Spirituality – Metaphysics

Central Questions

Identity and Change

The Greeks took some extreme positions on the nature of change: Parmenides denied that change occurs at all, while Heraclitus thought change was ubiquitous: “[Y]ou cannot step into the same river twice.”

Identity, sometimes called Numerical Identity, is the relation that a “thing” bears to itself, and which no “thing” bears to anything other than itself (cf. sameness). According to Leibniz, if some object x is identical to some object y, then any property that x has, y will have as well. However, it seems, too, that objects can change over time. If one were to look at a tree one day, and the tree later lost a leaf, it would seem that one could still be looking at that same tree. Two rival theories to account for the relationship between change and identity are Perdurantism, which treats the tree as a series of tree-stages, and Endurantism, which maintains that the tree – the same tree – is present at every stage in its history.

Luc Paquin