ABSTRACT
This chapter presents some 19th and early 20th century alternatives to the view of natural kinds and chemical elements as fixed by essential properties. I briefly describe John Stuart Mill’s account of natural kinds, as well as efforts by his commenters to reconcile that account with Mill’s claims about causation. I argue that William Bateson’s analogies between the units of genetics and chemical elements are best understood as analogies to theoretical entities in the history and practice of chemistry. Bateson did not intend that the units of heredity answer to material units that behave in ways analogous to material atoms. His point was that biologists of his day should postulate a theoretical entity, basic to the science, as elements once were to chemistry. Bateson matter-of-factly asserted that species fixity was first established as a scientific hypothesis in the 18th century and took this hypothesis to be an important scientific advance. I support this claim via history of biology texts written in the early 20th century that straightforwardly report that Linnaeus’ two most important contributions to biology were binomial nomenclature and the concept of fixed species. Chemical elements were reinterpreted in the early 19th century and replaced by electrons, neutrons, and protons as basic units, recognizing that elements can in fact transmute. Comparing characters, genes, and species to chemical elements predicted that scientific progress would be made by positing theoretical entities that would later be revised within a new theoretical framework.
