Morality As a Limit
Pacifism is the moral principle that the use of force is wrong for any reason. This applies to both the initiation of force, as well as defensive or retaliatory force. If your life is being threatened, pacifism holds that you should not defend yourself. If someone has stolen from you, pacifism holds that you should not retrieve your property. If someone has murdered other people, pacifism holds that nothing should be done about it. Pacifism is the moral principle that attempts to permanently disarm its practitioners, leaving them helpless and at the mercy of any thug.
Some people accept pacifism due to a faulty inductive process. They notice that force can be used for evil, and generalize it believing that force is only used for evil. Others accept pacifism as a moral commandment or duty. There is no rational reason to accept pacifism, and its consequences are deadly. This ethical premise is destructive to one's life and values. It makes morality oppose self-interest, and requires the choice of either being good, or being alive.
Pacifism requires one to withhold the use of force. It is thought that if practiced by everyone, the world would be a better place, making life easier to live. This is mistaken, though. A single thug could destroy any society based on pacifism. Since nobody could respond with equal force, even in self-defense or the defense of their loved ones, the thug would be constantly rewarded for his acts. He could rob, steal, or murder, and nobody could stop him. It would encourage others to act this way as well, since nobody would be willing to stop them. But one cannot live under such circumstances. One's life would be at the mercy of the worst people alive.
Pacifists are able to survive in as far as either they abandon this faulty principle, or others dismiss it. Without the use of retaliatory force, they could not survive against the threat of other people. A lone pacifist in a society willing to enact justice can survive at the expense of his fellow citizens. It is to them that his survival is maintained. It is his ethical system that makes him dependent on the good will of others.