California Civil Jury Instructions (CACI)
330. Affirmative Defense—Unilateral Mistake of Fact
[Name of defendant] claims that there was no contract because [he/she/it] was mistaken about [insert description of mistake]. To succeed, [name of defendant] must prove all of the following:
1. That [name of defendant] was mistaken about [insert description of mistake];
2. That [name of plaintiff] knew [name of defendant] was mistaken and used that mistake to take advantage of [him/her/it];
3. That [name of defendant]’s mistake was not caused by [his/her/its] excessive carelessness; and
4. That [name of defendant] would not have agreed to enter into the contract if [he/she/it] had known about the mistake.
If you decide that [name of defendant] has proved all of the above, then no contract was created.
New September 2003; Revised April 2004
Directions for Use
If the mistake is one of law, this may not be a jury issue.
This instruction does not contain the requirement that the mistake be material to the contract because the materiality of a representation is a question of law. (Merced County Mutual Fire Insurance Co. v. State of California (1991) 233 Cal.App.3d 765, 772 [284 Cal.Rptr. 680].) Accordingly, the judge would decide whether an alleged mistake was material, and that mistake would be inserted into this instruction.
Sources and Authority
- The Civil Code provides that consent is not free when obtained through duress, menace, fraud, undue influence, or mistake, and is deemed to have been so obtained when it would not have been given but for such fraud or mistake. (Civ. Code, §§ 1567, 1568.)
- Civil Code section 1576 provides: “Mistake may be either of fact or law.”
- Civil Code section 1577 provides the following definition of mistake of fact: Mistake of fact is a mistake, not caused by the neglect of a legal duty on the part of the person making the mistake, and consisting in:
1. An unconscious ignorance or forgetfulness of a fact past or present, material to the contract; or,
2. Belief in the present existence of a thing material to the contract, which does not exist, or in the past existence of such a thing, which has not existed.
- Civil Code section 1578 defines mistake of law:
Mistake of law constitutes a mistake, within the meaning of this Article, only when it arises from:
1. A misapprehension of the law by all parties, all supposing that they knew and understood it, and all making substantially the same mistake as to the law; or,
2. A misapprehension of the law by one party, of which the others are aware at the time of contracting, but which they do not rectify.
- “It is settled that to warrant a unilateral rescission of a contract because of mutual mistake, the mistake must relate to basic or material fact, not a collateral matter.” (Wood v. Kalbaugh (1974) 39 Cal.App.3d 926, 932 [114 Cal.Rptr. 673].)
- “A mistake need not be mutual. Unilateral mistake is ground for relief where the mistake is due to the fault of the other party or the other party knows or has reason to know of the mistake. . . . To rely on a unilateral mistake of fact, [the party] must demonstrate his mistake was not caused by his ‘neglect of a legal duty.’ Ordinary negligence does not constitute the neglect of a legal duty as that term is used in section 1577.” (Architects & Contractors Estimating Service, Inc. v. Smith (1985) 164 Cal.App.3d 1001, 1007–1008 [211 Cal.Rptr. 45], internal citations omitted.)
- To prevail on a unilateral mistake claim, the defendant must prove that the plaintiff knew that the defendant was mistaken and that plaintiff used that mistake to take advantage of the defendant: “Defendants contend that a material mistake of fact—namely, the defendants’ belief that they would not be obligated to install a new roof upon the residence—prevented contract formation. A unilateral mistake of fact may be the basis of relief. However, such a unilateral mistake may not invalidate a contract without a showing that the other party to the contract was aware of the mistaken belief and unfairly utilized that mistaken belief in a manner enabling him to take advantage of the other party.” (Meyer v. Benko (1976) 55 Cal.App.3d 937, 944 [127 Cal.Rptr. 846], internal citations omitted.)
- “Failure to make reasonable inquiry to ascertain or effort to understand the meaning and content of the contract upon which one relies constitutes neglect of a legal duty such as will preclude recovery for unilateral mistake of fact.” (Wal-Noon Corporation v. Hill (1975) 45 Cal.App.3d 605, 615 [119 Cal.Rptr. 646].) However, “[o]rdinary negligence does not constitute the neglect of a legal duty as that term is used in section 1577.” (Architects & Contractors Estimating Service, Inc. v. Smith, supra, 164 Cal.App.3d at p. 1008.)
- Neglect of legal duty has been equated with “gross negligence,” which is defined as “the want of even scant care or an extreme departure from the ordinary standard of conduct.” (Van Meter v. Bent Construction Co. (1956) 46 Cal.2d 588, 594 [297 P.2d 644].)
1 Witkin, Summary of California Law (10th ed. 2005) Contracts, §§ 256–275
17 California Forms of Pleading and Practice, Ch. 215, Duress, Menace, Fraud, Undue Influence, and Mistake, §§ 215.50–215.57, 215.141 (Matthew Bender)
9 California Points and Authorities, Ch. 92, Duress, Menace, Fraud, Undue Influence, and Mistake, § 92.90 et seq. (Matthew Bender)
27 California Legal Forms, Ch. 77, Discharge of Obligations, § 77.350 (Matthew Bender)
1 Matthew Bender Practice Guide: California Contract Litigation, Ch. 8, Seeking or Opposing Equitable Remedies in Contract Actions, 8.24
1 Matthew Bender Practice Guide: California Contract Litigation, Ch. 16, Attacking or Defending Existence of Contract—Mistake, 16.08, 16.13–16.16, 16.18