Do we pay enough to have a glass of water when we're thirsty? And to have the latest smartphone? And when I'm going to make a gift or a donation to an individual or an institution, can I determine the right value of what I'm giving or donating? And again: what do we feel is really worrying about climate change? And what is troubling us about the migratory movements of entire populations? And what do we really know about our use of currency? If we go deeper into the subject (indeed the competence of the medical and social sciences) of the needs of the human being, the economy allows us to give a fair answer to these questions. Being able to measure one's own needs and those of others allows us to act rationally in the face of these questions and many others that also concern the search for the right gratification in human and social behavior.