Philosophical
Sorites Paradox (Heap Paradox)
When does a heap of sand stop being a heap?
Overview
A paradox arising from vague predicates, questioning at what point a change in quantity results in a change in quality or category.
If you remove one grain of sand from a heap, it's still a heap. Continue this logic, and eventually you're left with one grain - which isn't a heap. But at what point did it stop being a heap?