The physical basis of the standard theory of general relativity is examined
and a nonlocal theory of accelerated observers is described that involves a
natural generalization of the hypothesis of locality. The nonlocal theory is
confronted with experiment via an indirect approach. The implications of the
results for gravitation are briefly discussed.Comment: LaTeX file, no figures, 12 pages. To be published in: Proc. 25th
Johns Hopkins Workshop "2001: A Relativistic Spacetime Odyssey" (World
Scientific, Singapore