The old rule known as falsa demonstratio non nocet is actually a reflection of Article 19 of the Turkish Code of Obligations. It means that a false statement will not be taken into consideration as long as the real intent of the parties can be interprited. In other words, false statements that do not reflect the real will of the parties should not be taken into account during interpretation. The rule is important not only in succession law but also in contract law. This is particularly true during interpretations of contracts and declarations of intent because it enables one to draw the line between real intent and fictive intent. Objective interpretation theories that are based on fictive intent do not apply as long as real intent can be determined. Thus, it is important to clarify the function of rules in contract law.