The International Human Rights Network of Academies and Scholarly Societies (http://www4.nas.edu/oia/oiahome.nsf/web/network) was created to address grave issues of science and human rights throughout the world. It aims to put into practice the professional duty of scientists and scholars to assist those colleagues whose human rights have been — or are threatened to be — infringed, and to promote and protect the independence of academies and scholarly societies worldwide. The basis of the network's activities is the universal declaration of human rights.

The network seeks to promote the free exchange of ideas and opinions among scientists and scholars in all countries and, thereby, to stimulate the development of collaborative educational, research and human-rights endeavours within academies and the institutions with which they are affiliated.

Moratoria on scientific exchanges based on nationality, race, sex, language, religion, opinion and similar factors thwart the network's goals. They would deny our colleagues their rights to freedom of opinion and expression; interfere with their ability to exercise their bona fide academic freedoms; inhibit the free circulation of scientists and scientific ideas; and impose unjust punishment. They would also be an impediment to the instrumental role played by scientists and scholars in the promotion of peace and human rights.

This statement, although that of a general principle with universal applicability, was prompted by a petition (see Nature 417, 1, 2002 and Nature 417, 221–222; 2002) that advocates a moratorium on all grants and contracts to Israel from European cultural and research institutions. The moratorium being advocated, although surely well-intentioned, is misguided and inevitably counterproductive.

We all look forward to an equitable solution to the crisis in the Middle East, with lasting peace and stability for both Israel and the Palestinian Authority. But the strongest impact of a moratorium would, rather than influencing Israeli policy-makers, seriously and unfairly harm our scientific colleagues in Israel — many of whom have actively promoted peace through collegial engagement and open communication among academic centres in the region.