Editing General covariance (section)

== Remarks ==
The relationship between general covariance and general relativity may be summarized by quoting a standard textbook:<ref name="GravitationP431">{{cite book | title=[[Gravitation (book)|Gravitation]] | author-link1=Charles W. Misner|author1=Charles W. Misner|author-link2=Kip S. Thorne|author2=Kip S. Thorne|author-link3=John Archibald Wheeler|author3=John Archibald Wheeler | year=1973 | publisher=Freeman | isbn=0-7167-0344-0 | page=431}}</ref>

{{Quote|Mathematics was not sufficiently refined in 1917 to cleave apart the demands for "no prior geometry" and for a geometric, coordinate-independent formulation of physics. Einstein described both demands by a single phrase, "general covariance". The "no prior geometry" demand actually fathered general relativity, but by doing so anonymously, disguised as "general covariance", it also fathered half a century of confusion.}}

A more modern interpretation of the physical content of the original [[principle of covariance|principle of general covariance]] is that the [[Lie group]] GL<sub>4</sub>('''R''') is a fundamental "external" [[symmetry]] of the world.  Other symmetries, including "internal" symmetries based on compact [[Group (mathematics)|groups]], now play a major role in fundamental physical theories.