Second Call for Papers Sixth International Conference on the Nature and Ontology of Spacetime So far representatives of 17 countries have submitted abstracts When: 11-14 May 2020 Where: Albena (famous Black Sea resort near Varna), Bulgaria Website: http://www.minkowskiinstitute.org/conferences/2020/ Contact: 2020conference@minkowskiinstitute.org The Scientific Organizing Committee invites papers from physicists, philosophers of physics and philosophers on any topic related to the nature and ontology of spacetime. As there is no main theme of the sixth spacetime conference a number of special sessions have been suggested by colleagues (http://www.minkowskiinstitute.org/conferences/2020/call.html): - Nature of time - Flow of time; Becoming (continuation of the Special Session on Becoming and the panel discussion at the Second Hermann Minkowski Meeting on the Foundations of Spacetime Physics on Wednesday, May 15, 2019) - Is spacetime a real (physical) four-dimensional entity or a mathematical concept? - Open Questions in Spacetime Physics - The controversy over Relativistic Mass - The problem with the gravitational energy-momentum pseudotensor in general relativity - should we have a closer look at the fact that the mathematical formalism of general relativity does not yield a proper tensor of the gravitational energy-momentum? - What is the difference between matter and geometry in general relativity, semi-classical gravity, and quantum gravity? - Do Black Holes Actually Exist? - Is there a conflict between relativity and quantum mechanics? - Quantum Gravity: Where do we stand? Depending on the number of colleagues participating in a special session, we plan to publish a volume with the talks presented at the session, which will include constructive criticism and the replies of the authors. Contributed papers in the form of extended abstracts of between one and two pages should be emailed to 2020conference@minkowskiinstitute.org by February 28, 2020. Submissions will be reviewed and sending of notification of acceptance will start on February 17, 2020 (for the abstracts submitted by the original deadline January 31, 2020). Scientific Organizing Committee: Dennis Dieks (Utrecht University) Mauro Dorato (University of Rome Three) George F. R. Ellis (University of Cape Town) Robert Geroch (University of Chicago) Eleanor Knox (King's College London) Vesselin Petkov (Minkowski Institute, Montreal) Steven Savitt (University of British Columbia) Anguel Stefanov (Bulgarian Academy of Sciences) James Owen Weatherall (University of California, Irvine) Christian Wuethrich (University of Geneva)