"Monty Python's The Life of Brian," a film parody of Biblical extravaganzas, is the story of a man born the same moment and on the same street as Jesus and mistaken ever after for him. His every word, no matter how meaningless, is taken for Biblical writ by his followers, who then strain to figure out what in the world their false Messiah might have meant. We have among us a new Brian. For his name, see the first two words of the next paragraph.

Ronald Reagan. The other day, The New York Times dispatched a correspondent to a conference on space technology at Colorado Springs and had him ask various scientists what they thought of one of President Reagan's latest utterances -- his proposal to share the Strategic Defense Initiative (Star Wars) system with the Soviets.

"I just don't understand it," said William Rector, a vice president of the General Dynamics Corp. "It seems to run counter to everything else they are doing. It just doesn't make any sense." Other defense executives and scientists made similar remarks, except for Lt. Gen. James A. Abrahamson, who heads the government's Star Wars program. "I don't think the question is appropriate," he said. Oh. Pardon us.

As with the storied Brian, we feel obliged to treat Reagan's every remark on Star Wars as if it were rich with meaning even if no one has the foggiest notion what he is talking about. For instance, twice Reagan has said that he would be willing to share Star Wars technology with the Soviets. His last such comment was made in October, when he was asked by a BBC interviewer whether he would be willing to provide SDI "off the shelf" to the Russians. "Why not?" he responded.

Everyone else, though, can tell him why not. Because, as the Soviet in particular realize, elements of Star Wars can be used offensively as well as defensively. In conjunction with measures that could either overwhelm or fool a defensive Star Wars system, the new technology could conceivably be used to assist a nuclear first strike. We would not want an enemy to have that kind of technology nor, for that matter, would we want it to have the supercomputer necessary to make that kind of technology work.

The fact of the matter is there are many aspects of Star Wars as the president has explained them that no one but he understands. Only the president, for instance, thinks that Star Wars can ever be an invisible shield, sort of an umbrella, so that the Soviets can never rain missiles on our parade. Only the president talks of Star Wars as if it were only defensive. Only the president insists that Star Wars is nonnuclear when, manifestly, it is not. And only the president is confident Star Wars could result in the elimination of all nuclear weapons.

Star Wars is too important a concept, too upsetting to the Soviets and too destabilizing, for such imprecision in both language and, it seems, thought. At the moment, it appears to be the main stumbling block to a general arms reduction agreement with the Soviet Union. If it is worth risking arms reduction, then it is certainly worth defining.

That sort of proposal would hardly be popular at gatherings of defense scientists and executives. The reason none of them at Colorado Springs managed to work up a giggle at the president's statement is that they have all been bought off. Like tobacco state politicians who cannot, for the life of us, see how smoking and cancer are linked, the defense industry has little patience with Star Wars skeptics.

Soon that mentality will spread to the nation's major universities, as dependent as the defense industry on Pentagon research grants. The same holds for our European allies who, panting for American research dollars, think that Star Wars is a wonderful idea.

Monty Python's Brian was taken seriously because he was mistaken for the Messiah. The president is taken seriously because of his high office, his immense popularity and the even more immense amount of money he is willing to spend on his proposal. Unlike Brian, he is unmistakably who we think he is. That, alas, is the difference between farce and tragedy.