  We might begin by noting that a tree and rock, say, can be distinguished in terms of their different properties. We might then go further and insist that this also forms the basis for ascribing individuality to them. Even two apparently very similar objects, such as two coins of the same denomination or so-called identical twins, will display some differences in their properties – a scratch here, a scar there, and so on. On this account such differences are sufficient to both distinguish and individuate the objects. This undergirds the so-called ‘bundle’ view of objects, according to which an object is nothing but a bundle of properties. In order to guarantee individuation, no two objects can then be absolutely indistinguishable, or indiscernible, in the sense of possessing exactly the same set of properties. This last claim has been expressed as the Principle of Identity of Indiscernibles and it ensures the individuality of the objects that fall under its scope; we shall return to it below.