The relation between two systems of attitude ascription that capture all the empirically significant aspects of an agents thought and speech may be analogous to that between two systems of magnitude ascription that are equivalent relative to a transformation of scale. If so, just as an objects weighing eight pounds doesnt relate that object to the number eight (for a different but equally good scale would use a different number), similarly an agents believing that P need not relate her to (...) P (for a different but equally adequate interpretive scheme could use a different proposition). In either case the only reality picked out by any system of ascription is what is common to all equivalent rivals. By emphasizing some contrasts between decision theory and belief-desire psychology, it is argued that if attitude ascription is appropriately analogous to measurement then not only is being related to a proposition an artifact of the system of representation chosen, so are belief and desire. (shrink)

In his account of probable reasoning, Poincaré used the concept, or at least the language, of conventions. In particular, he claimed that the prior probabilities essential for inverse probable reasoning are determined conventionally. This paper investigates, in the light of Poincaré's well known claim about the conventionality of metric geometry, what this could mean, and how it is related to other views about the determination of prior probabilities. Particular attention is paid to the similarities and differences between Poincaré's conventionalism as (...) it applies to probabilities and de Finetti's subjectivism. The aim of the paper is to suggest that in accounts of the development of ideas about probable reasoning, particularly those customarily described as Bayesian, Poincaré's discussion deserves more attention than it has so far received. (shrink)