1. Germany; A.Schirrmacher@deutsches-museum.de.
2. This paper began as a presentation to the Quantum Theory Centenary at Berlin in Dec 2000 and has benefitted from comments by Olivier Darrigol, Michael Eckert, Klaus Hentschel, Dieter Hoffmann, Ulrich Majer, Tilman Sauer and Erhard Scholz. I thank the editors M. Norton Wise and J.L. Heilbron for editing and condensing.
3. The following abbreviation is used: HP, Hilbert Papers, Manuscript Department, Niedersachsische Staats- und Universitatsbibliothek, Gottingen, Cod. Ms. D. Hilbert.
4. 1
5. David Hilbert, "Vortrag Munster," HP, 586, 5f