ARTICLE MECHANISM,RESEMBLANCE AND SECONDARY QUALITIES:FROM DESCARTES TO LOCKE* Keith Allen the Democritick and Epicurean Atheists . . . acknowledge no other Modes of Matter or Body, but only more or less Magnitude of Parts, Figure, Site, Motion or Rest. And upon this very account do they explode Qualities, considered as Entities really distinct from these Modes; because in the Generation and Alteration of them, there would be Real Entities made Out of Nothing, or without a Cause; whereupon they Resolve these Qualities into Mechanism and Fancy. Cudworth (1678: 755). It is well known that Descartes viewed the deliverances of colour experience with suspicion; but what is the bearing of this on Locke’s famous distinction between primary qualities, such as shape, size and texture, and secondary qualities, such as colour, taste and sound? Discussions of the intellectual background to Locke’s primary–secondary quality distinction tend to be dominated by Boyle. This is rather surprising. In the first place, Boyle’s ‘corpuscularian theory of matter’ is supposed to be neutral on the points of doctrine that differentiate broadly speaking mechanistic theories of matter, such as Cartesian and atomistic theories: being ‘a person of a reconciling disposition’, Boyle prefers to regard theories which explicate natural phenomena mechanistically by way of minute bodies, or corpuscles, as ‘one philosophy’ (1661: 356). Acknowledging Boyle’s influence on Locke is therefore consistent with recognizing the influence on Locke of corpuscu- larians other than Boyle. Besides, Descartes’s influence on Locke is anyway well documented. During his time as an undergraduate at Oxford, for instance, Locke made detailed notes on the most complete statement of Descartes’s mechanistic science, The Principles of Philosophy (Milton, 1994). The experience was obviously beneficial, as in response to Edward Clarke’s request that Locke suggest reading for his son, Locke – around the period that he is thought to have completed the final extant draft of the Essay Concerning Human Understanding, Draft C – recommended Descartes’s scientific theory as ‘perhaps the most intelligible and most consistent with it British Journal for the History of Philosophy 16(2) 2008: 273 – 291 British Journal for the History of Philosophy ISSN 0960-8788 print/ISSN 1469-3526 online ª 2008 BSHP http://www.informaworld.com DOI: 10.1080/09608780801969092