  I discuss various aspects of background independence in the context of string
theory, for which so far we have no manifestly background independent
formulation. After reviewing the role of background independence in classical
Einstein gravity, I discuss recent results implying that there is a conflict in
string theory between manifest background independence and manifest duality
invariance when higher-derivative corrections are included. The resolution of
this conflict requires the introduction of new gauge degrees of freedom
together with an enlarged gauge symmetry. This suggests more generally that a
manifestly background independent and duality invariant formulation of string
theory requires significantly enhanced gauge symmetries.
