t was the parade of the seven psychiatrists, finally, that proved to be too much for their peers. They came to the witness stand in full regalia, each carrying expert testimony about the psyche of John Hinckley.

"Process schizophrenia," said one. "Narcissistic personality disorder," said another. "Sad mood disorder," said a third. "Sane." "Insane." "Responsible." "Not responsible."

As their opinions of the man who shot the president were relayed to the judge, jury and people, it began to sound like dialogue out of a modern Drs. Gilbert and Sullivan.

It wasn't the first time that psychiatrists had played partisan roles: shrinks for the defense versus shrinks for the prosecution. Nor was it the first time that a "not guilty by reason of insanity" verdict had stirred up such a volatile public response.

But in the Hinckley trial, two professions--one that tries to understand human behavior and the other that has to judge it--had met on the turf of the insanity defense. It was, ultimately, psychiatric credibility that had been trampled, and so it was the psychiatrists who went on the defense.

The American Psychiatric Association came out last week with its own statement on insanity pleas. It told the lawmakers that they should tighten the rules so that an insanity defense would only be used in the case of major mental illness, when, for example, a psychotic is basically out of touch with reality. They went on to suggest that it should be made harder for those criminally insane to be released from mental institutions.

But what was notable about this modest law-and-order posture was not just what the psychiatrists said about the legal system. It was what they suggested in public about themselves.

They reported, in essence, that psychiatry is an uncertain art. You cannot read a human mind the way you can read an X-ray. You cannot predict human behavior the way you can predict chemical reactions.

They went so far as to warn the public not to expect too much of psychiatrists. Criminal insanity was something that, ultimately, a jury had to decide. The decision about whether a violent patient was "cured"--healthy enough to be released into the community-- was something to be reckoned by lay people as well as doctors.

Much of this was sensible--one might even say, sane. Psychiatrists are not in the same business as lawyers. The courtroom, as one psychiatrist described it, is often a three-ring circus where the lawyers are ringmasters and psychiatrists their clowns. Yet it occurred to me how rarely we hear a collection of designated experts asking us to be skeptical about their expertise. How rarely we hear professionals inviting us to share their power.

On the whole, our experts are only too happy to suggest they have cornered the market on truth and alone can deliver it. We've seen that with economists, energy researchers, scientists.

We've watched the authorities on Depo-provero, Oraflex, and Agent Orange duel across congressional hearing-room floors like characters in an Errol Flynn movie. We've seen the environmentalists with studies unsheathed, flashing statistics at each other. We've seen the swashbuckling planners with projection tables and charts pointed at each other.

And very rarely has any one of them admitted what the psychiatrists suggested this week: that the "evidence is usually not sufficiently clear-cut to prove or disprove many . . . facts 'beyond a reasonable doubt.'"

I suppose psychiatry is different. It is by nature, by our human nature, the most inexact and individual science. But it also has a particular mission--to help us confront myths and self-deceptions. One of our myths is that they can make our decisions, our verdicts, for us.

In this statement about the insanity plea, the psychiatrists have done what they are supposed to do: encourage people to act for themselves. They've said something about relationships: that experts with their knowledge and limits are, at best, helpers, not decision- makers. We have to be the jury, the partners.

That's not a bad model for a society that vacillates wildly between worshipping and distrusting its experts. It's not even bad therapy.