The concept of 'measurement' becomes so fuzzy on reflection that it is quite surprising to have it appearing in physical theory at the most fundamental level... does not any analysis of measurement require concepts more fundamental than measurement? And should not the fundamental theory be about these more fundamental concepts?

"Quantum Mechanics for Cosmologists" (1981); published in Quantum Gravity (1981) edited by Christopher Isham, Roger Penrose and Dennis William Sciama, p. 611 - 637