 There are two important things to notice about this response. The first is this. In conceding that Einstein’s indirect method for determining, say, the position of Niels’ system does not mechanically disturb that system, Bohr departs from his original program of complementarity, which was to base the uncertainty relations and the statistical character of quantum theory on uncontrollable physical interactions, interactions that were supposed to arise inevitably between a measuring instrument and the system being measured. Instead Bohr now distinguishes between a genuine physical interaction (his “mechanical disturbance”) and some other sort of “influence” on the conditions for specifying (or “defining”) sorts of predictions for the future behavior of a system. In emphasizing that there is no question of a robust interaction in the EPR situation, Bohr retreats from his earlier, physically grounded conception of complementarity.