Salient theories in the fossil debate in the early Royal Society: the influence of Johann Van Helmont

In the late seventeenth century, several luminaries in the early Royal Society argued over the origins of fossils. Past historiography, particularly the work of Martin Rudwick and Rhoda Rappaport, has sketched the broad outline of the controversy. The naturalist John Ray (1627-1705) and microscopist Robert Hooke (1635-1703) argued that fossils were remnants of past animal and plant life, although they differed in opinion of “how fossil-bearing strata had been deposited.” Since the Christian creed taught that all species were created in Genesis, any ideas of species becoming extinct were considered heterodox. On the other hand, Robert Plot (1640-1696), secretary of the Royal Society and keeper of the Ashmolean Museum, and Dr. Martin Lister (1639-1712), the first arachnologist and conchologist, stated that fossils were not always remains of living creatures, but could be created spontaneously by nature as part of her inherent generative powers. Little work has been done examining Lister's and Plot's explanation of these generative powers and “seeds” which this article will show were all differing adaptations of, or reactions, to Belgian physician Johann Van Helmont's (1579-1644) theories in saline chymistry. Antonio Clericuzio has noted that several members of the Royal Society in the late seventeenth century developed and transformed Van Helmont's chemistry by interpreting its main notions - that is, semina, ferments, spirits and the Alkahest - in terms of corpuscles, particularly saline corpuscles endowed with a plastic formative power.There has been no analysis, however, to what extent these interpretations affected thefossil controversy over their formation, composition and nature. This paper will thuselucidate the disagreements amongst Lister and Plot about the fossilisation process,placing their work in the larger context of seventeenth-century natural history andHelmontian chymistry. Their debate over the origin of crinoid or sea lily fossils will be utilised as a case study to elucidate the fossil controversy and its chymical basis.