 Given Cohen’s opposition to ether theories, it is not surprising that he feels vindicated by Einstein’s special theory of relativity (Cohen 1898: 134; the passage appears in 1914–5 edition). In fact, Cassirer claims (1921: Ch.4) that Einstein’s general theory, which departs further from the “sensible” conception of matter by not separating matter from space and time, is a natural continuation of the idealism Cohen first articulated. 