 The contrast provides the foundation of Reid’s distinction between qualities listed as primary and secondary. The senses give us “a direct and a distinct” notion of the primary qualities and inform us “what they are in themselves”, but “only a relative and obscure” notion of the SQs, one that tells us “only that they … produce in us a certain sensation” and “leave us in the dark” about “what they are in themselves” (Reid 1785 [2002: 200–203]; 1764 [1997: 61–2]). By a “distinct notion”, Reid means one that provides clear and distinct understanding of its object. Our notion of hardness is said to inform us perfectly of what that quality is; “it is manifest to sense” (Reid 1785 [2002: 203]). By a “direct notion”, he means one that is not relative. A relative notion of a thing, “is, strictly speaking, no notion of the thing at all, but only of some relation which it bears to something else” (Reid 1785 [2002: 200–03]). For instance,