Manley and Wasserman's PROP account of dispositions has been influential in the recent debate about the nature of dispositions. In this paper, I will bring under scrutiny one crucial step in Manley and Wasserman's reasoning leading to the PROP account. The step is one where they abandon what they call ‘MOST’, the idea that x is disposed to M when C iff x would M in most cases where C obtains. I will argue below, however, that this step is invalid.

This thesis proposes that key, competing theories of dispositions mistake and conflate how we identify, designate and talk about dispositions and dispositional terms for the nature of dispositions and the meaning of dispositional terms when they argue that: a) dispositions are extrinsic properties of their bearers (Boyle 1666) b) all properties are purely dispositional (Bird 2007) c) all properties are purely categorical (there are no dispositional properties) (Armstrong in AMP 1996) d) dispositional and categorical properties are separate and distinct properties (...) (Prior, Pargetter and Jackson 1982). In so doing these theories make unwarranted and unsupported ontological conclusions about dispositions. The thesis traces the principal source of this confusion and conflation to a reliance on the counterfactual analysis of dispositions that wrongly encourages the conflation of a disposition (say fragility) with its manifestation (shattering). There is good reason to hold that the counterfactual analysis of dispositions is false — the truth of a counterfactual statement (such as “if x were dropped x would break”) is neither necessary nor sufficient for the truth of a dispositional ascription (such as “x is fragile”). (shrink)

This dissertation argues for Semantic Variance, the thesis that nearly every utterance is such that there is no proposition that more than one languge user takes to be that utterance's truth-conditional content. I argue that Semantic Variance is problematic for standard theories concerning the nature of communication, the epistemic significance of ordinary disputes, the semantics of speech reports, and the nature of linguistic competence. In response to the problems arising from the truth of Semantic Variance, I develop new accounts of (...) the transmission of relevant information, ordinary disputes, and the semantics of speech reports. Towards the end of the dissertation I outline a pluralistic account about the nature of communication and linguistic competence. (shrink)