Reply to Gao's “On Uffink's criticism of protective measurements”

Gao (this issue) presents a critical reconsideration of a paper I wrote (Uffink, 1999) on the subject of protective measurement. Here, I take the occasion to reply to his objections. In particular, I retract my previous claim to have proven that in a protective measurement, the observable being measured on a system must commute with the system's Hamiltonian. However, I do maintain the viability of the interpretation I offered for protective measurements, as well as my analysis of a thought experiment proposed by Aharonov, Anandan and Vaidman against Gao's objections.