This paper addresses the relationships between Arthur S. Eddington, former director of the Cambridge Observatory (1914-1944), with the International Astronomical Union. It is demonstrated that the Union was related to every major moment in Eddington’s scientific career. New historical elements are brought forward, in the last section of the paper, to demonstrate Eddington’s action in favour of German colleagues during the Second World War.

Under what conditions should epistemic institutions (institutions that provide policy-relevant scientific advice) be integrated into international legal institutions – for example, the Conference of the Parties to the United Nations Framework Convention on Climate Change? Following work in law and economics on the theory of the firm, this article argues that where states will not implement environmental policies absent a collective decision to do so, greater hierarchical control of epistemic institutions by legal institutions may be necessary to ensure the credibility and availability of a usable scientific record. Hierarchy creates credibility because it allows all states necessary for cooperation in the legal institution to oversee the production of the scientific record that provides the basis for international legal rules. Hierarchy thus enhances the effectiveness of international law as a coordination tool, even at the expense of the autonomy of the scientific process. By contrast, where collective action is not necessary because states will unilaterally regulate an environmental problem once scientific uncertainty has been reduced, epistemic and legal institutions should be fragmented to ensure the unbiased production and dissemination of scientific information. In such situations, the credibility of the scientific record is demonstrated by decentralized adoption of science-based regulation.