In a manner of speaking

September 23, 2007|George Scialabra

For a long time, the main argument against the theory of evolution was the human soul, and the chief evidence for the existence of the soul was language. All humans and only humans have language; therefore humans must have a unique essence, which philosophers and theologians called "soul." "Explain that!" they cried defiantly at scientists. And the scientists couldn't.

On other grounds, however - including geology, which showed that the earth was old enough for very large changes to have occurred very gradually; archeology, which has discovered many of the innumerable links in the skeletal development of humans and other animals; and genetics, which has banished the concept of "essence" from biology - the debate over evolution is now settled. Still, what about language? We know now that language must have an evolutionary explanation, because that is the only kind of explanation there is for any human trait. But what might that explanation be?

Naturally, the answer depends on what language itself is. Until the mid-20th century, the usual answer was that language was just another skill, like chess or tennis. Children learned to speak by being taught, just as they learned games or sports. This behavioral approach seemed obvious until Noam Chomsky pointed out that this is not how children learn to speak at all. Placed among speakers, they automatically begin speaking, just as plants, placed in moist soil, automatically begin growing. Placed among chess players, however, children do not automatically begin playing chess. It looks as though language ability is innate, like visual ability - an organ rather than a skill.