On the characterization of liberalism by Samet and Schmeidler

In the model of group identification, Samet and Schmeidler (J Econ Theory 110:213–233, 2003) provide two axiomatic characterizations of the“liberal” decision rule (a person is socially qualified as a member of a collective if and only if he qualifies himself). They impose standard monotonicity, non-degeneracy, and independence axioms, together with either exclusive self-determination (opinions by disqualified persons about qualified persons should not matter) or affirmative self-determination (social decision on who are qualified should coincide with social decision on who should be the qualifiers). Dropping monotonicity (and also non-degeneracy in a result) and considering a more general domain to allow neutral opinions, we characterize a larger family of “self-dependent” rules that share the important feature of liberalism that qualification of i depends only on i’s own opinion about himself or herself. Samet and Schmeidler’s results can be obtained with a weaker set of axioms and with a more general domain condition.