Bivalence is a principle in logic that states every proposition must be either true or false, with no middle ground. This means that for any statement, such as "The sky is blue," it can only be classified as true or false, not both or neither. Bivalence is a foundational concept in classical logic and helps in evaluating the truth of statements. This principle is often contrasted with other logical systems, such as fuzzy logic, where propositions can have varying degrees of truth. Bivalence is essential for traditional reasoning and is used in various fields, including mathematics, philosophy, and computer science, to ensure clarity and consistency in arguments.