 The norm required to reach the above conclusion is this: Whenever one can somehow prove that the production of a particular good or service has a positive effect on someone else but would not be produced at all or would not be produced in a definite quantity or quality unless certain people participated in its financing, then the use of aggressive violence against these persons is allowed, either directly or indirectly with the help of the state, and these persons may be forced to share in the necessary financial burden. (Hoppe 1989: 31)