Alan Sidelle

ABSTRACT: Rudolf Carnap’s “Empiricism, Semantics and Ontology” (ESO) has received a good deal of sympathetic interest over the years from philosophers who are not particularly sympathetic to verificationism, or suspicious of metaphysics in general. Recent work has favorably cited ESO in connection with doubts about the genuine content of debates in the metaphysics of material objects. But, when we look at how Carnap introduces his central notion of a ‘framework’, and the questions he wants to use it to deflate, there seem to be significant differences in his approach and aim from that of contemporary deflationists about the metaphysics of material objects. This paper first looks at some of these differences, and suggests a way of seeing them as arising more from differences in focus and interest than fundamental approach. However, a further question is whether philosophers who may entirely disagree with Carnap about abstract entities, or the substantiveness of the debate between Realists and Idealists – possibly all of his negative conclusions in ESO - can really be seen as heirs to his approach and argument therein. We look first at his discussion of the Realism/Idealism debate, to sort out different aspects of his analysis, and determine to what extent one can disagree with it while not thinking this undermines other analyses using the same general strategy. In the course of this, we are able to distinguish the basic Carnapian analysis of metaphysical disputes, from the question of whether, if the analysis is correct, this actually subverts the disputes. I suggest that, if we put verificationism aside, ESO really provides us with an approach and a type of skeptical challenge more than an argument, and it is open to contemporary philosophers to think that this skeptical challenge can (or can’t) be met, or can be supplemented by further argument, on a case by case basis.

The phenomenon of rigid designation - in particular, de jure rigidity - is typically treated metaphysically. The picture is: reference is gained in a way that puts no constraints on what an object in other worlds, or counterfactual situations must be like, in order to be the referent of that term, other than 'being this thing'. This allows 'pure metaphysical' investigation into, and discovery of 'the nature' of the referent. It is argued that this presupposes a 'privileged' ontology, of a sort that is far from obvious. An alternative picture of rigidity is sketched, terms have associated criteria of identity and criteria of application for counterfactual situations. A term is rigid when these coincide. Aside from being a better account of rigidity, it also undermines the picture of rigid terms allowing us to 'metaphysically' investigate the nature of the referent: matters of identity and essence for the referent are settled by these semantic constraints (though it can be done in a way that allows are a posteriori necessities).

Many philosophers believe that identity through time cannot depend on features extrinsic to the relata and relations between them. This goes with the view that one must deny identity in cases for which there is a `duplication case'-a case just like the first, but for an additional, `external' element which provides an equal or better `candidate' for identity with one of the relata. Such friends of intrinsicness cannot remedy the failure of continuity of function/form to be one-one by non-branching or closest competitor clauses. The obvious intrinsic approach-perhaps taken for granted-appeals to considerations of quantity of matter, requiring over 50% shared matter between identicals. But this rules out plausible cases of halving and doubling for which there are not duplication cases. After bringing out this problem, I ask what makes duplication cases possible, and use this to formulate an intrinsic condition which allows identity whenever there is continuity of function, but no threat to intrinsicness via duplication cases.

Plausible recent arguments for the existence of necessary truths a posteriori have led many philosophers to believe, at least implicitly, that conventionalism about necessity is false, and that necessity is in fact a real-world quantity. Necessary truths, on this view, are no more independent upon our linguistic conventions than any other truths; assertions of necessity and essential predications are, like any other claims, true or false as they correspond or not to a wholly independent reality. I believe that this view is not supported by the finding of necessary truths a posteriori, and further, that we have excellent reason to reject this realism about necessity, and to accept instead a conventionalist account. My dissertation attempts to argue for this view, and to present and defend such a conventionalist account. ;In Chapter One, I present a conventionalist explanation of necessary truths a posteriori, and thus argue that the existence of such truths does not establish realism about necessity. My account makes use of general conventions which I call 'general principles of individuation.' If these principles are products of our conventions, then we can both allow for and explain how there can be such 'empirical' necessary truths within a conventionalist framework. ;Chapter Two argues that conventionalism about necessity and essences has traditionally been grounded in metaphysical worries about necessity, not upon now outdated epistemological and semantic views, as is often claimed by the opponents of conventionalism. ;In Chapter Three, I present my central arguments for conventionalism and against realism about necessity. I argue that only conventionalism can explain how we have the knowledge that we do of what is necessary, and further, that it is not even clear that we can make sense of necessity as an independent feature of the world. Chapter Four responds to worries stemming from the fact that my account requires that there be systematically important analytic truths. ;Finally, in Chapter Five, I attempt to apply my findings to the theory of reference. I argue that if conventionalism about necessity and essences is true, then empiricist semantics must be basically correct, and that causal theories of reference must thus be either compatible with empiricist semantics, or false