The fact that a Giffen good might exist:

Question

Quizplus · Accepted Answer

The law of demand states that as the price of a good increases, the quantity demanded decreases, while as the price of a good decreases, the quantity demanded increases. The existence of a Giffen good, which is a rare exception to this law where the quantity demanded actually increases as the price increases, does not negate the law of demand. It simply represents a unique case in which the usual relationship between price and demand is reversed.

The Fact That a Giffen Good Might Exist