 Cases of (ii) may be more readily available, since the necessity of laws may rule out a particular kind having different possible sets of manifest properties, but does not rule out two distinct possible kinds having the same manifest properties. Indeed, the case of jadeite and nephrite is often referred to as an example of the latter. Along the same lines, we may imagine that something like fool’s gold, iron pyrites, is just like gold in observable properties, differing only in chemical constitution. We may imagine that there were creatures to all appearances like cats, but which are internally robots; or just like tigers but had reptilian innards. These are all metaphysically possible, so the arguments go; hence, possession of the relevant properties cannot suffice for membership of the corresponding kind.