 This principle can also be incorporated into hierarchical, inegalitarian theories. It indicates that equal output is demanded with equal input. Aristocrats, perfectionists, and meritocrats all believe that persons should be assessed according to their differing deserts, understood in the broad sense of fulfillment of some relevant criterion. Reward and punishment, benefits and burdens, should be proportional to such deserts. Since this definition leaves open who is due what, there can be great inequality when it comes to presumed fundamental (natural) rights, deserts, and worth -– this is apparent in both Plato and Aristotle.