A more thorough explanation:

The presumption-of-identity rule is a common-law principle that applies when there is no specific statute in another state. It presumes that the common law has developed identically in other states as it has in the court's own state. This allows the court to apply its own state's law.

For example, in the case of Shorewood Packaging Corp. v. Commercial Union Ins., the court in Georgia applied the presumption-of-identity rule. The court presumed that the common law in other states had developed identically to Georgia's common law. Therefore, the court applied Georgia's law to the case.

Another example of the presumption-of-identity rule is when a court in California applies its own state's law to a case involving a contract dispute with a party in New York. The court presumes that the common law in New York has developed identically to California's common law. Therefore, the court applies California's law to the case.

The presumption-of-identity rule is important because it allows courts to apply their own state's law when there is no specific statute in another state. This helps ensure consistency in the application of the law across different states.