As the world changes, the Institutes adapt: the internationalization of science
The First World War marks the start of a period of disruption, which will continue after the conflict, between scientists from the Allied Powers and those from the Central Powers. Since the Solvay Conferences are by nature international, the repercussions are serious.
During the conflict, Ernest Solvay refuses to put the buildings of the Institutes located in Parc Léopold at the disposal of the German occupying forces, a refusal that is not well received by the German authorities. While the Belgian industrialist continues to repeat that ‘science is international above all’, the German scientists fear that the Belgians will refuse any future collaboration. Indeed, relations are very tense. The German army is accused of having committed atrocities on Belgian soil during the invasion. Among the scientific community, the destruction of Leuven’s university library is seen as a truly traumatic experience.
Most German scientists deny any responsibility. One manifesto in particular is going to crystallize the contrasting opinions: ‘To the Civilized World’, better known as the ‘Manifesto of the Ninety-Three’. In this pamphlet, 93 intellectuals and scientists, among whom Nobel Prize winners but also members of the Scientific Committee of the Solvay Institute for Physics, deny all the accusations levelled at the German Army and declare their solidarity with their military forces. The pamphlet causes a genuine shock in Belgium.
Paul Héger, at the time a close friend of Ernest Solvay, a former rector of Université libre de Bruxelles and the director of the IIPS, is among the disillusioned. He expresses his indignation to Hendrik Lorentz, the president of the Scientific Committee of the International Solvay Institute for Physics, a renowned Dutch physicist whose country remained neutral during the war.
In March 1916, Max Planck, a signatory of the ‘Manifesto of the Ninety-Three’, tries to justify himself and expresses his regrets to Hendrik Lorentz. The latter mediates between Franco-Belgian and German scientists during but also after the war. Sensitive to the tragedy that has struck Belgium, Hendrik Lorentz insists on his neutrality and tries to iron out the disagreements between the physicists of both camps. Thanks to Solvay’s agreement, his role as a conciliator makes it possible to avoid the dissolution of the Institute for Physics after the First World War.
