MY COLLEAGUE wrote a characteristically thoughtful post on the non-binarism of scientific and faith-based belief systems. As it happens, my piece in this week's paper is about Tennessee's newly enacted law protecting teachers "from discipline for teaching scientific subjects in an objective manner". I spent a large part of last week discussing this bill with scientists and civil-libertarians, many of whom see the bill as a Trojan horse for the teaching of creationism and intelligent design; with the bill's supporters in Tennessee's legislature, who seem genuinely amazed that the bill has stirred controversy; and with a representative from the Discovery Institute, whence the bill's inspiration came. In this battle generally—that is, in the battle over whether humans evolved through natural selection or were created ex nihilo by God a few millennia back, and in the battle over whether the latter theory has a place in science classrooms—I side with the first camp.

But I found it difficult not to feel a measure of sympathy for the bill's sponsors, Representative Bill Dunn and Senator Bo Watson, both of whom seemed genuinely surprised by the furore it had caused. The original bill, which Mr Dunn sponsored and which passed Tennessee's House last year, said that "the teaching of some scientific subjects, including but not limited to biological evolution, the chemical origins of life, global warming, and human cloning, can cause controversy." Mr Watson amended that language out, but to many, the shadow remains. The problem, of course, is that there is a difference between subjects that "can cause controversy" for reasons external to science and subjects that are genuinely scientifically controversial. Evolution is the former but not the latter. That it may upset some people who take the Bible as literally true in every word is not science's problem, and ought not be the concern of science teachers. Mr Watson explained to me that distinctions such as this create great "teachable moments", and he is right, of course. He also pointed out that the bill changes nothing in Tennessee's curriculum, which includes evolution, and that it contains language expressly forbidding it from being used for religious instruction. Also true. If this bill is a Trojan horse for creationism, decades of court precedent have made sure it's a pretty weak one.

The problem is that it sows doubt in the wrong places. To be sure, there is continuing research into how people evolved, and Darwin's theory may not be correct in every particular (I wonder whether that's why the Discovery Institute so frequently uses "Darwinism" or "Darwinian evolution" rather than simply "evolution" or "evolution through natural selection": as a way to suggest that every quibble with Darwin amounts to a fatal flaw in the concept of evolution). There is also continuing research into gravity: how it works differently and unexpectedly on different bodies, but there is little clamour to throw out Newton's theory of gravity (oops: I spoke too soon). That is how science works: through observation, testing, empiricism. There is very little "this is how it is, in saeculum saeculorum", and a whole lot of "this is the best we can determine from observable evidence right now." There is relatively little certainty. On the other hand, significant amounts of observable, scientifically tested data and evidence support the theory of evolution through natural selection. The theory of ex nihilo creation cannot make the same claim.

None of this should be read as a denigration of religion. I notice I got a few comments on my post last week on Ross Douthat accusing me of loud-mouthed, aggressive atheism. For what it's worth, I am not an atheist. I do think, however, that religion is principally a matter of conscience, and that it should have far less direct influence on politics than it does in America today. That is a distinction worth preserving. It would seem to me entirely possible to be a faithful Jew, Christian, Muslim or other believer and still believe wholeheartedly in human evolution (that theory says nothing about the "unmoved mover"), just as it ought to be possible to be devout and still wish religion and politics to be kept as separate and far apart as possible. That is not just for the good of a multi-confessional polity, but also for the good of faith (faith as individual belief and as collective institutions) which cannot but be corrupted by too close a relationship with earthly power.