Breakin' the Law
Natural Law
This is not things like thermodynamics and gravity. It's the law that governs the behavior of natural beings. These weren't so much specific laws as they were principles that guided judgment. For example, people need to eat. It's a natural law. Therefore, starving people may do things that a well-fed man would not. It's natural to be jealous, to seek revenge, to protect one's home. Marriage is a natural state. Property ownership is natural. There are natural leaders. These and other principles were understood by jurists to be "natural laws" as immutable as physical laws.
The one that's most widely recognized is the principle of self-defense. This is not divinely ordained; rather, it's the instinctive reaction of any living being to preserve its own life if attacked. Any court of law must take into account natural law. In reality, the only people who made explicit reference to natural law were the jurists. Real people and real courts did not. But ideas about natural law formed an important underpinning.