  What is meant by the circumstances having changed so that the initial injustice “has been superseded?” The meaning seems to be that, although the members of Q acted unjustly when they first shared P’s water hole, they do not act unjustly now when they share P’s water hole; and this is because circumstances have changed. In the changed circumstances the members of P and Q are now joint owners of the waterhole. It might be asserted that this follows from one of the conditions Locke laid down as necessary for taking something as property, the Lockean proviso, as Nozick famously put it (Nozick 1974: 175; Locke 1689: Book II, 5, sec 27). According to the proviso, the water hole used to be P’s waterhole when circumstances were such that it was permissible for P to make it his property. But circumstances have changed so that it is no longer permissible for P to make the waterhole his exclusive property. The present circumstances make the waterhole the joint property of P and Q.