 There are obvious structural similarities between desert claims and claims about entitlement. In typical examples of each sort, someone is said to deserve (or be entitled to) something from someone on some basis. However, there is an important difference between the concepts of desert and entitlement. As the terminology is used here, desert is a more purely normative concept, while entitlement is a sociological or empirical concept. If some social or legal institution is in place in your social group, and that institution has a rule that specifies some treatment for those who have some feature, and you have the feature, then you are entitled to that treatment. Thus, for example, suppose that when the customer purchased a certain item, he received a legally binding written guarantee from the seller. The guarantee specified that if the item should turn out to be defective, the seller would either replace the item or refund the money that the buyer had spent for the defective item. In such a case, if the buyer satisfies the conditions stated in the guarantee, and the purchased item is indeed defective, the buyer is entitled to the refund or replacement. 