Diminishing marginal utility is neither necessary nor sufficient for downward sloping demand. Yet upper-division undergraduate and beginning graduate students often presume otherwise. This paper provides two simple counter examples that can be used to help students understand that the Law of...

Diminishing marginal utility (DMU) is neither necessary nor sufficient for downward-sloping demand. Yet, upper-division undergraduate and beginning graduate students often presumeotherwise. This paper provides two simple counter-examples that can be used to help students understand that the Law...