What legal principle suggests that a promisor may be bound by a promise even in the absence of a valid contract?

The concept of promissory estoppel is particularly significant in contract law because it holds that a promisor can be legally bound to a promise, even if a formal contract doesn’t exist, provided certain conditions are met. This legal principle serves to prevent injustice when one party relies on the promise of another party to their detriment.

For promissory estoppel to apply, there generally needs to be a clear and definite promise made by the promisor intended to induce action or forbearance. The promisee must then rely on that promise in a reasonable manner, leading to a situation where failing to enforce the promise would cause significant harm or injustice. This doctrine essentially prioritizes fairness and reliance over strict contractual obligations.

In contrast, estoppel on its own can refer to a broader range of situations where a party is prevented from arguing something contrary to a claim they have previously made. Implied contracts arise from actions or circumstances rather than verbal or written agreements, while express contracts are those where the terms have been clearly articulated by the parties involved. Therefore, the focus on reliance and preventable harm is what distinctly characterizes promissory estoppel compared to these other concepts.