Changes

Today some physicists are working on a reconciling general relativity with [[quantum theory of gravitymechanics]] , and determining how gravity fits with the three subatomic forces of nature (the "theory of everything"), such as . Two of the more commonly studied attempts at this reconciliation are [[string theory]] and [[loop quantum gravity]]. Critics increasingly point out that [[string theory]] and [[loop quantum gravity]] are largely untestable and unfalsifiable, and thus potentially unscientific under the principles of science advanced by [[Karl Popper]].<ref>See, for example, ''Not Even Wrong'', by Peter Woit</ref>.