Final answer:
Past court decisions under civil law provide precedents used in later interpretations of the law, following the principle of Common Law and particularly the concept of stare decisis, meaning to stand by decisions made in the past. These precedents ensure the consistency and stability of the legal system but also allow for flexibility and change when justified.
Step-by-step explanation:
Under civil law, the concept that past court decisions act as precedents for interpreting the law is rooted in what is known as Common Law. Common Law, also referred to as case law or precedent, is developed by judges through decisions in courts that set examples for future cases, rather than through statutes from legislative processes or executive regulations.
The principle of stare decisis also allows for judicial flexibility. While precedent guides court decisions, it does not completely eliminate the possibility for new precedents or rulings to be made, especially in light of changing times and circumstances, or changes in court composition, as evidenced by landmark cases such as Plessy v. Ferguson and Brown v. Board of Education.