Chemistry¶
Core Argument¶
This chapter digest presents Engels’s dialectical-materialist reading of the history and theoretical foundations of chemistry, arguing that the science only became genuinely modern when it abandoned qualitative, pre-scientific notions for a quantitative, atomistic framework grounded in the transformation of quantity into quality.
Engels opens with a polemic against the antiquated view, prevalent until Lavoisier, that chemical affinity resulted from two bodies each containing a common third substance—a notion he dismisses as childish and drawn from Hermann Kopp’s history of chemical development. He then attacks a persistent methodological hindrance: the use of percentage composition to express chemical compounds. This convenient but superficial technique, Engels claims, actively obstructed the discovery of the laws of constant and multiple proportions, delaying the emergence of a truly scientific chemistry for a considerable period.
The core theoretical claim is that a new epoch in chemistry begins with atomistics, and Engels is emphatic that Antoine Lavoisier is not the father of modern chemistry—that honour belongs to John Dalton. This atomistic turn is paralleled in physics by the molecular theory and the discovery of the transformation of forms of motion. Crucially, Engels distinguishes the new atomistics from all previous atomistic doctrines by insisting that matter is not merely discrete. Instead, the discrete parts at various stages—ether atoms, chemical atoms, masses, heavenly bodies—are “nodal points” that determine the qualitative modes of existence of matter in general, extending even to weightlessness and repulsion. This is a direct application of Hegelian dialectics to natural science.
Engels provides the simplest example of the transformation of quantity into quality: oxygen and ozone, where a ratio of 2:3 atoms produces entirely different properties, including odour. He generalises this to all allotropic bodies, explaining them solely by differences in the number of atoms in the molecule. Finally, he addresses nomenclature, arguing that in organic chemistry a body’s significance and name are no longer determined merely by its composition but by its position within a homologous series. Old names, he insists, become obstacles to understanding and must be replaced by series names such as “paraffins.” The chapter thus functions as a sustained argument for a dialectical materialist epistemology in chemistry, opposing both pre-Daltonian empiricism and any idealist or metaphysical resistance to the quantitative determination of qualitative difference.