Define the Parole Evidence Rule. What does the Solution Parole evidence rule governs the contract cases in court. It prevents the parties involved in a written contract from presenting any extrinsic evidence that is not mentioned in the final written agreement. As per the rule the parties to a contract needs to mention each agreement in the contract itself, any verbal agreements made before or during the final contract would not change the terms of the original contract. As per the “four corners” directive, a court should accept only those contract terms that are mentioned inside the “four corners” of the paper in which the contract is printed upon. Evidences or terms that are not included in the paper would not be considered valid. However, in the following situations outside evidence would be admitted by the court: External proof in order to show that the contract is ambiguous or invalid Evidence to support that a term was mistakenly transcribed Evidence to show that the consideration was never paid by other party To identify other party who have changed their names due to some legal means like marriage or corporate merger..