Philosophy of Physics Seminar (Thursday - Week 8, HT26)

Abstract: From 1907 onwards, Albert Einstein searched for a theory that would both extend the relativity principle from inertial to accelerated motion and also provide a new theory of gravity to replace Newton’s theory. In the summer of 1912 this search entered a new stage: Einstein realised that the right kind of theory would need to feature field equations that have an energy-momentum tensor as a source and a metric tensor as a gravitational potential. Widespread accounts of the subsequent development suggest a race that reached its finishing line with Einstein finding what we now call the Einstein field equations in late November 1915, the set of equations that many now see as the beating heart of the general theory of relativity (GR). In this talk, I shall argue that Einstein’s own perspective was markedly different, in that he saw GR much more as a project, indeed a building project, in which the field equations feature as a capstone resting on a series of pillars and foundation stones, in such a way that he regarded the precise form of the field equations as much less fixed than many later relativists would. I shall present Einstein’s framework theory of 1913, followed by six theories of gravity that Einstein considered between 1913 and 1919, each of them featuring different field equations, each of them fascinating in their own right. I will compare the different elements and aspects of these theories, arguing that each of them is worthy of detailed conceptual analysis and of comparing their respective merits.

Registration: If you do not hold a university card, please contact the seminar convenor or admin@philosophy.ox.ac.uk at least two working days before a seminar to register your attendance.