Propositional attitude

In logic, the formal properties of verbs like assert, believe, command, consider, deny, doubt, imagine, judge, know, want, wish, and a host of others that involve attitudes or intentions toward propositions are notorious for their recalcitrance to analysis. (Quine 1956). Indiscernibility of identicals One of the fundamental principles governing identity is that of substitutivity, also known as fungibility — or, as it might well be called, that of indiscernibility of identicals. It provides that, given a true statement of identity, one of its two terms may be substituted for the other in any true statement and the result will be true. It is easy to find cases contrary to this principle. For example, the statements: :(1) Giorgione = Barbarelli, :(2) Giorgione was so called because of his size. are true; however, replacement of the name Giorgione by the name Barbarelli turns (2) into the falsehood: :(3) Barbarelli was so called because of his size. Quine's example here refers to Giorgio Barbarelli's sobriquet "Giorgione", an Italian name roughly glossed as "Big George." The basis of the paradox here is that while the two names signify the same individual (the meaning of the first statement), the names are not themselves identical; the second statement refers to an attribute (origin) that they do not share. ==Overview==

Bertrand Russell introduced the idea of handling propositions like this: How one feels about or regards a proposition is different than what a proposition is – they can be accepted, asserted, believed, commanded, contested, declared, denied, doubted, enjoined, exclaimed, or expected, for example. Different attitudes toward propositions are called propositional attitudes; they are also discussed under the headings of intentionality and linguistic modality. Many problematic situations in real life arise from the circumstance that many different propositions in many different modalities are in the air at once. In order to compare propositions of different colours and flavours, as it were, there is no basis for comparison but to examine the underlying propositions themselves, returning to matters of language and logic. Despite the name, propositional attitudes are not regarded as psychological attitudes proper, since the formal disciplines of linguistics and logic are concerned with nothing more concrete than what can be said in general about their formal properties and their patterns of interaction. ==See also==