Ascertain whether the constant of action is universal across all quantum fields (Action-Universality)

Ascertain whether Action-Universality holds—namely, whether the constant of action used to quantize the gravitational field is the same Planck constant h used for matter fields—and develop a principled account of the metaphysical nature of fundamental constants that can decide this universality, given its implications for path-integral quantization and for coupling gravity to matter.

Background

In the analysis of quantum gravity as an effective field theory, the author identifies a hidden assumption required to link the breakdown scale to the Planck length: that all quantum fields share the same constant of action (Action-Universality). While h appears naturally in the path integral for matter fields, extending this to gravity—and especially to gravity coupled to matter—implicitly assumes the universality of h.

The author emphasizes that deciding the truth of Action-Universality requires an account of the metaphysical nature of fundamental constants. Without such an account, it remains unresolved whether the same constant of action should appear in the quantization of gravity, which affects whether the breakdown scale aligns with the Planck length.