What was going on when I was born?

Music and dance have always been allies but, over the centuries, they have been allied in many different ways. One of the most unusual alliances is that of John Cage, the composer, and Merce Cunningham, the choreographer, who this season are celebrating their 40th year of collaboration. The kinds of collaboration they favor are exemplified by the works in the repertory of the Merce Cunningham Dance Company, which opens Tuesday night at the City Center. And, recently, Mr. Cage was happy to talk about the philosophy that brought those works about. Mr. Cage, who turned 70 last year, is one of the most influential composers of our time, noted - among many other things - for his way of altering piano sonorities by placing objects on or between the strings (the ''prepared piano'' is what he calls this use of the instrument) and for his incorporation of chance elements into the process of composition. Together with Mr. Cunningham, he has fashioned a kind of dance in which choreography and music coexist without either art being subservient to the other.

Perhaps it's best not to probe. There are those among us, myself included, who are unable to resist plowing through every kind of theatrical memoir, from full-scale biography to as-told-to pasteup jobs, looking for a little clue that will help explain how an actor or a director arrived at a particular detail we very much liked. These books, as you know, come out 10 to a week, and they are positively crammed with mentions of kindly friends, with the guest lists of dinner parties, even with contractual terms and gloating accounts of how much overtime the male star collected because his leading lady was always late. But if it's an analysis of how a characterization was arrived at, of what inspired a performer to make this gesture rather than that one, of what Ralph Richardson means by flexing his knuckles so much - forget it. Nary a secret will you learn, not a word will carry you deeper into the heart of the creative matter. Performers and directors will tell you about their wives and about their wisdom teeth before disclosing the process that went into the reading of a memorable line, the invention of a memorable bit of business.

Secretary of Defense Caspar W. Weinberger has proposed a new arrangement with Israel to share intelligence findings from the war in Lebanon, according to Reagan Administration officials. Last month Mr. Weinberger rejected a proposal by Israel to share the information. The new proposal has put the Israeli Government in a difficult situation, according to diplomatic officials. On the one hand, they said, Israeli officials think the proposal favors the United States without meeting Israeli needs. On the other hand, they said, Israeli officials want an agreement to help reverse what they see as a downward trend in United States-Israeli relations.

COMMUTERS in the county who have long coped with rail service of varying conditions learned quickly last week, not without discomfort, to cope with similarly varied bus and highway conditions. By midweek, many of the 85,000 rail riders had established new patterns. While special shuttles to Bronx subway stations and buses that normally link Westchester and Manhattan reported increased ridership, some bus drivers, many of them policemen and firemen, said automobiles seemed to be carrying three or four passengers instead of the usual one or two. Commuters who on Monday started their bus journeys at dawn, and their returns at mid-afternoon, were waiting an extra hour or so by Wednesday, confident that they knew the new patterns of bus travel. They remained unhappy, however, about the $5 to $10 daily cost - for bus, subway or parking fees - coming just after having purchased rail commutation tickets. The Metropolitan Transportation Authority said that ticket refunds would be provided for the commuting days lost.

MULLICA TOWNSHIP PICTURE postcards from Puerto Rico brighten the walls of the trailer behind the Elwood primary-middle school here in the heart of the Pine Barrens. The cards and a constant stream of men and women coming to the trailer are evidence that more and more migrant farm workers in New Jersey are choosing to have their children go to school, even if it means forgoing the money they could get by having them work in the fields. Although New Jersey, like other states, has long had a law requiring children to attend school (in New Jersey, attendance is compulsory from age 5 to 16), migrant-farm children often fell between the cracks because they came and went without formal registration. Federal funds to keep track of migrant youngsters began to flow to local districts starting in the late 1960's, following passage of a Federal law that led to the establishment of social and educational services for migrant families.

PASSENGERS on commuter railroads in the metropolitan area will see s ome new sights around their stations within the next three or four y ears - luxury hotels, apartment buildings, office blocks, retail c enters and modern transportation hubs for buses, taxis and l imousines as well as trains. Once considered blighted areas - literally and figuratively ''on the wrong side of the tracks'' - the stations and the land around them now are being rediscovered by builders and are the focus of intensive redevelopment. After years of decline, station areas are being revitalized in Stamford, New Haven and New Rochelle on the New Haven Line of Metro-North; in New Brunswick, Summit, Princeton Junction, Trenton and Newark on the NJ Transit lines and in White Plains on the Harlem Line of Metro-North. On Long Island, the stations and the buildings around them are newer and most of the land is already occupied. But even there, a major hotel opened last month near the Garden City station.

The St. John's basketball players ''walked with kings'' in Madison Square Garden yesterday, according to their coach, Lou Carnesecca, because they won the Big East conference championship by beating Boston College, 85-77, and gained a record 27th victory this season. Chris Mullin, the sophomore who has led the team in scoring for the last two seasons, had 23 points and was voted the tournament's outstanding player. Billy Goodwin, who sparked the first-half play against Boston College just as he did in the spectacular second-half comeback of the semifinal victory over Villanova Friday, had 20 points. And David Russell, who scored on a few driving layups when the Redmen broke the Eagles' press, had 19.

Today, at a time when the average movie costs $11 million to make, another $6 million to market, and when it must sell $35 million worth of tickets to be profitable, studios are searching for additional sources of revenue by distributing movies they previously would have spurned. Thus, Columbia is the proud distributor of ''Parsifal,'' a four-and-a-half-hour movie version of the Richard Wagner opera, directed by the controversial West German Hans-Jurgen Syberberg. Twentieth Century-Fox is delighted that its ''Eating Raoul,'' a black comedy about cannibalism, has earned $2.5 million at 132 theaters. And United Artists spent only $400 to create the advertising materials for ''Lianna,'' a film about a wife who falls in love with a woman, which broke 11 house records in its first nine days at the Embassy 72d Street theater on Manhattan's Upper West Side. ''For 50 years, no major studio ever intentionally made a picture for a specialized audience,'' quipped David Chasman, vice-president of production at M-G-M/UA. ''Now there's been a dramatic change. The sheer number of people in America, 230 million, means there is an art house audience sizable enough to interest the studios.''

POSSIBLY nothing haunts a mother-to-be more than the fear that her baby will not be normal. That fear becomes a nightmarish reality for 2 to 3 percent of the 96,000 New Jersey women who give birth each year. Although some birth defects are as minor as an extra tab of skin or a small blemish, others involve major cosmetic flaws or physical or mental handicaps. In 1981, more than 200 newborns died of congenital defects, one-fourth of New Jersey's infant mortality.

IN the continuing controversy over whether the Shoreham nuclear power plant should go into operation, public relations specialists and lobbyists have become almost as ubiquitous as nuclear physicists and technical experts. The Long Island Lighting Company has been courting public opinion on Shoreham since it announced plans to build the reactor nearly 15 years ago; Suffolk County is something of a newcomer to the fray. In part, county officials say, this is because the county did not become an opponent of the plant until recently, having remained officially neutral during the 1960's and 1970's. The county began formulating its position last year, when hearings on a final operating license for the plant began. Over the years, the climate surrounding nuclear energy changed, with much of the enthusiasm of the 1960's giving way to apprehensiveness and skepticism that followed events at the Three Mile Island plant in Pennsylvania nearly four years ago.

NEW HAVEN WHAT do you do when many of the people you meet think you are trying to prevent progress? Members of groups that promote the preservation of historic buildings and sites in Connecticut decided recently that they have to change their image if they want more support for their cause from neighbors and governmental leaders. Representatives of historic preservation groups met last Saturday in a conference at the Yale Law School. They agreed that whether they hailed from large cities or rural towns, they should take steps to educate others about their projects and goals. ''In Haddam, we are perceived as an elitist WASP organization trying to preserve our own kind,'' said George Creeger of the Greater Middletown Preservation Trust.

Spurred by a 25 percent investment tax credit, according to the United States Treasury Department, $800 million was spent last year nationwide reconstructing historic temples, churches, mansions and other old buildings. By 1985, such spending is expected to rise to $2 billion.