 Philosophers have also discussed classification at the interface of biology and chemistry. Goodwin (2011) has argued that structure is fundamental and sufficient for classification of biomolecules, such as proteins. Tobin (2010a) and Slater (2009) appeal to developments in the relationship between protein structure and function in a number of cases such as moonlighting proteins, intrinsically unstructured proteins, and enzymes with multiple structural variants. They claim that the path from structure to function in not straightforward and so undermines the fundamental individuating role of structure in protein classification. Slater (2009) takes these developments in the practice to constitute an argument in favour of macromolecular pluralism. Goodwin (2011) claims that these developments do not undermine the fundamental role of structure in protein classification, but instead suggest a more nuanced understanding of this role. (Goodwin, 2011: p. 534) In a similar vein, Tahko (2020) argues that biochemical kinds pose a challenge for ontological reductionism and for microstructuralism, which have led some to motivate a dual theory of chemical and biological kinds and others to argue for pluralism about natural kinds. Tahko argues that the main challenge is multiple realization, which he nevertheless, thinks can be addressed. The upshot is that there are reasonable prospects for ontological reductionism about biochemical kinds, which in his view corroborates natural kind monism. Thus, even if there are indispensable classificatory practices at the higher level, this need not entail pluralism about biochemical kinds.