 Thus far Kripke’s account of the semantics of natural kind terms treats them very much on a par with proper names, suggesting that kinds are much like abstract individuals, being potential recipients of singular reference—Millianism has been extended from proper names of individuals to natural kind terms. (Mill’s own view of ‘general terms’ was not Millian in this sense, but closer to a Fregean view.) Putnam gives a more elaborate account of the reference of natural kind terms, which apparently does not depend on treating kinds as abstract individuals. According to Putnam, the extension of a natural kind term is fixed by ostending or otherwise identifying a sample of the kind and appealing, explicitly or implicitly, to a ‘same kind relation’. Thus the extension of ‘water’ includes all and only those things that bear the same kind relation to some sample, which may be specified loosely, for instance as ‘the watery stuff around here’ (where ‘watery’ is defined in terms of the manifest characteristics of water, not in terms of ‘water’). (Note that Putnam says ‘same liquid relation’, but that would not provide the extension of a natural kind term, since it would exclude the gaseous and solid phases of water.) Putnam (1975a) thereby extends the notion of rigid designation to general terms, since (a) the same kind relation is a cross-world relation, and (b) it is anchored to a specific, actual world sample. Consequently all samples of water in all possible worlds will bear the same kind relation to one another. That this excludes XYZ depends upon its being the case that a sample that does not share the ‘important physical properties’ of our sample cannot be of the same kind.