Peter Anstey wrote this book while he and Lawrence Principe were editing the Clarendon volume of Locke’s Works on natural philosophy and medicine. Thus, it is the product of an enormous amount of textual and archival work. Anstey uses his vast knowledge of Locke’s natural philosophy to argue for four main claims. First, Locke gave experimental natural philosophy higher epistemic status than speculative systems (including, importantly, “the mechanical philosophy”). Second, Locke thought that constructing Baconian natural histories was the best way to do experimental natural philosophy. Third, Locke did speculate, especially about corpuscularianism, chymistry, and chymical medicine. Fourth, by the 1690s, Locke gave the Newtonian, mathematical method a key role in natural philosophy. Very roughly, chapters 1–5 argue for the first two claims, chapter 9 argues for the third claim, and chapters 6–8 argue for the last one.
All four conclusions are well defended. I will leave it up to the reader to decide how surprising they are. I do think Anstey oversells the novelty of his interpretation at certain points. One clear case is his argument that Locke was no hypothetico-deductivist, an aspect of his claim that Locke was suspicious of speculation. But almost all readers will find some of Anstey’s conclusions new and challenging.
Sketching Anstey’s argument for the claim that Locke thought that natural philosophy was best done by constructing Baconian natural histories gives the flavor of much of the book. He provides an inventory of all of Locke’s published and unpublished references to Bacon. He carefully explains how Baconian natural histories work. He sketches some of Boyle’s natural histories and describes how Locke was involved in their construction, dissemination, and reception. He suggests that Locke’s use of travel literature can be seen as natural history. And finally, he shows that Locke offered natural histories of diseases.
Chapters 10 and 11, where Anstey argues that Locke is a species realist, will probably be the most controversial part of the book; I also thought this was the weakest part. Anstey argues—against the common view that Lockean real essences are relativized to nominal essences—that nominal essences are clusters of ideas caused by naturally occurring clusters of properties and that properties clusters “have their foundation in the real essences of corpuscular structures of [members of] objectively existing kinds” (213; cf. 214).
Anstey’s argument begins by trying to shift the burden of proof onto his opponent:
If, in order to account for the generation of species, Locke consistently posits the existence of entities [seminal principles or seeds], many of which have never been observed, yet which have powers that are difficult to explain, it would be bold indeed for someone to claim that Locke denied the existence of species in nature.(204) [End Page 296]
I do not see how this burden-shifting is supposed to work. Everyone grants that individuals are generated by seeds; the key is how Anstey conceives of the relationship between the individuals, their seeds, and the species. Earlier, he quotes Locke saying that “in vegetables we finde that severall sorts come from the seeds of one & the same individual as much different species as those that are allowed to be soe by philosophers” (200). Anstey thinks this implies “that phenotypic characteristics are neither necessary nor sufficient to guarantee species membership” (200). But this imports an awful lot into the text. I do not see Locke distinguishing shared phenotype from species membership; the natural reading of the passage is that one cabbage can produce offspring belonging to two different species.
Anstey has further arguments against the relativized real essence interpretation—five of them, in fact. I found the five arguments jointly uncompelling, and as individuals they range from weak to misplaced. For instance, Anstey says that on the relativized real essence view, Locke’s claim that we are ignorant of real essences “would make no sense” (216), but this relies on a misunderstanding of the view. He says that the relativized real essence view fits badly with Locke’s general...