Can the reassessment of a historical debate contribute to the better understanding of an open philosophical question? The editors of this volume say that it can. The open question concerns the interpretation of quantum mechanics. The historical debate under review is the famous 1927 Solvay conference in Brussels. According to the received view, the standard Copenhagen interpretation was established as the canonical understanding of the new concepts brought about by quantum mechanics during that conference. The conference is remembered, above all, for the famous debate between Bohr and Einstein about the limits and understanding of the quantum uncertainty relations. Again and again, the received view has it, Einstein would come up with ideas for an experiment proving the inconsistency or incompleteness of the new quantum theoretical concepts. And again and again, Bohr would come up with a refutation of Einstein's challenge, proving the Copenhagen interpretation to be consistent and inevitable. But we really know about that debate between Einstein and Bohr only from the latter's own account, published some twenty years later in Paul Arthur Schilpp's Albert Einstein: Philosopher‐Scientist (Open Court, 1949). Contemporary accounts, most importantly a famous letter by Ehrenfest, are less explicit and more equivocal about the debate between Bohr and Einstein