The Lost Journal of Descartes

As far as anyone knows, the journal Descartes kept in the winter of 1619 no longer exists. In La Vie de Monsieur Descartes, Adrien Baillet describes a period of solitude leading up to the discovery of ‘the foundations of a miraculous science’ - mirabilis scientiae fundamenta.

From Baillet, Livre second, chapitre premier, Paris, 1691:

In the new ardor of his resolutions, he undertook the execution of the first part of his designs, which consisted only in destroying. It was apparently the easier of the two. But he soon realized that it was not as easy for a man to undo his prejudices, as it was for him to burn down his own house.

In 1676, Leibniz studies Descartes journal. It is 22 years after Leibniz’s own experience of revelation:

Year of Grace 1654

Monday, the 23^rd of November, day of Saint Clement, pope and martyr, and others in the catalogue of martyrs. Eve of Saint Chrysogone, martyr and others. From half past 10 in the evening till half past midnight.

Flame
“God of Abraham, God of Isaac, God of Jacob” not of the philosophers or scholars.
Certainty, Certainty, Feeling, Joy, Peace.
God of Jesus Christ.
Deum meum et Deum vestrum…

After Leibniz’s death in 1716, his notes are deposited in the Royal Library at the Hague. Leibniz’s notes are lost. Our knowledge of Descartes’s notebook depends on the work of Baillet and on the notes copied from Leibniz by the Count Alexandre Foucher de Careil in 1859.

The cover of the notebook is marked with the date, 1 January 1619. Its contents are as follows:

1. Parnassus – mathematical considerations
2. Olympica
3. (untitled) “considerations on the sciences”
4. (untitled) “algebra”
5. Democritica
6. Experimenta
7. Preambula