Also known as:mistake of fact · ignorance of fact · mistake or ignorance of fact · mistake of fact defense
Written by attorneys · grounded in primary & secondary sources — see below
2 senses
1
An error concerning an existing fact that defeats an actor's privilege to use defensive force when the other party's privilege rests on a reasonable mistake not caused by the actor's fault.
2
Sense 1
1
Sense 1
An error concerning an existing fact that defeats an actor's privilege to use defensive force when the other party's privilege rests on a reasonable mistake not caused by the actor's fault.
Sources & Authorities· 1 source
Select any source to read its text and confirm it supports the definition.
Restatements
Examples
Sense 2
2
Sense 2
An error of fact or law that affected specific terms of a donative instrument and that may be corrected by reformation when clear and convincing evidence establishes both the mistake and the transferor's true intention.
Sources & Authorities· 1 primary source
Select any source to read its text and confirm it supports the definition.
An error of fact or law that affected specific terms of a donative instrument and that may be corrected by reformation when clear and convincing evidence establishes both the mistake and the transferor's true intention.
Each sense below has its own examples, sources, and questions.
2
Self-Defense Privilege Unaffected by Third-Party Error
Idris Ives swung a bat at Isla Ireland after she approached him aggressively on a dark street. Ireland was in fact a plainclothes officer lawfully attempting an arrest, yet Ives honestly believed she was a mugger because a bystander had shouted a false warning. Because the officer's privilege rested on her lawful authority rather than any mistake induced by Ives, the court held that Ives could not claim self-defense and remained liable for battery.
Third-Party Warning Destroys Defensive Privilege
A store owner drew a firearm on an approaching customer after a bystander yelled that the customer was armed and dangerous. The customer was in fact an off-duty officer executing a lawful arrest. Because the officer's privilege rested on actual authority rather than any mistake induced by the owner, the court denied the owner the defense of self-defense.
Frequently Asked3
When does a mistake of fact provide a complete defense to a criminal charge?+
A mistake of fact is a defense if it negates the purpose, knowledge, belief, recklessness, or negligence required to establish a material element of the offense. The defense applies even if the mistake is unreasonable provided it actually prevents formation of the required mental state.
Supporting sources
Does the defense require the mistake to be reasonable?+
No. An honest mistake suffices when the offense requires purpose or knowledge. Reasonableness becomes relevant only when the offense is defined in terms of negligence or recklessness and the mistake itself must be evaluated under that standard.
Supporting sources
How does mistake of fact interact with self-defense privilege in tort?+
An actor is not privileged to defend against force the other is privileged to inflict except when the other's privilege rests on a reasonable mistake of fact not caused by the actor's own fault. A mistake induced by a third party does not create the privilege.
Supporting sources
Examples4
Will Reformation for Omitted Account
Ivan Ivanov's will left his donor-advised fund at Helping Hands to a charity. He had opened a second identical account after the will was signed and always referred to both as his charitable holdings. Clear and convincing evidence showed the omission resulted from a mistake of fact about which accounts existed. The court reformed the will to include the second account and carry out Ivanov's demonstrated intention.
Trust Reformation for Misdescribed Beneficiary
Ivy Ibarra created a trust naming her niece as remainder beneficiary. Drafting notes proved she had intended her nephew instead, and the error arose because the attorney confused the two names during execution. Clear and convincing evidence established both the mistake of fact and Ibarra's true intention. The court reformed the trust instrument to substitute the correct beneficiary.
Reformation After Attorney's Name Confusion
A settlor instructed counsel to name her nephew as remainder beneficiary of a revocable trust. The attorney instead inserted the name of the niece because of a clerical mix-up in the family records. Clear and convincing evidence proved both the mistake of fact and the settlor's actual intention. The court reformed the instrument to substitute the nephew.
Reformation of Misdescribed Trust Remainder
A testator's pour-over will left the residue to a trust that named the wrong sibling because the scrivener transposed two similar names. Clear and convincing evidence showed both the mistake of fact and the testator's true intention. The court reformed the will to carry out the intended disposition.
Frequently Asked1
Can a will be reformed when a mistake of fact affected its terms?+
Yes. A donative document may be reformed if clear and convincing evidence shows that a mistake of fact or law affected specific terms and reveals the donor's true intention. Direct evidence contradicting the plain text may be considered.
…classes: [¶] .... .... .... .... .... .... .... [¶] Three — Persons who committed the act or made the omission charged under an ignorance or mistake of fact, which disproves any criminal intent." [^maj-5]: Since Mayberry , supra , the Courts of Appeal have struggled with the issue of when an instruction on reasonable and good faith but…