Marx-Engels Correspondence 1882
Source: Marx’s Mathematical Manuscripts, New Park Publications, 1983;
Transcribed: by Andy Blunden.
... Sam, as you saw immediately, criticises the analytical method applied by me by just pushing it aside, and instead busies himself with the geometrical application, about which I said not one word. In the same way, I could get rid of the development of the proper so-called differential method — beginning with the mystical method of Newton and Leibnitz, then going on to the rationalistic method of d'Alembert and Euler, and finishing with the strictly algebraic method of Lagrange (which, however, always begins from the same original basic outlook as Newton — Leibnitz) — I could get rid of this whole historical development of analysis by saying that practically nothing essential has changed in the geometrical application of the differential calculus, i.e. in the geometrical representation.
The sun is now shining, so the moment for going for a walk has come, so no more pro nunc of mathematics, but I'll come back later to the different methods occasionally in detail ...