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Metaphysical ~ necessity has been presented by Saul Kripke and by Hilary Putnam as being both broad in scope and metaphysical -perhaps more accurately, ontological -in character. Discussing the claim that water is H20, Putnam has claimed this:
Once we have discovered that water (in the actual world) is H 20 nothing counts as a possible world in which water isn't H20. In particulax, if a 'logically possible' statement is one that holds in some 'logically possible world', it isn't logically possible that water isn't H 20.1 That is, he has claimed that if water is H20, it is logically necessarily so, it is true in all possible worlds. In this matter of scope, Kripke agrees. Discussing a similar case he writes that ...such statements ...are not contingent truths but necessary truths in the strictest possible sense? Further, for Kripke, ...a good deal of what contemporary philosophy regards as mere natural necessity is actually necessity tout court. 3 It is this shared view of Kripke and Putnam that I wish to discuss, putting aside the second claim as to the metaphysical -or ontological -character of the necessity of such claims as 'Water is H 2 0 ' . In the two sections which follow I shall argue that Kdpke and Putnam are wrong in their shared view of the scope of metaphysical necessities; I shall argue that there is a possible world in which -to introduce the example I shall use for the rest of my arguments -gold fails to have atomic number 79, despite the agreement on the part of Kripke and Putnam, that it is, if true, metaphysically necessarily true that gold have atomic number 79.
It is crucial to an acceptance of the metaphysical necessity of such claims Philosophical Studies 39 (