N. 3 - 21 aprile 2001 - Giano Bifronte

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"This word ether has changed its meaning many times in the
development if science [...] Its story, by no means finished, is continued
by relativity theory."
It seems interesting to quote even the following passages by Eistein,
where he somehow admits the rational necessity of the ether, that is to
say, the necessity of conceiving a space which cannot be thought of but
endowed with physical properties:
"There is an important argument in favour of the hypothesis of the
ether. To deny the existence of the ether means, in the last analysis,
denying all physical properties to empty space."
"The ether hypothesis was bound always to play a part even if it is
mostly a latent one at first in the thinking of physicists."
So we have seen the description of one of the main themes of
Einstein's research, going on through a complex route which Kostro
aims to carefully reconstruct, as the Index of his book clearly shows:
Introduction
Chap. 1 - Einstein's views on the ether before 1905
Chap. 2 - Einstein denies the existence of the ether (1905-1916)
Chap. 3 - Einstein introduces his new concept of the ether (1916-
1924)
Chap. 4 - Development of Einstein's ether concept (1925-1955)
Chap. 5 - Physical meaning of Einstein's relativistic ether
Appendix - Original quotations
Bibliography
[the Bibliography lists more than 250 items!]
We could stop here this presentation, but we feel necessary to add
some more words discussing the opinion, shared by the author, that
general relativity could be truly conceived of as a theory of a dynamical
ether. Indeed, it is perhaps appropriate to emphasize that the general
opinion about Einstein discarding the ether is in some sense not
absolutely groundless, since a relativistic ether - as we must theorize
the physical space according to the relativistic conceptions of space and
time - is quite different for instance from the Descartes's ether. This