As any of a number of self-realization centers and encounter groups on this coast could tell you, expressing one's innermost thoughts is good for the soul and the digestion. So why has this therapeutic activity worked out so badly for David Stockman?

We seem to suffer recurrent national episodes of Truth and Consequences. Public officials let their genuine thoughts escape from their mouths, and all hell breaks loose. In just the last few weeks, the leading military officer on the president's national security staff, the chief of staff to the governor of California and finally OMB Director Stockman have all performed this ritual.

Perhaps there is a way to ease the pain of such incidents in the future, and for no other reason than to ensure the mental health of our political leaders, even encourage more bursts of candor.

Any reporter can tell you that most politicians, no matter how politic, still suffer from the human urge to say out loud occasionally what they are actually thinking. Given enough time and the right atmosphere, they will succumb to the temptation. Stockman's indiscreet remarks occurred over the course of several months of conversations, so long a time that he probably forgot some of the more troublesome things he said. Out here, we recently had B. T. Collins, the governor's chief of staff, confess during several lengthy conversations with a reporter from the Los Angeles Times that Gov. Edmund G. Brown Jr. did not wash his hair often enough and was often out exploring some intellectual Uranus while "people with real problems" waited to see him.

Is this sort of talk really so bad? Whom would we rather have setting public policy: a man who feels the urge to openly tell the truth occasionally or a man so tightly wound that his innermost thoughts are only revealed in tape recordings released by court order? Several human civilizations--even those with the strictest standards for public conduct and utterances--have developed devices to allow the release of inner passions in special circumstances where all would agree to ignore what happened. The English country weekend and the American office Christmas party fall into that category. Why could we not have an annual conversational bacchanal for public figures? Why not, at least one day a year, take the generous rules of legal immunity enjoyed by some confessing criminals and extend them to politicians?

Some might suggest either Harry Truman's or Barry Goldwater's birthday as an appropriate date for the celebration of unrestrained public expression, but I think we are going to have to insist on April 1. For this to work, even with legal immunity, truth tellers are going to have to be able to claim that whatever they have said falls possibly into the realm of satire or fiction, even if quite the opposite is the case. April Fool's Day is perfect for that.

Why, after all, should political reporters be able to turn their most libelous and unprintable stories into profitable novels, while the politicians they write about have no similar outlet?

Our history might have been very different if such a National Self-Expression Day had caught on earlier. George Romney might have gone on to be president even after expressing his honest feeling that he had been "brainwashed" about Vietnam. Gen. John Singlaub, too quick to express his dismay at the threat to the Korean peninsula, might still be leading American troops there. If we begin planning now, next April 1 could be celebrated with appropriate ceremonies. Soap boxes could be put up in public squares all over the country.

But during any presidency in Washington, celebration of the principle that self expression is good for the soul would be most appropriate with a special ceremony on the White House lawn, where we could hear a few remarks from the vice president--any vice president--of the United States.