The Zero Aggression Principle (or ZAP) is a personal philosophy designed to allow individuals to self-govern their interactions with other individuals. The Principle states: No human being has the right — under any circumstances — to initiate force against another human being, nor to threaten or delegate its initiation.
The primary advocacy group of the Zero Aggression Principle is the Zero Aggression Institute (0AI).
The Zero Aggression Principle uses the term "force" to mean coercion of one individual by another. The Zero Aggression Principle differs from other personal philosophies in that it defines force as morally neutral. Force can be used morally or immorally; the distinction depends on the context in which it is used.
Initiated force is defined as immoral while force used in response to initiated force is moral.
For example, if one individual were to put a gun in the back of a second individual and demand money, this would be an immoral Initiation of Force (IoF). Were the second individual to draw a sidearm and shoot the first, this would be a moral use of Force In Response (FIR).
The Zero Aggression Principle makes no exceptions. It is equally immoral for a President, King, or Emperor to initiate force as it is for a citizen, subject, or serf.
For purposes of self-governance of individual interactions, the Zero Aggression Principle essentially means that any individual may engage in any activity they like provided that it not initiate force against another individual.
Many individuals find that this is an inadequate philosophy, often for spiritual or religious reasons. The Zero Aggression Principle isn't designed as a replacement for other personal philosophies, but rather a simple super-philosophy designed to allow individuals of radically different beliefs to interact peacefully. It is not a violation of the Principle to also believe in a religious faith. However, it is a violation to initiate force against another individual based on religious or spiritual beliefs.
It is impossible to codify the Zero Aggression Principle into law — in fact, it would be a violation of the Principle to do so. For a government to enforce the Principle would require coercion on the part of government. As stated above, state-sanctioned coercion is not excepted from the Principle.