NEWSPAPERS are the Greek chorus of our time - a voice of the people. The public wants to know what is going on in the chambers of power, what today's sages of economics, foreign relations, and social welfare have to say. The purpose of newspapers - to tell the citizen what he needs to know so he can make informed decisions for himself and his society - does not change with time. Newspapers reflect the existential ``now'' of public thought. The best newspapers influence public thought for the better. They inform the public consciousness, balance its perceptions, illumine its recesses. The best newspapers lead. They teach. They do not mire down in excuses for failure. Some newspapers are taking a broader view of publishing. The Monitor has launched magazine, radio, and television journalism enterprises, to expand its presence in public thought. Monitor Cable, a new national cable channel, will start up in May, 1991. But if newspapers themselves fade away, it will be less because of technology than because their voices drift from identifying with the public, their readers.