of aTreatise of Clear and

Useful Rules for Guiding the Mind in Searching for the Truth’ (x.).This

manuscript was passed to Clerselier, who deferred doing anything with it

until he had published other material from Descartes’ manuscripts. Mean-

time, he showed it to Arnauld and Nicole, who included parts of Rule

inThe Art of Thinking(), and he allowed Leibniz to have a copy made

(inor), before passing it on to Jean-Baptiste Legrand. After

the latter’s death in, the original manuscript disappeared. Before its

final disappearance, however, a Dutch translation appeared in, and

the Latin source of that translation was published for the first time in its

original language in.

It has been recognized for many years that the surviving text of the

Rulescannot disguise the extent to which it was edited and frequently

recast before Descartes abandoned hope of completing it. It was originally