Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 23 January 2020 doi:10.20944/preprints202001.0273.v1 The Theories of Relativity and Bergson’s Philosophy of Duration and Simultaneity During and After Einstein’s 1922 Visit to Paris C. S. Unnikrishnan Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005, India E-mail address:
[email protected] Abstract In 1922, Albert Einstein visited Paris and interacted extensively with an illustrious section of the French academia. In overfilled sessions at the Collège de France and the Sorbonne, Einstein explained his theories of relativity, and prominent physicists, mathematicians and philosophers listened, debated, questioned and explored facets of relativity. The 1922 visit had its echoes in the life and works of many who participated, particularly decisive for Ein- stein and the philosopher Henri Bergson. This essay examines that eventful visit, focusing on the physical and logical aspects of Bergson’s critique, with physics commentaries, linking prominent French physicists and mathemati- cians Langevin, Painlevé, Hadamard, Becquerel, Sagnac, and Kastler. I give particular attention to the logical and empirical accuracy of the physics issues involved, delineating Bergson’s exact reasoning for his philosophical enthusi- asm in Einstein’s theory and for the ensuing critique. Bergson’s philosophical stand on duration and simultaneity is reassessed in the context of later de- velopments in cosmological physics as well as the wealth of empirical data involving comparison of atomic clocks. Finally we are led naturally to a surprising completion of the philosopher’s program on universal time, du- ration and simultaneity, in harmony with the time of the physicist.