Descartes: A Biography

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

 Descartes: A Biography

most general types of reality that were accepted by scholastics, namely, a

substance or a property. Worse still, if Pascal were so keen to accept only

what was observable, a vacuum should be rejected because it is invisible,

inaudible, and so on.Despite these metaphysical objections, however,

Noel acknowledged the significance of Pascal’s experimental results. He ̈

conceded that he had learned much from them and had even modified his

ownscholastic views accordingly

Descartes, for his part, had returned to Holland before the publication of

Pascal’sNew Experiments.However, the author sent him a copy, and Huy-

gens as usual acted as a postal intermediary. When forwarding the book to

Egmond, in November, Huygens advised that Descartes say noth-

ing in public about the disagreement with Pascal until ‘the young author

has published his views about the whole matter’.Descartes accepted

that Pascal’s ‘booklet’ was, on his own account, merely an abridged ver-

sion of what he promised to publish later. However, this did not prevent

Descartes from expressing a provisional evaluation, even while hoping to

see the fuller presentation in the near future. ‘It seems to me that the

young man who wrote this booklet has the vacuum a bit too much in his

head and that he is in a great hurry. I wish that he had already published

the volume that he promised, so that his arguments could be examined.

Unless I am mistaken, they will be as unconvincing as what he has tried

to prove.’

The following week he told Mersenne that Pascal had sent him a copy

of his publication, in which ‘he seems as if he wishes to attack my subtle

matter.’As usual, Descartes reserved the right, at some unspecified

‘time and place, to explain everything that I consider relevant to defend

myself’ (v.). He asked Mersenne if he knew whether Pascal had done the

experiment that they had talked about in late September (i.e., the Puy-de-

Dome experiment). While waiting for news about that, he suggested thatˆ

the Minim friar could assist by doing a joint experiment, for which he sent

instructions. Descartes had noticed that the height of the mercury column

varied with weather conditions, and he made two long strips of paper,

about two and a half feet long, on which he had marked exactly similar

intervals. He sent one of them to Mersenne in Paris, so that while Pascal was

checking changes in the height of the mercury column at different heights

above sea level, Mersenne and Descartes could do a parallel experiment to

see if the mercury level varied with changes in weather conditions at the

same place.