Meaning seems to shift from context to context; how do we know when someone says "grab a chair" that an ottoman or orange crate will do, but when someone says "let's buy a chair," they won't? Somehow, in spite of this slipperiness, we usually understand each other in conversations, and have straightforward ways of querying each other when we sense a gap in understanding. We seem capable of using ordinary language to communicate with as much precision...