Strings, Physies, and Hogs Bristles

It is often claimed that classification, on Locke’s view, proceeds by attending to the similarities between things,1 and it is widely argued that nothing about the sensible similarities between things determines how we are to sort them, in which case sorting substances at the phenomenal level must be arbitrary. However, acquaintance with the “internal” or hidden qualities of substances might yet reveal objective boundaries. Citing what I refer to as the Watch passage [henceforth Watches], many commentators claim that classification at the microphysical level must also be arbitrary. They conclude that sorting is arbitrary at any level of description. I refer to this as the standard reading of Locke on classification. In this paper I argue that Locke does not claim that sorting is arbitrary, either at the phenomenal level, or at the microphysical level. First, Locke does not claim in Watches that sorting is arbitrary at the microphysical level. The existence or nonexistence of objective boundaries at the microphysical level is not Watches’ topic and the passage is in fact silent on that question. Here, the standard reading mistakes a claim about the nature of the task of locating “specific differences” for a claim about the nature of the task of classification. This diagnosis proves instructive, for I argue that a similar conflation underwrites the standard reading’s claim that sorting at the phenomenal level must be arbitrary. Far from arbitrarily choosing how to sort things in terms of their phenomenal similarities, Locke thought that the mind simply follows nature’s lead. This characterization of the mind’s activity, I go on to argue, accords well with Locke’s claim that species are the workmanship of the understanding.