 Complete the following phrase:  Deleuze passed the agrégation in philosophy in 1948, and taught at various lycées Amiens, Orléans, Louis le Grand until 1957, when he took up a position at the University of Paris. In 1953, he published his first monograph, Empiricism and Subjectivity, on David Hume. This monograph was based on his 1947 DES  thesis, roughly equivalent to an M.A. thesis, which was conducted under the direction of Jean Hyppolite and Georges Canguilhem. From 1960 to 1964, he held a position at the Centre National de Recherche Scientifique. During this time he published the seminal Nietzsche and Philosophy 1962 and befriended Michel Foucault. From 1964 to 1969, he was a professor at the University of Lyon. In 1968, Deleuze defended his dissertations amid the ongoing 