If I go downstairs to investigate a noise at night, with a gun in my hand, and find myself face to face with a burglar who has a gun in his hand, there is danger of an outcome that neither of us desires. Even if he prefers just to leave quietly, and I wish him to, there is danger that he may think I want to shoot, and shoot first. Worse, there is danger that he may think that I think he wants to shoot. Or he may think that I think he thinks I want to shoot. And so on. “Self-defense” is ambiguous, when one is only trying to preclude being shot in self-defense.

DEFINE: Illustrates why 'self-defense' is ambiguous in reciprocal-fear situations where either party might preemptively shoot. Builds on: "Nuclear strikes impose uncertain risk beyond direct destruction."

Thomas C. Schelling, The Strategy of Conflict, loc. 461