Relativistic Ether: Unfinished Conceptual Change

Abstract

Einstein’s initial attitude towards electromagnetic ether in special relativity was deeply disrupted by general relativity. In this paper we analyze Einstein’s different arguments against electromagnetic ether in the frame of special relativity. We then study his reasons for postulating a gravitatory ether in general relativity. After comparing the properties and functions of the traditional electromagnetic ether with those of the new relativistic ether, we conclude that a conceptual change has occurred, because the term “ether” has undergone a change of meaning. However, we also show that the new ether still retains many properties and functions characteristic of the old electromagnetic ether.