Identifying a correct candidate for the final theory among quantum gravity approaches

Ascertain whether any current quantum gravity framework—such as superstring theory/M-theory, loop quantum gravity with spin foam models, or causal set theory—constitutes the correct candidate for a true final theory that exhaustively describes fundamental physical reality.

Background

The paper compares several contenders for a final theory of quantum gravity, including superstring/M-theory, loop quantum gravity and spin foam models, and causal set theory. It emphasizes that these approaches are rooted in abstract mathematical structures potentially far from direct observation and notes the philosophical challenge of relating such structures to emergent physical spacetime. The author explicitly states uncertainty about whether any existing approach is the correct final theory.