Engels discusses the dialectics of quantity and quality in chapter 12 of part one of Anti-Dühring. In this chapter Engels takes on Dühring anti-dialectical approach to philosophy. Not having understood Hegel, Dühring thinks that since a contradiction appears to be absurd (how can you have A and not-A at the same time?) there can be no contradictions in reality. Engels sets himself the task of clearing up Dühring confusions.
Examples of contradictions in nature, according to Engels are, for example, MOTION, where a body is "in one and the same place and also not in it" and LIFE, where a being "is at each moment itself and yet something else." This, I must admit, sounds a bit like Sartre's existentialism and is perhaps for our time a bit more metaphorical than scientific. What Engels means by motion being a contradiction is perhaps best expressed in the following quote from the article "Motion" in the Great Soviet Encyclopedia.
"The contradictory nature of motion consists in the unbroken unity of two opposing factors --- changeability and stability, motion and rest. in fact, the concept of change makes sense only in connection with the idea of a relatively stable, continuously fixed state. This very change, however, is at the same time also a fixed state, which continues and maintains itself; that is, it also possesses stability. In this contradictory unity of changeability and stability the leading role is played by changeability, for everything new in the world first appears by means of it, whereas stability and rest merely fix what has been attained through this process" (from the article by V.I. Sviderskii).
Dühring also makes fun of Das Kapital because of Marx's use of dialectics.
Marx's book, Dühring writes , is an example of the "absence of natural and intelligible logic" resulting in "dialectical frills and mazes and conceptual arabesques." As an example of Dühring complete misunderstanding of Marx's Das Kapital, Engels focuses on his attack on Marx's use of the dialectical notion that quantitative changes bring about qualitative changes.
Here is what Dühring himself has to say about this: "What a comical effect is produced by the reference to the confused, hazy Hegelian notion that quantity changes into quality, and that therefore an advance, when it reaches a certain size, becomes capital by this quantitative increase alone!"
By adding the word "alone" Dühring falsifies both the Hegelian law and Marx's understanding of it. This is what Marx wrote in Vol. 1 of Das Kapital when he discussed how a sum of exchange values, after reaching a certain quantity could become capital. "Here, as in natural science, IS SHOWN the correctness of the law discovered by Hegel (in his LOGIC) that merely quantitative differences beyond a certain point pass into qualitative changes."
Engels says Marx held a sum of exchange values can become capital only when it reaches a definite minimum size, depending on the conditions, "this fact is a PROOF OF THE CORRECTNESS of the Hegelian law." Dühring says Marx held BECAUSE quantity changes in to quality THEREFORE at a certain sum exchange value will become capital. The part about "depending on the conditions" is left out so "the very opposite" of what Marx meant [ i.e., an effect is taken as a cause] is put forth as his meaning. This is typical of what Dühring calls his "philosophy of reality." And, Engels adds, "he has the cheek to describe as COMIC the nonsense which he himself has fabricated."
One of the most obvious examples of the dialectical law under discussion is that of H2O. Water in the solid state becomes a liquid with the quantitative addition of heat and with even more heat the liquid state qualitatively changes into a gas.
Engels also points out that all of Part IV of Das Kapital (where Marx discusses the production of relative surplus value and modern industry, etc.) "deals with innumerable cases in which quantitative change alters the quality, and also qualitative changes alter the quantity, ot the things under consideration." The molecular theory of modern [1880s] chemistry is also based on this law.
Thus, Engels maintains, in both the social world and the natural world around us we "can see how 'quantity changes into quality,'and this allegedly confused, hazy Hegelian notion appears in so to speak corporeal form in things and processes--- and no one but Herr Dühring is confused and befogged by it."
Next we will deal with the last chapter on Engels' discussion of philosophy in Anti-Dühring-- the chapter on the negation of the negation.