What condition must be met for a promise to be enforceable despite the absence of consideration?

For a promise to be enforceable in the absence of consideration, substantial detrimental reliance by a party on the promise must be present. This concept is grounded in the doctrine of promissory estoppel, which allows a party to recover on a promise, even though it is not supported by consideration, if that party has reasonably relied on the promise to their detriment.

In essence, if one party makes a promise that another party relies on to take significant actions or incur expenses, the law may enforce that promise to prevent an unjust result, despite the lack of traditional consideration. This reliance must be substantial and reasonable, as it creates an expectation that the promise will be fulfilled.

The other options do not address the necessary legal framework for enforcing a promise without consideration. A written agreement, while sometimes helpful for clarity and enforceability concerning other contracts, does not negate the requirement for consideration on its own. Promises made under perfunctory conditions do not inherently imply enforceability; instead, they lack the substance for a binding contract. Lastly, involving a third party does not necessarily establish the enforceability of a promise; the focus remains on the actions and reliance of the party who accepted the promise.