The deflationist turn in recent philosophy of science has attracted attention, in part because it promises to end debates about scientific realism. In its recommendation that we leave metaphysics behind to look at practice, deflationism constructs itself as an end-of-philosophy philosophy, accepting knowledge and the evidence for it at face value. Meanwhile, recent work in philosophy, sociology, and history of science that has focused on practice has underscored problems of such an acceptance: much scientific knowledge is not straightforwardly about the natural world, and we would not want it to be. A concrete example from the history of comparative psychology illustrates this point, and illustrates the value of interpretive work on scientific knowledge. A focus on practice, then, does not end metaphysical discussion, but rather regrounds and reshapes it.