Peter Pagin

The standard argument against ordered tuples as propositions is that it is arbitrary what truth-conditions they should have. In this paper we generalize that argument. Firstly, we require that propositions have truth-conditions intrinsically. Secondly, we require strongly equivalent truth-conditions to be identical. Thirdly, we provide a formal framework, taken from Graph Theory, to characterize structure and structured objects in general. The argument in a nutshell is this: structured objects are too fine-grained to be identical to truth-conditions. Without identity, there is no privileged mapping from structured objects to truth-conditions, and hence structured objects do not have truth-conditions intrinsically. Therefore, propositions are not structured objects.

När är det befogat att tillskriva mening (betydelse) till beteenden? I början av 2001 presenterade en av Stockholms gratistidningar en artikel om det så kallade kroppsspråket. Rubriken var "Kroppen ljuger inte". Ämnet för artikeln var egentligen den evidens som en persons gester och kroppshållning ger om hennes sinnestillstånd eller personlighet ("självsäker", "stressad", "osäker", "nervös", "ljuger", "arg", "manipulativ", "spänd" eller "misstänksam"). Enligt artikeln är dessa gester och kroppshållningar inte avsedda att ge andra information om ens inre tillstånd. De är alltså inte kommunikativa. Likafullt ger de sådan information, ibland kanske mot personens egen önskan. Trots det beskrivs de som semantiskt meningsfulla: "Varje min och rörelse kan tolkas symboliskt".

The paper discusses the question whether T-theories explain how it is possible to understand new sentences, or learn an infinite language, as Davidson claimed. I argue against some commentators that for explanatory power we need not require that T-theories are implicitly known or mirror cognitive structures. I note contra Davidson that the recursive nature of T-theories is not sufficient for explanatory power, since humans can work out only what is computationally tractable, and recursiveness by itself allows for intractable computational complexity. I finally consider the complexity of T-theories, transformed into term rewriting systems, and find that the complexity of such systems is indeed tractable. Therefore Davidson's claim stands, even though a further condition had to be met.

Natural kind terms have exercised philosophical fancy ever since Kripke, in Naming and Necessity, claimed them to be rigid designators. He there drew attention to the peculiar, name-like behavior of a family of prima facie loosely related general terms of ordinary English: terms such as ‘water’, ‘tiger’, ‘heat’, and ‘red’. Just as for ordinary proper names, Kripke argued that such terms cannot be synonymous with any of the definite descriptions ordinary speakers associate with them. Rather, the name-like behavior of these so-called natural kind terms is to be explained, just as in in the case of proper names, by the doctrine of rigid designation. And as a consequence of thus extending the notion of rigid designation to general terms, he famously endorsed the claim that so-called ‘theoretical identifications’, i.e. statements like (1) Water is H2O, are necessary, if true