Sir

Although I share John Horgan's concern about the misrepresentation of science by the current US administration and others, expressed in his Book Review of Seth Shulman's Undermining Science (“Dark days at the White House” Nature 445, 365–366; 2007), he and other commentators need to distinguish clearly between science and ethics in their arguments. It is bad science to claim that reducing environmental protection will not have adverse effects on rare species, for example, but the decision whether we should protect rare species or not is an ethical one.

With regard to research on embryonic stem cells, I know of no one who denies that there would be at least some scientific insights and medical benefit from such research. However, the real question with regard to stem-cell research is whether the potential medical benefit and scientific knowledge outweigh any harm done to the embryo. The answer depends strongly on the value assigned to the embryo, which is not a scientific question. Thus, instead of being an example of science versus anti-science, this is a case of competing ethical claims. Replacing an advocate of stem-cell research on the President's Council on Bioethics with someone morally opposed to it reflects support for an ethical position (although the fact that this particular example involved replacing a biologist with a political philosopher does also raise the possibility that science was getting less say).

By invoking science as supporting a particular position on ethical questions, which science cannot directly answer, critics are making an error of logic similar to the one made by the Bush administration itself.