Legal doctrines are established principles or rules that guide the interpretation and application of laws in various legal contexts. They help courts and legal professionals understand how to approach specific cases by providing a framework based on previous rulings and legal theories. These doctrines can evolve over time as new cases arise and societal values change. Examples include the doctrine of precedent, which emphasizes following past judicial decisions, and the doctrine of stare decisis, which ensures consistency in the law by obligating courts to adhere to established rulings.