General Principle of Relativity
Section Eighteen
Einstein says that his general principle of relativity claims this:
All bodies of reference K, K', etc., are equivalent for the description of natural phenomena (formulation of the general laws of nature), whatever may be their state of motion. (p. 69)
Is there any reason for expecting that this may hold? Apparently, the answer seems to be "No", since accelerated motions provide a counter-example.
We must recall that Newton tried to show, by similar arguments, that the absolute motion can be detected by empirical means (see my commentary on Scholium). However, Einstein intends to show that this counter-example can be overcome, and that the the general principle of relativity holds. We have to examine how this is possible; we have to notice the ambiguity of the phrase "equivalent for the description of natural phenomena", in the preceding quotation.
Last modified, May 7, 2002. (c) Soshichi Uchii
suchii@bun.kyoto-u.ac.jp