 In the Kantian philosophy of P. F. Strawson (1959, 1966), this framework of necessity is taken in a more common-sense and realist spirit. The world must possess such enduring objects for it to be intelligible for us—indeed, for us to be part of it, for we are essentially stable bodies amongst other stable bodies. The important point for both Strawson and Kant is that there must be substances for there to be a coherent empirical, spatio-temporal world. Substance has become a formal concept of central importance—that is a concept with a special central role in the structure of our conceptual scheme—rather than being the name for certain kinds of important things in the world. This distinction, however, is one that has to be handled carefully, especially within a realist Kantian framework, such as Strawson provides. This should become clear below when we discuss Wiggins’s theory, which is both Aristotelian and Strawsonian. Nevertheless, it gives ground for adding the seventh of the marks of substance mentioned in the Introduction, namely that substances are those enduring particulars that give unity to our spatio-temporal framework and individuation and re-identification of which enables us to locate ourselves in that framework.