Legal Definitions - general non est factum

The legal term non est factum is a Latin phrase meaning "it is not my deed." It refers to a legal defense in contract law where a person claims that a document they signed is not legally binding on them because they were fundamentally mistaken about its character or contents, and this mistake was not due to their own negligence.

For this defense to succeed, two main conditions must typically be met:

• The person must have made a fundamental mistake about the *type* of document they were signing, or its core purpose, rather than just a mistake about some of its specific terms. For example, believing it was a petition when it was a guarantee, or a receipt when it was a deed of sale.
• The person must not have been careless or negligent in making this mistake. This often involves circumstances where the signer was vulnerable, such as being illiterate, visually impaired, elderly, or misled by another party.

The term "general non est factum" simply refers to the broad application of this defense principle. It means the defense is being invoked in its usual, comprehensive sense, rather than a specific, limited variation.

Here are some examples illustrating the concept of non est factum:

• Example 1: Elderly Individual Misled

  An elderly woman, who has limited vision and relies on her nephew for administrative tasks, is presented with a document by her nephew. He tells her it's a routine form to update her contact information for her bank. Trusting him, she signs it without reading the fine print. Later, she discovers the document was actually a deed transferring ownership of her house to her nephew. In this scenario, she could potentially argue non est factum because she fundamentally misunderstood the character of the document (believing it was an administrative update, not a property transfer) and her mistake was due to her vulnerability and reliance, not her own negligence.

• Example 2: Language Barrier and Deception

  A recent immigrant, who speaks very little English, is approached by a salesperson offering a "free trial" of a product. The salesperson presents a lengthy English document and quickly points to a signature line, assuring the immigrant that it's just to confirm receipt of the trial product. The immigrant signs, believing it's a simple acknowledgment. In reality, the document is a long-term, high-cost service contract. If the immigrant can prove they genuinely believed it was only a trial confirmation and were not negligent in failing to understand the document due to the language barrier and the salesperson's misrepresentation, they might successfully invoke non est factum.

• Example 3: Cognitive Impairment and Exploitation

  A person with a diagnosed mild cognitive impairment is approached by an acquaintance who asks them to sign a document, claiming it's a petition to support a local charity. The person, wanting to help, signs the document. It is later revealed that the document was a promissory note for a significant loan, which the acquaintance intended to default on. Given the person's cognitive impairment and the deceptive nature of the acquaintance's representation, the person could argue non est factum, as they were fundamentally mistaken about the document's nature and their mistake was not due to their own carelessness but rather their vulnerability and the other party's exploitation.