20 The Quantum Structure of Space and Time
S. Weinberg In the story about Einstein and Bohr’s famous argument, what both-
ers me is that Bohr is supposed to have won by invoking general relativity.
But what if general relativity were wrong? Then, does that mean quantum
mechanics would be inconsistent? I suspect, although I have not studied
the debate in detail, that the issue actually arises only within a framework
in which there is a gravitational redshift and it does not really depend on
the validity of general relativity.
P. Galison That seems right. That is to say, what is required for the clock speed
to depend on the gravitational potential is much less than the full structure
of general relativity.
G. Gibbons Basically, it is energy conservation and nothing more. In fact in that
little thought experiment, you are not using gravity, it could be any force
that is holding up the clock. I think it is completely decoupled from general
relativity, I agree entirely with what Weinberg has said.
P. Galison Rhetorically what Bohr profits from is that he is referring back to
Einstein’s own work.
G. Gibbons It is certainly true that Einstein discovered the gravitational redshift,
but it is decoupled from general relativity.