 Some proposed cases of (i) require the laws of nature to be contingent. Although the laws of nature are widely held to be contingent, some philosophers hold that the laws are necessary, on the basis of essentialist arguments that are much of a piece with Kripke’s essentialist arguments, even if strictly independent of them. The anti-descriptivist arguments regard the observable properties of instances of a kind C as nomic consequences of the essence of C. If the laws of nature are metaphysically necessary then D will be a necessary property of instances of C also. Thus, instances of (i) will not be available. If the laws are necessary, then the melting point of gold will be necessary just as the atomic number of gold is. However, not all observable properties are consequences of the laws alone. Some are consequences of the laws plus contingent environmental factors. Thus the perceived colour of an object may change with environmental differences. Thus if looking yellow is a component of D, then a possible world in which gold does not look yellow (because of unusual atmospheric effects)—surely a genuine possibility—would be a counterinstance of type (i). On the other hand, it might be argued, that the proper component of D would be being yellow, in which case we will have the makings of an epistemological argument against descriptivism (see below).