If you imagine that the Supreme Court was sufficiently severe in striking down (7-2) Louisiana's law requiring the teaching of ''creation science'' when evolution is taught, you imagine wrong.

It was technically sufficient for the court to conclude that the law violated the three-prong test that detects ''establishment'' of religion. But neither the majority nor the minority spoke sensibly about ''creation science,'' which holds that the physical universe and life within it appeared suddenly by the act of a supernatural creator and have not changed substantially since appearing.

The case hardly constituted a close call. Louisiana's law impaled itself on all three prongs of the ''establishment'' test. A law comports with the establishment clause if it has a secular purpose, if it neither advances nor inhibits religion and does not involve excessive government entanglement with religion. Louisiana's law required government to stuff a religious dogma into school curricula.

But Justice Brennan, writing for the majority, did not question the scientific nature of ''creation science.'' He even suggested the law would have been less flawed (it could have been presented as an attempt ''to maximize the comprehensiveness'' of scientific instruction) if it had ''encouraged the teaching of all scientific theories about the origins of humankind,'' rather than just two. Two? ''Creation science'' is a scientific theory? It is, surely, constitutionally relevant that the phrase ''creation science'' is an oxymoron.

The dogma packed into the word ''creation'' is incompatible with a defining attribute of a scientific theory. Such a theory must be open to refutation. ''Creation scientists'' count themselves scientists because they are interested in evidence that calls into question particular hypotheses about the mechanism of evolution. But their dogma is neither based on, nor vulnerable to, scientific scrutiny of the world.

In a dismaying dissent, Justice Scalia, joined by Chief Justice Rehnquist, suggests that it is unfair to infer a non-secular purpose to Louisiana's protection of ''creation science.'' Scalia takes seriously the legislature's words about ''protecting academic freedom.'' But no one wants to protect academic freedom by requiring the teaching of flat-earth doctrines in geography classes or alchemy in chemistry classes. The difference is that no one reads those doctrines into the Book of Genesis.

Scalia says the views of the court ''about creation science and evolution are {or should be} beside the point. Our task is not to judge the debate about teaching the origins of life, but to ascertain what the members of the Louisiana Legislature believed.'' Scalia's formulation is nonsense because ''creation science'' is nonsense on stilts. Again, there is no scientific ''debate'' about whether evolution is a fact. The debate is about how evolution happens.

Scalia, with serene impartiality between science and pseudoscience, says Louisiana has a right to give students whatever ''scientific evidence'' there may be against evolution. Good grief.

Stephen Gould, call your office. You are busy teaching biology, geology and the history of science at Harvard, but now you must head for the law school and combat science illiteracy.

Scalia finds praiseworthy the law's requirement that evolution be ''taught as a theory, rather than as proven scientific fact.'' That use of the word ''theory'' illustrates Gould's point that in the layman's vernacular, ''theory'' means ''less than a fact.'' But that usage is mistaken.

Facts are revisable data about the world. Theories are supposed to interpret facts. Evolution is a fact about which there are various explanatory theories. ''All dogs think in Latin'' is a theory for which there is no factual basis.

''Creation science'' is a theory for people who are only interested in facts that weigh against a rival theory. But as Gould has written, no scientist doubts the basic fact that life evolves. The uncertainties concern the mechanisms. When Scalia tries to make much of the fact that the original version of the Louisiana bill emphasized giving ''students a choice between scientific models,'' he is only documenting the confusion of Louisiana's legislators. But that does not change the fact that they were legislating a religious assertion disguised as a scientific inquiry.

There is poignancy in the plight of fundamentalists whose spiritual serenity is under siege from facts. It is for theologians to say what consequences the fact of evolution has for faith. But it is for every thoughtful citizen to say this: The bedrock of Western civilization is a willingness -- no, an eagerness -- to face and embrace facts. And if the facts inconvenience beliefs, too bad for the beliefs.