March 13, 1983

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.