The Theory of Defense is a legal doctrine used to establish the legal justification for the use of force in self-defense. It is based on the principle that one has the right to defend oneself and one's property against unlawful acts or threats of violence. The Theory of Defense is based on the idea that individuals have the right to protect themselves against physical harm or threats of physical harm. This may include using physical force, deadly force, or other measures necessary to protect oneself from harm. There are three main types of Theory of Defense: Imperfect Self-Defense, Perfect Self-Defense, and Necessity Defense. Imperfect Self-Defense is used when one believes they are in imminent danger of harm, but their belief is not objectively reasonable. Perfect Self-Defense is used when one is in actual imminent danger of harm and their belief is objectively reasonable. Necessity Defense is used when one believes they must use force to prevent a greater evil from occurring.