A more thorough explanation:

Definition: Bad-Man Theory is a legal doctrine that suggests that the view of the law held by a bad person is the best way to understand what the law actually is. This is because a bad person will carefully calculate what the rules allow and operate up to the limits of those rules.

Oliver Wendell Holmes first introduced this theory in his essay "The Path of the Law" in 1897. According to Holmes, a society's legal system is defined by predicting how the law will affect a person, rather than considering the ethics or morals underlying the law. The prediction is best made by viewing the law as a "bad man" who is unconcerned with morals.

For example, imagine a person who wants to steal a car. They will carefully consider the laws related to car theft and plan their actions accordingly. They will not be concerned with whether stealing a car is morally right or wrong, but rather whether they can get away with it without incurring punishment by the law.

The Bad-Man Theory suggests that by understanding the perspective of a bad person, we can better understand how the law operates in practice. This theory is often associated with Legal Realism, which emphasizes the importance of understanding how the law is actually applied in the real world.