Descartes: A Biography

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Retreat and Defence (–) 

discussed tangents to curves, Descartes did not realize that it had been

written about eight years previously and that it was therefore not repre-

sentative of Fermat’s most recent work.Descartes replied: ‘I would be

happy to say nothing about the text that you sent me, because I could

not say anything about it that would be favourable to whoever wrote it’

(i.).The controversy was exacerbated when two of Fermat’s sup-

porters in Paris,Etienne Pascal and Roberval, joined the fray in sup- ́

port of the Toulouse parliamentarian.Etienne Pascal ( ́ –), the

father of the more famous Blaise (with whom Descartes would also cross

swords later), had sold his tax-collecting office at Rouen inand moved

to Paris, where he was associated temporarily with the Mersenne circle.

Descartes assumed – mistakenly, it seems – that these two ‘defenders’ of

Fermathad joined the discussion as uncritical friends of his opponent

and that their opinions were thus compromised.He puffed, at a great

distance from local events in Paris and without knowing the situation: ‘I

despise those who get involved in slandering myGeometrywithout under-

standing it’ (ii.).

While Descartes described the dispute in terms of a combat and

demoted Roberval and Pascal to Fermat’s ‘seconds’ in the protracted duel,

he simultaneously excused himself from being responsible for the animos-

ity between them.‘If there is any special animosity between him [Fermat]

and me, as they [Roberval and Pascal] claim, it is entirely on his side. For,

from my point of view, I have no basis to complain against those who wish

to challenge me in a combat in which one can often be vanquished without

infamy’ (ii.). Descartes even suspected his opponents of making minor

butimportant changes in the disputed texts, and advised his own support-

ers to protect against this by holding onto the original manuscripts and

giving only copies to critics.This distrust is matched by the uniformly

sharp and uncomplimentary comments he made about all those who dis-

agreed with him throughout the dispute. He thought that Beaugrand’s

Geostaticswas ‘so impertinent, ridiculous and despicable that I am sur-

prised that any honest person has ever taken the trouble to read it’.He

described the Calvinist ministers in the United Provinces as ‘mute like fish’

in response to his book, and he claimed that Martinus Hortensius (–

) was ‘not only very ignorant, but was a very black and malicious soul’

who feigned friendship with Descartes while simultaneously slandering

him in secret.Roberval did little to calm the controversy by writing that

Descartes had evidently failed to understand Fermat’s method. According