Vere Chappell has pointed out that it is not clear whether Locke has a well-developed ontology or even whether he is entitled to have one.2 Nevertheless, it is clear that Locke believes that there are organisms, and it is clear that he thinks that there are substances. But does he believe that organisms are substances? There are certainly parts of the Essay in which Locke seems unequivocally to state that organisms are substances. For instance, in 2.23.3 Locke uses men and horses as examples of substances. In Locke’s most explicit the account of abstraction, given in 3.3.7-9, organism [vivens] is treated as a sub-species of body and body as a sub-species of substance; so, by transitivity, organism is a kind of substance. Finally, in his discussion of essences in 3.6, Locke uses all of the following organisms as examples of substances: horses, mules, men, sheep, goats, plants, drills, changelings, asses, bulls, cats, and rats. This textual evidence would seem to settle the matter about the ontological status of organisms. However, there are other parts of the Essay in which the ontological status of organisms is less clear, to say the least. In fact, there are texts in which Locke seems to state (or at least to be committed to the..