What defines "self-defense" under criminal law?

Self-defense in criminal law is fundamentally defined by the use of necessary force to protect oneself from imminent harm or unlawful aggression. This principle allows individuals to take reasonable steps to defend their own physical safety when they perceive a credible threat. The force applied must be proportionate to the threat faced and used only when genuinely necessary to avert the danger.

For instance, if someone is being physically attacked, they are legally justified in using appropriate force to protect themselves from further injury. The key aspect is that self-defense must align closely with the concept of necessity; it should be a response to a real and immediate threat rather than a preemptive or retaliatory action.

In contrast, responses like an attack initiated by the defender or retaliatory acts do not meet the requirements of self-defense, as they do not align with the principles of responding to immediate threats. Additionally, while notification or seeking assistance might be prudent in some situations, it is not a requirement to establish a self-defense claim. Therefore, the option that accurately captures the essence of self-defense is the use of necessary force to protect oneself.