A man is presumed to be simple [minded] who makes a mistake in his own name.

Explanation

(English-origin maxim.) A man who misstates or misspells his own name raises a presumption of incapacity or fraud — cite this to challenge the authenticity of a document signed under a garbled version of the signer's name.

Where this applies

• A man signs a deed as "Robert J. Smythe" when his legal name is "Robert J. Smith"; the court raises a presumption of incapacity or fraud because a person who misstates his own name invites suspicion.
• A witness at trial gives his name incorrectly under oath; opposing counsel invokes this maxim to suggest the witness is either confused or deliberately deceptive.
• A party to a contract spells his own surname differently on three separate documents, and the court questions his competence to execute the agreement.