The public debate over nuclear arms reductions is, to a dismaying extent, an argument between the know-nothings and the experts.

A growing number of citizens, perhaps typified by the participants in the recent Ground Zero campaign, acknowledge their ignorance of much technical detail but insist, nevertheless, that somebody has to make a move toward sanity before we destroy the world. The experts acknowledge the sincerity of the public feeling but point out that a naive push for arms reduction could increase the likelihood of a nuclear conflagration by tempting the Soviets with our weakness.

No matter what the impassioned speakers at the rallies say, no matter what the public-opinion polls show, the experts always answer, in effect: it ain't that simple.

Now comes a thoroughly accredited expert who says it is that simple. Adm. Noel Gayler (Ret.), former commander-in-chief of U.S. forces in the Pacific and former director of the National Security Agency, has come up with a nuclear arms-reduction proposal that speaks to the concerns of both the naive and the experts. Writing in the April 25 issue of The New York Times Magazine, he puts compelling flesh on the skeletal idea of another expert, George F. Kennan, former ambassador to the Soviet Union, who has called for a 50 percent reduction in nuclear devices by both sides.

He avoids, as Kennan did not, the wrangling over how to count and equate weapons, how to ensure compliance and all the other technical objections that the experts keep raising. Here is the heart of his proposal:

"Let each side turn in (to a specially created international commission) an equal number of explosive nuclear devices. Let each side choose the weapons it wishes to turn in, whether missile warheads, bombs or artillery shells. Each weapon would count the same as one device."

The verification problem evaporates at once. "A nuclear device is uniquely identifiable and can be counted without error when turned in." Furthermore, "since each side chooses the weapons it wishes to turn in, there can be no problem about what is fair; and since all explosive fission devices count equally, we have no arguments about how the weapons should be classified."

But wouldn't each side simply surrender its nuclear junk, the obsolete devices it would likely have scuttled in any case? Here is the real beauty of the Gayler proposal:

"Self-interest will make each side turn in its more vulnerable weapons. This is good. As we now stand, both the United States and the Soviet Union have relatively vulnerable land-based strategic missiles, mounted in fixed silos. It would be logical for both sides to start giving up these weapons, while retaining their less vulnerable strategic bombers and virtually invulnerable nuclear-armed submarines. In this way, the temptation of either side to fire first in time of crisis, lest it lose its weapons to an enemy who attacks first, will be reduced. The 'hair-trigger' character of the nuclear forces, the most dangerous aspect of the present situation, will be eliminated."

There's more: with the most vulnerable missiles no longer in the picture, each side's highly accurate and powerful weapons-- the Soviet SS18 and the American MX-- that are most threatening to the other side's fixed silos would tend to lose their value. As Gayler puts it, these superweapons would "be deprived of their 'counterforce' targets --the land-based strategic missile force of the other side, which they now threaten with destruction in a preemptive first strike."

The result, he predicts, would be increased reliance by both sides on their least vulnerable forces and, as a consequence, less chance of war-triggering accident.

"We can start," he suggests, "by each turning in a relatively small number of weapons--say 50--to test the system and establish confidence. From there, we should proceed on an agreed schedule to a very large reduction-- say 10,000 devices each. Again, the idea is to compel each side to choose to retain only a small number of weapons in a strategic reserve."

Gayler's idea makes near-perfect sense. It would eliminate the major part of the arms race that involves weapons systems whose major purpose is to protect other weapons systems and, as a consequence, enhance the security of both sides.

And it would tend to disabuse both sides of the notion that there is any salvation in an attempt to gain nuclear superiority--the notion that is behind the U.S.-Soviet arms race. Gayler quotes, with hearty approval, a recent Foreign Affairs article by Kennan, Robert McNamara, McGeorge Bundy and Gerard Smith, in which they warned:

"Deterrence cannot be safely based forever on a doctrine which more and more looks to people of the alliance like either a bluff or a suicide pact."