Mind, memory and history: How classifications are shaped by and through time, and some consequences

Understanding the history of systematics bears on contemporary issues such as the distinction between classifications and systems, the belief that ‘natural’ classifications reflect the progressive refinement of our ideas of relationships, and the dubious reputation acquired by systematics. Here I emphasize the extent to which ‘mind’ shapes classifications. I show that groups in biological classifications often have six or fewer members, in line with the number of things that humans can conveniently memorize together. Concerns about memorization are evident in the work of systematists like Tournefort, Linnaeus, and Antoine-Laurent de Jussieu, and the whole hierarchy of George Bentham's and J. D. Hooker's great Genera plantarum is structured by such concerns. An analytical element in Jussieu's work was emphasized by Cuvier and others, and the hierarchy of their classifications reflects more directly aspects of nature as they understood it, although concerns about memorisation remain evident. Linking an understanding of what classifications can represent to the ideas the makers of classifications had about nature makes it clear that classifications are rarely rigid class hierarchies, but are often more like systems. Historically, the synthetic approach, discussed here, tends to lead to systems, the analytical approach, to ‘classifications’. We must remember that systematists’ work is evaluated by other scientists, and by society at large. The confusion evident in systematics simply confirmed the negative perceptions that many people in the nineteenth century had of naturalists, botanists and zoologists, perceptions that persist today. Zoologica Scripta itself, and the Journal of Natural History, which under this title is about the same age, reflect part of this history. I conclude by emphasizing (1) if systems or classifications in the nineteenth century reflect ‘nature’, it is a nature very different from that we understand today, and (2) the extent and the persistence of the opposition between the synthetic and anaytical approaches.