We might almost call it the Cartesian period for, though Descartes was dead, it was in these years that Cartesianism performed its task and transformed human thought.
When we speak of Cartesianism we do not mean the metaphysical system of the master, or any of his particular views such as that of innate ideas.

We mean the general principles, which were to leave an abiding impression on the texture of thought: the supremacy of reason over authority, the stability of the laws of Nature, rigorous standards of proof.

Fontenelle was far from accepting all the views of Descartes, whom he does not scruple to criticise; but he was a true Cartesian in the sense that he was deeply imbued with these principles, which generated, to use an expression of his own, "des especes de rebelles, qui conspiraient contre l'ignorance et les prejuges dominants." [Footnote: Eloge de M.Lemery.] And of all these rebels against ruling prejudices he probably did more than any single man to exhibit the consequences of the Cartesian ideas and drive them home.
The Plurality of Worlds was a contribution to the task of transforming thought and abolishing ancient error; but the History of Oracles which appeared in the following year was more characteristic.

It was a free adaptation of an unreadable Latin treatise by a Dutchman, which in Fontenelle's skilful hands becomes a vehicle for applying Cartesian solvents to theological authority.

The thesis is that the Greek oracles were a sacerdotal imposture, and not, as ecclesiastical tradition said, the work of evil spirits, who were stricken silent at the death of Jesus Christ.