What principle asserts that you cannot be unjustly enriched at the expense of someone else?

The principle that asserts you cannot be unjustly enriched at the expense of someone else is known as "Quantum Meruit." This legal doctrine allows a person to recover the value of benefits they have conferred onto another party, when it would be unjust for the other party to retain those benefits without compensating them. Essentially, it seeks to prevent one party from being unfairly enriched while another suffers a loss, highlighting the importance of fairness and equity in contractual relations.

Understanding Quantum Meruit is crucial in many business and legal scenarios, particularly when formal contracts may be absent or when the terms of a contract are unenforceable for some reason. This principle helps maintain balance and fairness in dealings, ensuring that no party takes advantage of the efforts or contributions made by another without compensation.