Marx versus Engels

Karl Marx and Friedrich Engels held contrasting views with regard to infinitesimals. The former referred to them as "chimeras" while the latter praised them as a "triumph". The first editor of Marx's mathematical manuscripts, Emil Julius Gumbel, was not even mentioned in either the first (1933) or the second (1968) Soviet editions of Marx's mathematical manuscripts. Editor Yanovskaya is mentioned in both. Marx's studies of the calculus seem to have started with a book by Sauri. The interesting thing about Sauri's book is its influence on Marx, who explained the derivation of the tangent to a parabola to Engels in the 1860s using infinitesimals and the infinitesimal "characteristic triangle" that Leibniz learned from Pascal. Later, Marx began studying the book by Boucharlat which mostly avoided infinitesimals. This influenced Marx to develop a negative attitude toward infinitesimals, and to describe them as "chimeras". It is interesting to note that Engels was far more positive about infinitesimals, and described them as a "triumph" of the human imagination. Note that the first editor of Marx's Mathematical Manuscripts was Emil Julius Gumbel. Gumbel is not mentioned in either the first (1933) or the second (1966) Soviet edition of Marx's mathematical manuscripts. The name of editor Yanovskaya appears throughout. See 26a.