%0 Journal Article %T Equivalence Principle and Ether: Two Revolutionary Kernels of Einstein¡¯s General Relativity %A Salvo D¡¯agostino %J Advances in Historical Studies %P 240-253 %@ 2327-0446 %D 2016 %I Scientific Research Publishing %R 10.4236/ahs.2016.55019 %X Einstein¡¯s discovery of the Equivalence Principle is to be considered as the most fundamental concept at the origin of his General Relativity. I highlight that the ether problem is related with Enstein¡¯s conception of gravitational waves as a perturbation of the space-time curvature, formalized as a specific space-time process, and not as the effect of a whatever supporting medium. Quite differently, the nineteenth century field theory of gravitation supported by physicists such as Maxwell, Heaviside, and Hertz, was based on a search for substantial ether, and on a parallelism with Maxwell¡¯s theory of electromagnetic waves. The negative results of their theories proved that parallelism was a wrong approach. Einstein¡¯s genius superseded their approach by considering that it was not a matter of the ether¡¯s constitution, but of a fundamental change in the role and nature of physics. In my paper I refer to Einstein¡¯s different approaches to ether since his 1905 Special Relativity up to his 1950¡¯ views. I argue that his different attempts were symptoms of the difficulty of his revolutionary innovation. %K Einstein %K Maxwell %K Heaviside %K Hertz %K Cassirer %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=73182