Liberalism can, of course, offer other solutions to the problem of
social unity. Some liberals consider that a Hobbesian modus vivendi
should be enough to provide the type of consensus required by a
pluralistic society. Others believe that a constitutional consensus on
established legal procedures fulfils that role as effectively as would a
consensus on justice. But 'political liberalism' finds those solutions
wanting and proclaims the need for a moral type of consensus in which
values and ideals play an authoritative role.