Preserving the past: it could help to ensure the future

It was a small story. The British government (the recent wire-service report said) has informed the Greek government that the Elgin marbles - removed from the Parthenon by a British ambassador, Lord Elgin, early in the 19th century - would continue to reside at the British Museum. The Greek government, calling it ''a matter of moral and cultural principle,'' says it will continue pressing for their repatriation.

An old dispute, it is one small tributary of an issue that has become a substantial river: the desire, felt in nation after nation, to preserve a ''cultural heritage.'' From the Buddhist temple of Borobudur in Indonesia to the Mayan structure at Tikal in Guatemala, from the 4,500-year-old ruins of Mohenjo-Daro in Pakistan to the 19th-century palace of Sans Souci in Haiti, interest is mounting in the restoration of monuments that define the culture of the people they represent.

Such interest has long been felt: The Romantic poets and painters, celebrating picturesque ruins, were neither the first nor the last to define their artistry through past monuments. Over the last two decades, however, the cultural-heritage movement has suddenly surged. The successful effort by 51 countries to save the Egyptian monuments of Nubia from the rising waters behind the Aswan Dam was launched in 1960. In 1965 the International Council of Monuments and Sites was founded. In 1972, the United Nations Educational, Scientific, and Cultural Organization (UNESCO) adopted the World Heritage Convention. In the United States alone there are some 32,000 historic sites listed on the National Register of Historic Places, itself only 18 years old.

So it is not surprising that a recent conference in Washington, sponsored by UNESCO and the Smithsonian Institution, addressed the question ''Why Preserve the Past?'' An obvious query, it led to some obvious answers phrased in orotund rhetoric. The really interesting questions, however, went almost unasked. Why this sudden interest, during the last third of the 20th century, in preserving the world's cultural heritage? What does it tell us about ourselves?

Here, too, there are obvious answers. Since the end of World War II, the breaking up of colonial empires has produced a number of independent nations, each trying to establish its own identity. As global communication has spread pictures of their ancient monuments, international interest has increased. And as air travel has grown, travelers find they can savor a foreign culture more by examining its monuments than lying on its beaches. Press further, however, and another answer emerges, both alarming and promising. Why the sudden concern over the past? Because, say some observers, of the threat of nuclear war.

An alarming response? Yes, if it arises from a fear of the future that longs to bury its head in the past. The preservation movement, in fact, is the flip side of the current fascination with the future - evidenced in the popularity of books and articles produced by the futurists. They reassure us, after all, that there will be a future. Monuments reassure us that human enterprise has survived centuries of change and can continue to do so. The intense desire for such reassurance, however, bespeaks an uneasy sense of the present.

But that very desire also has its promise. Those who built the great monuments - Buddhist, Indian, Christian, or whatever - believed their work would endure. What gave them such confidence? Can we who study these monuments comprehend something of their faith? They, too, sometimes felt threatened by catastrophe. Can we learn anything from their experience?

The resounding ''Yes'' from the preservationists suggests that we can, indeed , arrive at a world so respectful of its multitudinous cultures - and so dotted with the carefully preserved works of its past - that the price of destructive conflict becomes too great to contemplate. It is sometimes said that a nuclear exchange could only be started by a nation with nothing to lose. Will not the world, then, be measurably safer in proportion as every nation recovers its own sense of culture and respects its own monuments too deeply to risk their loss?

That, in 1984, may be the real reason for preserving the past. Seen that way , cultural preservation is no longer simply a gambit of the tourist industry or an excrescence of nationalist fervor. It becomes a central and positive force for good - uniting nations, enriching self-awareness, and perhaps even helping to lessen the threat of nuclear conflict.