In Roman law, a quasi contract (also known as a “contract implied in law”) is a legal concept that refers to obligations that arise when there is no express agreement between two parties. This type of contract is based on the principle of natural justice, which dictates that individuals should be held accountable for their actions and that no one should benefit from another`s loss.

Quasi contracts can arise in a variety of situations, such as when one party has received a benefit from another party without their consent, or when two parties have entered into an incomplete or ambiguous agreement. In these cases, a court may intervene and create a quasi contract to ensure that both parties are treated fairly.

One key element of a quasi contract is that it must be based on a legal obligation, rather than a mere moral or ethical obligation. For example, if a person voluntarily pays for another person`s medical bills, this may be a moral obligation, but it does not give rise to a quasi contract. In contrast, if a person pays for another person`s bills under the mistaken belief that they are legally obligated to do so, this may be considered a quasi contract.

Another important concept in quasi contract law is unjust enrichment. This occurs when one party has obtained a benefit from another party without compensating them for it. In these cases, the court may create a quasi contract to ensure that the party who received the benefit pays the other party a fair amount in compensation.

Quasi contracts are an important part of Roman law and continue to play a role in modern legal systems. They are often used in cases where there is no explicit contract between two parties, but where it is clear that one party has received a benefit from the other. By creating a quasi contract, the court can ensure that both parties are treated fairly and that natural justice is upheld.