Sir

Last week in Correspondence (Nature 418, 367; 200210.1038/418367b) you published the views of seven subcommittee members of Germany's science council, the Wissenschaftsrat, about the European Spallation Source (ESS).

The council released a statement on nine large-scale facility projects in July this year. These include the ESS, which was evaluated by the subcommittee in a meeting last December. The draft version of their final statement prepared by the Wissenschaftsrat's secretariat was based on the conclusions agreed at that meeting. In April, all subcommittee members were given three weeks to comment on this draft version. With some modifications and additional comments, all except one endorsed the statement on the relevance of the scientific case for the ESS, which some of them are now disputing.

The Wissenschaftsrat considered the overall importance of each of the nine projects in terms of science policy on the basis of each subcommittee's findings. It goes without saying that a science-policy assessment can come to different conclusions from those of a disciplinary evaluation. Funding decisions will be based on the Wissenschaftsrat's comprehensive statement which takes several subcommittees' reports into account.

As chair of the Wissenschaftsrat, I was surprised to read that a statement recently agreed on by all members of a subcommittee except one is now drawn into question by several members. I would find it more helpful if the debate focused on the scientific merit of the ESS project.