  This paper has three main aims: first, to give a pedagogical introduction to
Noether's two theorems and their implications for energy conservation in
general relativity, which was a central point of discussion between Hilbert,
Klein, Noether and Einstein. Second, it introduces and compares two proposals
for gravitational energy and momentum, one of which is very influential in
physics: and, so far as I know, neither of the two has been discussed in the
philosophical literature. Third, it assesses these proposals in connection with
recent philosophical discussions of energy and momentum in general relativity.
  After briefly reviewing the debates about energy conservation between
Hilbert, Klein, Noether and Einstein, I give Noether's two theorems. I show
that Einstein's gravitational energy-momentum pseudo-tensor, including its
superpotential, is fixed, through Noether's theorem, by the boundary terms in
the action. That is, the freedom to add an arbitrary superpotential to the
gravitational pseudo-tensor corresponds to the freedom to add boundary terms to
the action without changing the equations of motion. This freedom is fixed in
the same way for both problems. I also review two proposals for energy and
momentum in GR, of which one is a quasi-local alternative to the local
expressions, and the other builds on Einstein's local pseudo-tensor approach. I
discuss the recent philosophical literature on the conservation of energy and
momentum in general relativity, and I assess and compare the two proposals in
the light of this literature: especially, in light of questions about
diffeomorphism invariance and background-independence.
