 Similarly, in a letter to Voltaire five years later (February 19 1758), he wrote clearly that “The reign of mathematics has ended. Tastes have changed, in favor of natural history and letters”. Diderot is opposing the new “taste” and interest for a set of preoccupations including two forms of “life science” (natural history and “experimental physics”) to the traditional prestige of mathematical science. In these passages, he is also squarely locating his materialist preoccupations within the former.