Promise

A promise is a declaration or assurance that one will perform a specified action or that a particular outcome will occur. It represents a commitment by one party to another, often grounded in trust, social norms, or mutual expectations. Promises may be explicit, stated aloud or in writing, or implicit, inferred from conduct or past reliability.

The term comes from the Latin promissum, via Old French promesse, from pro- 'forward' and mittere 'to send.' The modern concept spans everyday social practice, law, ethics, and technology.

In law and contract theory, a promise can create an obligation when accompanied by mutual assent and consideration in a contract. Some promises are enforceable without a formal contract through doctrines such as promissory estoppel, which prevents a party from breaking a promise when another has relied on it to their detriment. A promissory note is a written, unconditional promise to pay a specified sum by a set date.

Oaths, pledges, and vows are solemn forms of promise with varied moral or ceremonial weight. Socially, keeping promises is often viewed as a core component of trust and reliability; breaking them can erode relationships and credibility.

In computing, a promise is an abstraction representing the eventual result of an asynchronous operation. A promise can be pending, fulfilled, or rejected, and provides mechanisms to chain operations and handle errors.

Promises appear in legal, ethical, and technological contexts as a basic form of commitment, illustrating how expectations about future actions shape behavior and institutions.