→Causation versus correlation: superfical counterexamples
Note that, as discussed in the apparent counterexamples, if the prices of substitute inputs increases ''more'', demand for the given input might increase even as the price increases.
==Causation versus correlation:
It is important to understand that the law of demand discusses the effect of a change in price on the quantity demanded for the good. Thus, it does not predict that an increase in price is always accompanied by a decrease in quantity demanded. Rather, it says that, [[ceteris paribus]], an increase in price is responsible for a decrease in quantity demanded.