Appendix: Notes to Anti-Dühring¶
This appendix contains three substantial notes written by Engels in 1877-78, originally intended as supplements to the first (Philosophy) section of Anti-Dühring. The first note, (a), explores the real-world prototypes of mathematical infinity, using examples from molecular physics, chemistry, and astronomy to argue that nature operates with differentials and integrals analogous to those in calculus. The second, (b), critically examines the "mechanical conception of nature," engaging with Kekulé's definitions of mechanics, physics, and chemistry, and warning against reducing all qualitative change to mere quantitative displacement. The third, (c), is a brief critique of Nägeli's claims about the unknowability of qualitative differences. The notes are closely connected to themes in Engels' Dialectics of Nature and reference Hegel, Haeckel, and contemporary scientific debates.