 A few scholars maintain that heat, e.g., is nothing other than a sensation on the strength of Principles 1.70–71 (Vinci 1998: 199–200; MacKenzie 1990: 114–16). However, the scientific writings offer mechanist accounts of light and color as specific sorts of motions of insensible particles and suggest other SQs, too, are micro physical configurations (e.g., Optics, CSM 1.153, 155–6; AT 8.84–5, 88). Cottingham (1990: 237–38) among others cites a text that may seem to identify sensible qualities with causal dispositions (CSM 1.285; AT  8.323),[3]  but Wolf-Devine (1993: 46–8) convincingly argues that the passage refers to mechanist microstructures. Other commentators maintain that Descartes either vacillates between mental and physical views of color or has an inconsistent theory (M. Wilson 1992: 228, 234; Wolf-Devine 1993: 46–8). However several more charitable interpretations accommodate both. According to Atherton (2004), Descartes’ opposition to certain scholastic doctrines motivates a bifurcated theory of color consisting of a mechanist physiological account paired with a mentalist psychological account of sense perception. She finds nothing that unites the parts of an essentially dualist theory of perception. According to Nolan (2011a), Descartes is a nominalist about SQs: they are abstractions from experience that have no de re counterparts. They are names we use to refer to both certain ideas and certain bodily modes. However, it seems the status of SQs should be understood as that of entities that emerge in the mind-body union in an environment such as ours (see Alanen 2005: 147–164; also Brown &amp; Normore [2019: 185–6] who argue that the union is a subject of predicates without mentioning SQs). This view of SQs is explicit in Principles, Part I (CSM 1.208–09; AT 8.22–23).