 The second insight, indeed, is that no-envy itself is a combination of conflicting principles (Fleurbaey and Maniquet 2011a, Fleurbaey 2008). This conflict is made apparent in models with talents and handicaps. For instance, Pazner and Schmeidler (1974) found out that there may not exist envy-free and Pareto-efficient allocations in the context of production with unequal skills (when there are high-skilled individuals who are strongly averse to labor). This results from an incompatibility between a compensation principle saying that individuals with identical preferences should have equivalent bundles (suppressing inequalities due to skills), and a reward principle saying that individuals with the same skills should not envy each other (no preferential treatment on the basis of different preferences). Both principles are a logical implication of the no-envy test. This is obvious for the latter. For the former, notice that no-envy among individuals with the same preferences means that they must have bundles on the same indifference curve. Interestingly, the compensation principle is a logical consequence of solidarity principles and is therefore perfectly compatible with them. It is very well satisfied by egalitarian-equivalent allocation rules. In contrast, it is violated by Dworkin’s hypothetical insurance which applies the no-envy test behind a veil of ignorance (see Dworkin 2000, Fleurbaey 2008, and  § 3.2).  A recent philosophical analysis of the no-envy approach has been developed in Olson (2020). The relation between envy and theories of justice is also scrutinized in the entry on  envy.