Progress is tough on teachers. They think they've got their subject down pat and then someone discovers a new batch of facts and the teachers have to relearn the subject if they're going to teach it properly. Teachers have to be students.

So much is being added to what everyone ought to know if they're going to be considered "educated" that it must be difficult for a teacher to keep up. The number of facts that ought to be known by an educated person has multiplied by a thousand over what it was 50, 20 or even 10 years ago.

Whether teachers are conveying information about art, physics, sociology, chemistry or history, so much new has been added that teachers have to be master editors and condensers.

Since I went to school, eight U.S. presidents, two states, three wars, half a dozen major political scandals, Churchill, Hitler, Stalin, Khrushchev, Gorbachev, space exploration, AIDS, atomic energy, 21 Super Bowl winners and the names of 10,000 important statesmen, artists, performers, musicians and writers have been added to what young people ought to learn about if they're going to function intelligently in our society.

If teachers add a detailed study of World War II to the history course, they must cut down on the Civil War. There's room in our brains, but there's only so much time to put information in them.

In a new book called Cultural Literacy, E.D. Hirsch Jr. writes about the importance, for a country, of widely shared information. When everyone understands a lot of the same things without having to be given a long explanation every time they come up, it saves time and promotes more effective nationwide communications.

This is why public education in America is so important. We are all taught the same basic things. We all learn the same language and become mutually familiar with the same history, the same literature and the same general culture.

I often pause when I'm writing something and wonder if I can assume that readers or viewers will understand some reference I make without an explanation. We should all understand more than just the bare words when we're reading something or else a piece of written material gets tediously long with explanations of the obvious.

Some black Americans have complained that the Scholastic Aptitude Test for high school students trying to get into college is biased against blacks because the test asks questions that are outside black culture. Some Spanish- speaking Americans don't want to have to learn English.

There's nothing wrong with black Americans or Spanish-speaking Americans maintaining an independent culture of their own, but if they're to succeed in the world, they're going to also have to be educated to the mainstream American culture as everybody else.

I say all this, even though I'm happy I'm a little dumb.