What was going on when I was born?

The best- known Republican proposal for a so- called flat tax would cut taxes for upper-income taxpayers by about 15 percent while raising taxes 2 to 3 percent for middle-income taxpayers, according to a preliminary analysis by the Joint Committee on Taxation released today. The proposal is the Fair and Simple Tax, or FAST, plan backed by Representative Jack Kemp, Republican of New York, and Senator Robert W. Kasten Jr., Republican of Wisconsin. The analysis by the nonpartisan Joint Committee also found that the best-known Democratic proposal for tax simplification would not change the current distribution of the tax burden among income clases. This proposal, the Fair Tax Plan, is co-sponsored by Senator Bill Bradley of New Jersey and Representative Richard A. Gephardt of Missouri.

Legislation that would open Japan's huge telephone market to competition will probably not be passed by Japan's Parliament in the current session, which ends today. The legislation, anxiously awaited by American telecommunications companies as well as Japanese, would turn the state-owned Nippon Telegraph and Telephone Public Corporation into a private company starting next April 1 and end its monopoly over telephone service. While there is still a remote chance that a compromise on the package will be reached today, Japanese newspapers this morning were reporting that the ruling Liberal Democratic Party had essentially given up and decided to hold the package of three telecommunications bills over until the next session. The important question now is how soon the next session of Parliament will be held. The bills are expected eventually to pass, but how soon they pass will determine whether the N.T.T. reorganization will have to be postponed beyond April 1.

Governor Cuomo said today that he had ordered state officials to review charges of child abuse at a Bronx day-care center to determine if the situation was isolated or part of a widespread problem. The Governor announced the first state involvement in the day-care case as the City Comptroller, Harrison J. Goldin, proposed that all child-care services be taken away from New York City's Human Resources Administration and put into a new agency reporting directly to the Mayor. ''We've had a lack of accountability,'' Mr. Goldin said. In a news conference at City Hall, Mayor Koch was noncommittal on the proposal, but said Mr. Goldin's idea would be examined.

The Administration sent Navy minesweeping helicopters and about 200 servicemen on their way to the Middle East today to help Egypt rid the Gulf of Suez area of explosives that have damaged commercial shipping. The military force began leaving the Norfolk, Va., Naval Air Station at midnight Monday aboard C-5 jet transports, according to the Department of Defense. Pentagon sources said the airlift, which will take two days to complete, was destined for Rota, Spain, site of a large United States base near Gibraltar. From there, they said, the helicopters will be loaded onto a Navy ship for transport across the Mediterranean into the Red Sea, where joint minesweeping operations with the Egyptians are to begin within 10 days.

To the surprise of some of his own supporters, President Reagan's re-election campaign has been thrown on the defensive and caught up in uncertain statements and apparent contradictions over the issue of raising taxes to reduce the Federal deficit. Two weeks ago the President's top aides seemed delighted by the unusual statement of Walter F. Mondale that he would raise taxes if elected President. A senior White House official predicted then that Mr. Reagan would easily dismiss the Democratic Presidential nominee's parallel contention that the President would also raise taxes in 1985. Indeed, the day after Mr. Mondale made his assertion, in his acceptance speech in San Francisco, a senior White House aide assured a reporter that the Reagan campaign had just been handed a wonderful gift: an undreamed-of opportunity to hammer at one of Mr. Reagan's favorite messages. Impression Seen Unchanged White House officials maintained today that their basic point was still getting across. ''We still think the impression is out there that Ronald Reagan doesn't want to raise taxes, and Walter Mondale does want to raise taxes,'' said one Presidential aide.

Bradley Pierce owned and managed New York nightclubs for 15 years, staying up all night and living what he remembers as ''a pagan life.'' But gradually he came to feel something was missing. Ten years ago, he left New York for a Trappist monastery, where he got up every day at 3 A.M. to pray. Last year, at the age of 47, he was ordained a Roman Catholic priest at Holy Apostles Seminary in Cromwell, Conn. Father Pierce is among what Protestant and Catholic seminary officials say is a significant and rising number of people choosing the ministry as a second career. They are men and women who turn to religious life in middle age, often after fast-paced, successful careers in business or the professions.

Wall Street brokers may be cheering the record stock volume of recent days, but the sudden rally will hardly cure all the security industry's ills. Personnel layoffs and expense cuts are the order of the day at dozens of investment houses. Most publicly owned firms lost money in the second quarter. And yesterday, just three months after Lehman Brothers Kuhh Loeb was sold to Shearson American Express, Becker Paribas announced its sale to Merrill Lynch. Indeed, the Securities Industry Association estimates that the first six months of this year were the worst for brokers in more than six years. With all this turmoil, many experts believe Wall Street may be headed for another wave of consolidations, similar to those that shrank the industry in 1970 and again seven years later.

IN the last six months, Linwood McManus has finally begun to realize a pipe dream that he shares with countless others. Since February, he has been the proud if somewhat harried owner of the Cafe Calypso in Boston's historic South End. He is also the wine buyer, personnel manager, occasional headwaiter and full-time chief cook. True, he has a bottle washer, as well as a few other kitchen and dining-room helpers, but most of the burdens of the 55-seat restaurant fall on Mr. McManus's own shoulders. He wouldn't have it any other way.

Walter F. Mondale is backing away from a vow he made in the primary campaign to dismiss President Reagan's appointees to the United States Commission on Civil Rights. Aides to Mr. Mondale clarified his intentions today. On Monday night the commission's chairman, Clarence M. Pendleton Jr., sharply criticized Mr. Mondale's positions on civil rights, saying they were ''worse'' than Mr. Reagan's. Mr. Pendleton, a Republican, was appointed by Mr. Reagan. In a portion of his standard campaign speech, repeated in the debates with rival Democratic candidates for Presidential nomination, Mr. Mondale often accused the Administration of having ''trashed'' the Civil Rights Commission.

For the aluminum industry, a potent recovery has been checked this summer by an unexpected tumble in prices. The industry regained its feet in 1983 after its worst recession - several years of decreasing consumption and heavy losses - and began 1984 with high hopes. Wall Street analysts hung out the buy sign on the major aluminum company stocks and predicted heady results in a recovering economy. Indeed, the major companies reported strong first-half gains.

Uganda reportedly suspended a United States military aid program today and barred an American colonel from visiting the country in response to criticism by the Reagan Administration about human rights abuses. Administration officials, repeating charges first made over the weekend, said today that the Ugandan Army had killed thousands of civilians in the last year in an effort to combat rebels. The officials said estimates by some private relief agencies placed the number of deaths at more than 100,000. ''It's as bad a situation as we've seen anywhere in the world in recent years,'' a senior State Department official said.

''I am pleased to report that the higher revenue base indicated in the revised projections strengthens our hope for a future tax cut.'' - Governor Cuomo. (A1:6.)