In ‘A New Route to the Necessity of Origin’, Rohbraugh and deRosset offer an argument for the Necessity of Origin appealing neither to Suffciency of Origin nor to a branching-times model of necessity. What is doing the crucial work in their argument is instead the thesis they name ‘Locality of Prevention’. In this response, we object that their argument is question-begging by showing, first, that the locality of prevention thesis is not strong enough to satisfactorily derive from it the intended (...) conclusion, and, second, that the argument is not sound unless the Necessity of Origin is operating as an implicit premiss. (shrink)

A thorough critique (extracted from the author’s 1979 doctoral dissertation) of Kripke’s purported derivation, in footnote 56 of his philosophical masterpiece /Naming and Necessity/, of nontrivial modal essentialism from the theory of rigid designation.

Possible worlds present a formidable challenge for the lover of desert landscapes. One cannot ignore their usefulness; they provide, as David Lewis puts it, “a philosophers’ paradise”.1 But to enter paradise possibilia must be fit into a believable ontology. Some follow Lewis and accept worlds at face value, but most prefer some other choice from the current menu. Part of Chihara’s book is a critical discussion of some of these menu options: Lewis’s modal realism, Alvin Plantinga’s abstract modal realism, Graeme (...) Forbes’s anti-realism and Gideon Rosen’s modal fictionalism. These discussions are very detailed and conversant with the literature. The discussions of Forbes and of paradox within Plantinga’s system are particularly enlightening. The rest of the book is devoted to Chihara’s positive project: developing an account of the status of model theory for non-modal logic, and then applying it to the modal case. The prize is an understanding of possible worlds semantics that requires no commitment to possible worlds at all What does the relativized notion of truth in an interpretation studied in model theory have to do with plain old truth? Chihara’s answer involves “connecting theorems” that relate truth-in to truth. A “natural-language proto-interpretation of the sentential calculus” is a function that assigns meanings of declarative sentences of English to sentence letters. Where I is an NLPI of SC and φ is a sentence letter, Chihara uses ‘[φ/I ]’ to refer to “φ with the meaning it has been assigned by I ” ; where φ is not atomic, he says. (shrink)

Saul Kripke has claimed that there are necessary connections between material things and their material origins. The usual defences of such necessity of origin theses appeal to either a sufficiency of origin principle or a branching-times model of necessity. In this paper we offer a different defence. Our argument proceeds from more modest ‘independence principles’, which govern the processes by which material objects are produced. Independence principles are motivated, in turn, by appeal to a plausible metaphysical principle governing such processes, (...) their invulnerability to non-local prevention. We outline the new argument, and distinguish it from both of the usual defences. (shrink)

In this paper, I examine the case that has been made for origin essentialism and find it wanting. I focus on the arguments of Nathan Salmon and Graeme Forbes. Like most origin essentialists, Salmon and Forbes have been concerned to respect the intuition that slight variation in the origin of an artifact or organism is possible. But, I argue, both of their arguments fail to respect this intuition. Salmon's argument depends on a sufficiency principle for cross-world identity, which should be (...) rejected, if - as Salmon concedes - a given artifact might have been originally made from slightly different material. Similarly, Forbes's argument succeeds only if essentially the same argument can be used to establish a claim that - by his own admission - is too strong, namely that no variation, however slight, in an organism's origin is possible. (shrink)

A New Route to the Necessity of Origin’, Guy Rohrbaugh and Louis deRossett argue for the Necessity of Origin in a way that they believe avoids use of any kind of transworld constitutional sufficiency principle. In this discussion, we respond that either their arguments do imply a sufficiency principle, or else they entirely fail to establish the Necessity of Origin.

ln "Possibilities and the Arguments for Origin Essentialism" Teresa Robertson (1998) contends that the best-known arguments in favour of origin essentialism can succeed only at the cost of violating modal common sense—by denying that any variation in constitution or process of assembly is possible. Focusing on the (Kripke-style) arguments of Nathan Salmon and Graeme Forbes, Robertson shows that both founder in the face of sophisticated Ship of Theseus style considerations. While Robertson is right that neither of the arguments is compelling (...) as formulated, each can be modified to fend off her particular counterexamples; these modifications do not differ in kind from those already needed to deal with ordinary Theseus cases, requiring only a further narrowing of the sufficiency clause from which the necessity of origins is derived. (shrink)