Eddington’s critical thoughts on general relativity: insights in the light of modern cosmology

The article recalls some of the critical remarks and thoughts of Sir Arthur Stanley Eddington on general relativity published by him in two culturally rich volumes—Space, Time and Gravitation (STG) (1920) and The Mathematical Theory of Relativity (MTR) (1923). When one looks back on these remarks, which were considered as only of historical importance in relativity, it can be seen how relevant they are in the context of modern cosmology. Eddington’s ambitious connection between the cosmical constant and elementary particles, nature of the relativistic field equation and microscopic behaviour of spacetime metric is realised to be precursors of current attempts in realising a union between gravity and the quantum. An attempt to quantify some of his remarks on the cosmical constant is presented. Remarks on nature of space and matter in the scale of elementary particles are reviewed in the light of present understanding of quantum gravity. Whereas the consideration of the cosmical constant has deeply penetrating meaning for classical and quantum cosmology, his interpretation of the geodesic structure of the world leads to the relational philosophy. Progress in some of his ideas is discussed in the context of modern cosmology. It is inferred that Eddington’s relativistic philosophy of matter and space seeded the germ of new physics and cosmology being envisioned today.