What do you suppose those 12 jurors who pronounced John W. Hinckley Jr. insane would have made of Ludwig van Beethoven (1770-1827)? Is it possible that a contingent of psychiatrists could have proved to them that old Ludwig was a bit of a fruitcake? He lived like one, and with the composition of his colossal Third Symphony he began conceiving as music sounds that had never been heard in any concert hall before.

One of the many ponderables left in the wake of Hinckley's successful insanity plea is that today's psychiatrists can never attribute the stupendous music of Beethoven to Beethoven. He was one of the greatest geniuses ever to tread this earth. Yet rather than confront the majesty of his deeds, our psychiatrists must attribute them to environment, heredity and other deterministic phenomena as diagnosed by them. The composer of "Missa Solemnis" is not to be held responsible for his art. That is the world they see. Dwell on it --a world without extraordinary men, a land without human nature! Why does the shrink not simply wander off and swig the hemlock?

It is my belief that a psychiatrist is no more useful to our judicial process than a snake charmer. Our system of law believes in moral accountability and free will. Psychiatrists believe human action is deterministic. In Arthur Fergenson's apt epithet, they are Calvinists without God.

Moreover, the criteria supporting their occult judgments conform to no scientific standards. They are mere speculations. Sometimes the speculations are weird and engaging. More often they are prosaic; hence, their potent ability to infect the minds of dullards. One of the great myths of the 20th century is that psychiatry is a science. It is not. It is the medium of gossips, dilettantes and psychic peeping Toms.

But if the Hinckley decision is partially the consequence of bogus science receiving bogus esteem, it is even more the consequence of a decadent judicial process. The potentates who countenance the legal dogmas that absolved Hinckley have wandered far from the purposes of law.

I cannot state with certitude the condition of Beethoven's mind while he composed his masterpieces. Nor can I ascertain beyond doubt Hinckley's state of mind when I saw him fire exploding bullets into the head of Jim Brady and the chest of the American chief of state. Yet without doubt I would have voted him guilty, and according to Stuart Taylor Jr., reporting on the trial in The New York Times, my guilty vote would have been expected.

Notwithstanding the broad dimension of the insanity defense set forth in Judge Parker's instructions, Taylor reports that almost everyone, "at least in legal circles," expects jurors to "have enough common sense not to apply (the judicial instructions) literally to such fundamentally unprovable issues as that of legal sanity." Unfortunately, these were conscientious jurors. They took the judge at his word.

The insanity defense should be abolished as some states have already done. It should exist only to establish whether a defendant was mentally capable of intending a criminal act. Establishing sanity demands too much. We should no longer rely on the hyprocisy described by Taylor to protect us from criminals.