Stephen Schiffer

There are two things we must know in order to know what vagueness is. We must know what kinds of things can be vague. Evidently, predicate and sentence types can be vague, but what about tokens of those types? What about statements and other speech acts? What about abstract entities such as properties and propositions? And what about names and the boundaries of physical objects? Then, of course, for each kind of thing that can be vague, we must know in what vagueness for that kind consists. Needless to say, that there are these two questions doesn’t mean that we should try to answer the first before trying to answer the second.

Suppose we think in a language of thought. Then Paul Boghossian' is prepared to argue, first, that there may be ambiguous Mentalese expression types that have unambiguous tokens, and, second, that the way in which this is possible allows for otherwise valid theoretical or practical reasoning to be rendered invalid owing to equivocation of a sort that may be undetectable to the reasoner. Paul sees this as a possible basis from which to launch an argument for what some might call "narrow content", and this is a question I'll take up later

In The Things We Mean I argue that there exist such things as the things we mean and believe, and that they are what I call pleonastic propositions. The first two chapters offer an initial motivation and articulation of the theory of pleonastic propositions, and of pleonastic entities generally. The remaining six chapters bring that theory to bear on issues in the theory of content: the existence and nature of meanings; knowledge of meaning; the meaning relation and compositional semantics; the relation between content-involving facts and underlying physical facts; vagueness and indeterminacy; conditionals; normative discourse; and the role of propositional content in explanation, prediction, and knowledge acquisition.