What is the purpose of necessity as a legal defense?

The purpose of necessity as a legal defense is to avoid a greater evil. This legal principle allows individuals to justify their actions in situations where they are faced with an imminent threat or danger that poses a more significant harm. When a defendant claims necessity, they are asserting that their actions, though typically illegal, were taken to prevent a more serious consequence, such as injury to themselves or others.

For instance, if a person breaks into a cabin during a snowstorm to escape the cold and prevent hypothermia, they could argue that their action was necessary to avoid a greater harm. The focus here is on the reasoning that the harm caused by the illegal act is outweighed by the harm that it prevents, which reflects the core essence of the necessity defense.

The other options do not fully capture the essence of the necessity defense. While ensuring justice, deterrence, and rehabilitation are important aspects of the legal system, necessity specifically targets situations where immediate and dire choices are made to avert more significant threats or harms.