Metalogic

Metalogic is the study of the metatheory of logic. While logic is the study of the manner in which logical systems can be used to construct valid and sound arguments, metalogic studies the properties of the logical systems themselves. While logic concerns itself with the truths that may be derived using a logical system, metalogic concerns itself with the truths which may be derived about the languages, and systems that are used to express truths.