On the philosophical foundations of measurements in general relativity

In this paper, first, the question of what a measurement is in General Relativity is tackled; then, some foundational problems it involves are analysed. In particular, by recalling what a measurement is in general, we will try to precisely define what it is in General Relativity. Then, we will analyse, by means of a suitable foundational problems do not arise owing to the gauge invariance or the correlation among the measuring observers but owing to the principle of equivalence.