It is one of the most repeated responses whenever the subject of time comes up. OK, point taken. But a time interval is (represented by) a unitary matrix, and therefore can be written as exp(iK) for K being Hermitian. So it sounds like although a time (interval) is not directly measurable, it is (theoretically) directly calculable from measurements, and is a real number. But many measurements have at least one step in their derivation which is actually a calculation, such as when we measure velocity. So is the identification of " observable" with "Hermitian" using the former term only in a technical sense but no longer one corresponding to our experience?