Systems theory is a theoretical response to the dangerous natural fact that humans are more able to influence than to think of everything when making decisions and acting. System theory and cybernetics need and support transdisciplinary and inter-disciplinary approaches. How? A dialectical system of seven principles provides the first answer. We suggest, as its second step, the law of requisite holism. Cooperation of several systems theories may be a good case. Several laws including the notion »requisite« may jointly / in synergy lead to the third step. Information needs may define limits. This synergy/system/network may help us find the common sense of the uncommon sense called systems thinking/theory: (requisite) holism.The original publ...