A statement, together with its qualifications, that postulates a constraint on the conceivable observations and that is not contradicted by observations or counter examples . E.g., the conservation law in physics (seethermodynamics ), and the law of requisite variety in cybernetics basically exclude what turns out to be empirically absent. Inasmuch as they exclude something, laws are construct ions, not to be confused with observable facts, and are often self-referential (seegoedel's theorem , self-reference , rule ). (Krippendorff )
