# Equivalence principle

1. ### princeton118

33
It is said the Einstein Equivalence Principle is the heart of GR , and for this principle, the gravitational field can be convincingly described by the structure of the spacetime. But what puzzles me is how can this principle do it. It just includes WEP, LLI and LPI. How can these imply the gravitational field should be described by the metric thoery?

Thanks!