"Differential calculus...is consequently a basic and real means of exploration of the reality of existence."

- Deleuze, from seminar of 22 April 1980. 

"We must not see mathematical metaphors in all these expressions such as 'singular and distinctive points' or 'adjunct fields'...These are categories of of the dialectical Idea, extensions of the differential calculus (mathesis universalis)...corresponding to the Idea in all its domains."

- Difference and Repetition, 190.

Via Daniel W. Smith.