Given the state of our relations with much of the Moslem world, this might seem an unlikely moment to mount a major exhibition on the arts and sciences of Islam, as the Museum of Natural History has just done.

The Smithsonian has gone all a-tiptoe through the cultures of the 800 million adherents of the way of Mohammad: A visitor will search in vain for any trace of politics in this sumptuous presentation of the youngest of the world's great monotheistic religions.

In fact the exhibit is a propaganda effort, but a disinterested one. Assembled by the all-American National Committee to Honor the Fourteenth Centennial of Islam, it's designed to remind us that the West is deeply indebted to Islam, and that in any case the Moslems aren't going to go away, so it behooves us to understand them better.

The Koran teaches that the material world is simply God's visible cloak, and so the pursuit of knowledge -- wherever it leads -- is devout and proper homage to Allah. It was Europe's great good fortune that Mohammad came along in the seventh century, because this enlightened attitude swept the Eastern world as the West was descending into the dreary and savage know-nothingism of the Middle Ages.

While we slept for centuries, Moslem scholars not only gathered and preserved what they found of wisdom in Greece and Rome, but also steadily advanced the frontiers of knowledge. So when Europe awoke in the Renaissance, it wasn't a millennium behind, only about 350 years -- which was how long it took us to "discover" the principle of blood circulation after the Moslems did.

A visitor unversed in Islamic history and culture may find the studied neutrality of the exhibition more than a little frustrating, since the relation of East to West is made clear only in the section on the sciences. The most valuable object is the historic scale near the entrance, which draws parallel time-lines that give a splendid sense of who was doing what, where and when.

The 250 objects range from prayer rugs to astrolabes, with a smattering of works by modern Moslem artists. Some are second- choice selections, made necessary by the unwillingness of museums and collectors to participate in the exhibition for political reasons, but the whole amounts to a gorgeous -- and thought-provoking -- array. THE ARTS AND SCIENCES OF ISLAM -- Through September 5 at the Museum of Natural History. Open 10 to 7:30.