Explicit and Implicit Information

Alfred Charles William Harmsworth, 1st Viscount Northcliffe (1865–1922), was the owner of two British newspapers, the Daily Mail and the Daily Mirror. He is credited with first pointing out that “Dog Bites Man” is an unlikely headline, whereas “Man Bites Dog” might herald a newsworthy story. Modern journalists are referring to the same phenomenon when they point out that no one ever writes a story about a plane because it did not crash. The point is obvious to journalists and to ordinary citizens seeking to avoid newsworthy flights. But it is missed by the adherents of Noam Chomsky's linguistic theories and by practitioners of a branch of linguistic engineering that has come to be known as natural language processing (NLP). This is curious because, but for an interest in language, these two groups have little in common.

Chomsky argues against the behaviorist view of language acquisition espoused, for example, by Skinner, on the grounds that even very large quantities of raw linguistic data contain neither the kind nor the quantity of information that would enable a general learning device to acquire everything that it would have to know to use the system as humans do.