IT'S STILL too early to assess the substance of the summit. But it's not too early to remark on the conditions of controlled isolation and secrecy that Jimmy Carter, as host, has imposed on the Camp David proceedings. Speaking as journalists itching for news, we're up the wall. But speaking as citizens and students of diplomacy, we're delighted. No manipulation of external conditions can ensure a good result.But if there is any chance at all to make progress toward peace, it can only be enhanced, we believe, by the direct and undistracted focus that the privacy at Camp David allows.

That's what is so compelling about the silence from Camp David. It is not as if Menachem Begin or Anwar Sadat or, for that matter, Jimmy Carter, is the shy retiring sort. All three have betrayed a natural political instinct to play to one or another grandstand in the past, to make statements for political effect, to engage in simple posturing. But for that, you do not retire to the privacy of the Maryland hills. That they have done so is the best evidence that they are serious men, with an immense shared interest in making as much as they can of the summit opportunity. One has only to think of the popular currents that either Mr. Begin or Mr. Sadat could summon up by a word, and of the way their separate statements could be played against each other, to be thankful that the Camp David talks, by mutual consent, are being held in the equivalent of a soundproof room.

Any day now, if it hasn't happened already, we expect someone to make the point that the secrecy Mr. Carter is enforcing at Camp David is precisely what he criticized Henry Kissinger for and promised not to indulge in himself: "Open diplomacy" was supposed to be Jimmy Carter's thing. It's a superficial point.

It is not, after all, that the principals have not had ample opportunity in the past to make their viewpoints known. It is not that they (and Mr. Carter) will not be able as soon as the summit ends to play to their various publics. It is not that they are eluding the pressures that compel them to satisfy their separate constituencies.

The relevant distinction here is between process and result. It was the president's entirely correct judgment that the peace process in the Mideast was suffering from a surfeit of openness. In the Mideast, public exchanges were sharpening differences, exacerbating popular emotions, blocking real progress, while, in Washington, policy-makers and the different interest groups were sparring. In this context, private exchanges were imperative.

Any result of the Camp David discussions, on the other hand, must be made public. The publics demand it. They cannot be expected to support an outcome that is not laid out fully before them.

No doubt other occasions will arise when the United States or its diplomatic partners will feel that a certain amount or kind of publicity, issued in midstream, has its uses after all. The way this summit works out will probably have a good deal to do with determining whether Camp David becomes a procedural model. Meanwhile, we take the American-Egyptian-Israeli readiness to conduct quiet diplomacy as proof of their determination to move toward peace.