Suppose we concede that the new atheists are right, and no true, honest scientist could be anything other than an atheist. If that is true, the teaching of science itself becomes unconstitutional.An act becomes unconstitutional only when the Supreme Court actually so rules, despite how Brown or anyone else (including those on the Supreme Court) believes they might rule in the future.
It's completely implausible that the Supreme Court would ever actually rule this way — if they can rule that "In God We Trust" doesn't establish a religion, they can rule that teach scientific truth does not violate the Establishment clause.
The current legal standard regarding Church-state separation is the Lemon test*, which establishes the following criteria:
- The government's action must have a secular legislative purpose;
- The government's action must not have the primary effect of either advancing or inhibiting religion;
- The government's action must not result in an "excessive government entanglement" with religion.
It would be unconstitutional to teach science only if the primary effect were to inhibit religion, but the primary effect of science is to understand truth about the world. The secondary effects are legally irrelevant.
Finally even if this assertion were true, then so what? Bring it on! The U.S. Constitution is not holy writ, and if the Supreme Court were to be so appalling stupid (even by the standards of American conservatism) as to prohibit the teaching of science under the Establishment Clause, then the Establishment Clause would have to be repealed.
Brown is just talking out of his ass. Quelle suprise.