Also known as Sorites paradox the argument is that no useful distinction can be made between two extremes because drawing the line somewhere between them appears arbitrary. Without a definable point at which one extreme transitions into the other there can be no discrimination between the two.

An oft used example is the heap of sand. A heap of sand does not exist, so the argument goes, because if I begin with a single grain of sand and continue to add grains of sand there is no obvious point at which a heap has been created.