Descartes and Blaise Pascal

TO GILBERTE PASCAL PÉRIER

Paris Wednesday, September 25, 1647

Dearest Sister, I have delayed writing to you because I wanted to inform you about everything related to the meeting between Monsieur Descartes and our brother.1 Yesterday I did not have time to write and tell you that Monsieur Habert came here on Sunday night. Monsieur de Montigny from Brittany accompanied him.2 Monsieur de Montigny came to tell me that his close friend Monsieur Descartes had expressed a strong desire to meet our brother.

(He wasn’t able to speak with our brother, who was in church at the time.) Monsieur Descartes had the greatest esteem for our father and our brother because of their achievements, which everyone has been talking about. To satisfy his desire, he wanted to come meet our brother the next day at nine o’clock in the morning if that would not be too inconvenient for him. (He knew that our brother was ailing.) I found it difficult to respond to Monsieur de Montigny’s proposal for this meeting because I knew that our brother found it difficult to work or speak for any length of time, especially in the morning. Nonetheless, I did not think it would be right to refuse to have such a meeting. We agreed that Descartes would arrive at ten thirty the next day.

The next day Monsieur Descartes arrived at the time we had agreed upon. He was accompanied by Monsieur Habert, Monsieur de Montigny, a young cleric I did not recognize, the son of Monsieur de Montigny, and several other young boys. Monsieur de Roberval,3 whom my brother had notified beforehand, was already here. After some polite comments, they began to discuss the calculating machine. Everyone marveled at it as Monsieur Roberval demonstrated its use.

They then began to discuss the problem of the vacuum. Monsieur Descartes became especially serious on this topic. The others explained a recent experiment to him. They asked him what he thought entered into the space of the emptied tube. He replied that it was his “subtle matter.” My brother responded to this theory as best he could. Monsieur de Roberval thought my brother was having difficulty expressing his ideas. He took on Monsieur Descartes with not a little passion, although he remained civil. Monsieur Descartes responded quite bitterly that he would talk with my brother as long as my brother wanted to, because my brother speaks reasonably, but that he would not continue to talk with Monsieur de Roberval, because the latter was too prejudiced against him.

Having said this, Descartes looked at his watch and saw that it was noon. He stood up because he had a dinner engagement in the Faubourg Saint-Germain. Monsieur de Roberval also had an appointment in the same neighborhood. So Monsieur Descartes walked him over to a carriage. The two of them were then alone. They seemed to be joking with each other but there also seemed to be an edge to their laughter. After he returned from dinner to meet Monsieur d’Alibray,4 Monsieur de Roberval confirmed this impression for us.

I forgot to tell you that upset by the little success he had had in the discussion that morning, Monsieur Descartes promised my brother that he would come to see him again at eight o’clock the next morning. When we told Monsieur d’Alibray about this new meeting the evening before, he wanted to be there. He tried to bring Monsieur Lepailleur with him.5 My brother had asked for him to be invited on his behalf. But he was too lazy to come over and visit, although both he and Monsieur d’Alibray had planned to have dinner not very far from here.

In part Monsieur Descartes came back to examine my brother and to give him some advice about his illness. But he actually had very little to say about it. He only counseled my brother to remain in bed every day until he was no longer able to stay abed any longer and that he drink some strong bouillon. They spoke about many other things because they stayed together until eleven o’clock. But I do not know what they discussed because I was not present yesterday.
I was not able to know this because we were busy all day yesterday trying to get my brother to take his first bath. He said that the bath gave him a small headache but that is because he made it too hot.

I think that the bleeding of his foot on Saturday evening did him a great deal of good because on Monday he was able to speak a long time with Monsieur Descartes in the morning and with Monsieur de Roberval in the afternoon. He had a lengthy dispute with Monsieur de Roberval over many issues treating more of theology than of physics.

Nonetheless, later that night he did not have any other pain other than some night sweat and some insomnia. He did not have the headaches I would have expected after such an effort.
Tell Monsieur Ausoult that my brother wrote a letter to Père Mersenne the other day to ask him about the reasons why Descartes opposed the theory of the column of air. The response was poorly written because he had cut an artery in his right arm during a bleeding. This might cripple him. However, I read that it was not Descartes who opposed this theory. On the contrary, it was Roberval who strongly opposed it. In this letter my brother also expressed his delight in seeing Monsieur Descartes and in seeing Descartes’s admiration for his machine. But we should consider all that a simple formula of politeness.

Farewell, beloved sister.

I remain your most humble and obedient servant, J. Pascal.

Source
The Other Pascals The Philosophy of Jacqueline Pascal, Gilberte Pascal Périer, and Marguerite Périer

John J . Conley , S .J .