Plato’s Problem

Plato’s Problem was expressed generally by Bertrand Russell: “How comes it that human beings, whose contacts with the world are brief and personal and limited, are nevertheless able to know as much as they do know?” The problem arises in the domain of language acquisition in that children attain infinitely more than they experience. Literally so, we shall see: they attain a productive system, a grammar, on the basis of very little experience. So there is more, much more, to language acquisition than mimicking what we hear in childhood, and there is more to it than the simple transmission of a set of words and sentences from one generation of speakers to the next. There is more to it than a reproduction of experience and, in maturity, our capacity goes well beyond what we have experienced.

Consider some subtleties that people are not consciously aware of. The verb is may be used in its full form or its reduced form: people say Kim is happy or Kim’s happy. However, certain instances of is never reduce, for example, the underlined items in Kim is happier than Tim is or I wonder what the problem is in Washington. Most people are not aware of this, but we all know subconsciously not to use the reduced form here. How did we come to this? The question arises because the eventual knowledge is richer than relevant experience. As children, we heard instances of the full form and the reduced form, but we were not instructed to avoid the reduced form in certain places; we had no access to “negative data,” information about what does not occur.