“A third problem is called “co-reference.” Say you start talking about an individual by referring to him as the tall blond man with one black shoe. The second time you refer to him in the conversation you are likely to call him the man; the third time, just him. But the three expressions do not refer to three people or even to three ways of thinking about a single person; the second and third are just ways of saving breath. Something in the brain must treat them as the same thing; English isn’t doing it.”