Mistake

S.20 to S.22 govern mistake of fact and law; a bilateral mistake of fact essential to the agreement renders it void, while unilateral mistake and mistake of Indian law generally do not.

Mistake concerns an erroneous belief held by one or both parties about a fact or matter essential to their agreement. Unlike coercion, undue influence, misrepresentation, and fraud, which involve one party inducing another, mistake often involves both parties operating under a shared misapprehension, or one party's error unconnected to the other's conduct.

Legal Framework

Section	Act	Scope
S.20	Indian Contract Act, 1872	Agreement void where both parties are under a mistake of fact essential to the agreement
S.21	Indian Contract Act, 1872	A contract is not voidable merely because it was caused by a mistake as to any law in force in India
S.22	Indian Contract Act, 1872	A contract is not voidable merely because one party was under a mistake of fact, unless caused by the other's fraud

Bilateral Mistake of Fact: S.20

Where both parties to an agreement are mistaken about a fact essential to the agreement, the agreement is void.

Why void, not merely voidable: If both parties never actually agreed on the same subject matter or fundamental fact, there was never true consensus ad idem in the first place; the "agreement" is a legal nullity from the outset, not something either party can affirm or avoid at will.

Essential requirements:

Both parties must be mistaken, not just one.
The mistake must relate to a fact, not a matter of opinion or law.
The fact must be essential to the agreement, going to its very foundation, such as the existence of the subject matter, its identity, or the possibility of performance.

Unilateral Mistake of Fact: S.22

Where only one party is mistaken, the contract is generally not voidable on that ground alone.

Why: The law places the burden of accurate understanding primarily on each party themselves; permitting unilateral mistake to void contracts freely would undermine commercial certainty, since one party could too easily escape an unfavourable bargain by later claiming private error. An exception arises where the other party's fraud caused the mistake, since that shifts the analysis to the fraud doctrine itself.

However, courts have recognised limited categories where unilateral mistake still prevents a valid contract from forming at all, notably mistake as to the identity of the other contracting party, where identity was fundamental to the transaction, as in cases of fraudulent impersonation.

Mistake of Law: S.21

A mistake as to Indian law does not make a contract voidable, resting on the maxim ignorantia juris non excusat, ignorance of law is no excuse.

Why: Permitting mistake of domestic law to void contracts would create endless uncertainty, since every party could claim ignorance of the very law the contract operates under. However, a mistake as to foreign law is treated as a mistake of fact, since parties cannot be expected to know the law of a jurisdiction other than their own.

Illustrations

Bilateral mistake, void agreement: A agrees to sell a specific cargo of goods to B, both parties believing the ship carrying the cargo is still at sea. Unknown to either, the ship had sunk before the agreement was made, and the goods no longer exist. This is a bilateral mistake as to the existence of the subject matter, rendering the agreement void under S.20.
Unilateral mistake, contract not voidable: A buys a painting believing it to be an original, though the seller made no representation either way and the buyer never asked. If the painting turns out to be a reproduction, A's unilateral mistake, uninduced by the seller, does not make the contract voidable.
Mistake as to identity, no contract forms: A fraudster, posing as a well-known and creditworthy businessman, orders goods from a seller who extends credit believing he is dealing with that specific person. The identity of the buyer was fundamental to the seller's willingness to extend credit; no genuine contract arises with the impersonator, since the seller never intended to contract with him at all.

Recall Check

Why does a bilateral mistake of fact render an agreement void rather than voidable?
What is the general rule regarding a unilateral mistake of fact under S.22, and its exception?
Explain why mistake of Indian law does not excuse a party, but mistake of foreign law is treated differently.

Key Cases

Raffles v. Wichelhaus (1864) Raffles-v-Wichelhaus-1864 Issue: Whether a contract for the sale of cotton "to arrive ex Peerless from Bombay" was valid when two different ships named Peerless sailed from Bombay, and each party had a different ship in mind. Rule: Where parties are genuinely at cross purposes on an essential term, with no real meeting of minds, no valid contract arises. Held: No binding contract existed, since the mutual mistake as to which ship was intended meant the parties had never actually agreed on the same terms.

Cundy v. Lindsay (1878) Cundy-v-Lindsay-1878 Issue: Whether a contract arose where a fraudster impersonated a reputable firm to induce a seller to extend credit and dispatch goods. Rule: Where the identity of the other contracting party is fundamental to a party's willingness to contract, and that identity is fraudulently misrepresented, no contract arises with the impersonator at all. Held: No contract existed between the seller and the impersonator, since the seller intended to deal only with the genuine firm whose identity had been assumed.

Distinctions

Basis	Bilateral Mistake (S.20)	Unilateral Mistake (S.22)
Who is mistaken	Both parties	Only one party
Effect on contract	Void	Generally not voidable
Exception	None needed, void by operation of S.20	Voidable if caused by the other party's fraud, or where identity was fundamental
Rationale	No true consensus ad idem existed	Commercial certainty requires each party to bear their own errors

Flashcards

Q: What is the effect of a bilateral mistake of fact essential to the agreement, under S.20? A: The agreement is void.

Q: Is a contract voidable merely because one party made a unilateral mistake of fact? A: No, unless that mistake was caused by the other party's fraud.

Q: What is the effect of a mistake as to Indian law under S.21? A: The contract is not voidable; ignorance of Indian law is no excuse.

Q: How is a mistake as to foreign law treated? A: As a mistake of fact, since parties cannot be expected to know foreign legal systems.

Q: What did Cundy v Lindsay establish about mistaken identity? A: Where the identity of the contracting party is fundamental and fraudulently assumed, no contract arises with the impersonator at all.

Exam Scenario

A agrees to sell a specific antique vase to B for Rs. 5 lakh. Both parties believe the vase, kept in a warehouse, is intact. Unknown to either party, the vase had been accidentally destroyed in a fire the previous night, before the agreement was signed. B, on discovering this, demands either the vase or a refund with damages. Advise A on his position.

Approach: Identify this as a bilateral mistake of fact essential to the agreement: the continued existence of the specific subject matter, which neither party could have known was false at the time of contracting. Apply S.20 to establish that the agreement is void from its inception, since both parties were mistaken about a fact going to the very foundation of the sale. Conclude that A owes no contractual obligation to deliver the vase or pay damages for non-performance, since no valid contract ever came into existence, though B may be entitled to recover any advance payment already made, on grounds independent of contract.