“The problem of pluralism that liberals face is a problem for all political moralities that are committed to some short list of values as basic. Given that commitment, the question to be answered is why those particular values, whatever they may be, are regarded as basic. Either there is or there is not an answer to the question. If there is not, then the fundamental commitments of that political morality are arbitrary. If there is an answer, then it must appeal to some even more basic value or principle or decision procedure that justifies regarding the values as basic. This answer, however, would be inconsistent with pluralism because whatever it is that the required justification is based on, it would have to be regarded as having overriding value. Because pluralism is the denial of there being any overriding value, no political morality that is committed to a short list of basic values could be pluralistic.
Liberals cannot consistently appeal to more basic overriding values and simultaneously deny that any value is overriding, as their commitment to pluralism requires them to do. Given that liberals are committed to regarding some values as basic, their commitment is either arbitrary, because it lacks justification, or it is inconsistent with their commitment to pluralism.
One of the strengths of pluralism is that it avoids this problem. It is not committed to any values as basic, and so it does not need an overriding value to justify that commitment. Pluralists can and do recognize a very long list of values that are likely to be important; they recognize that they will conflict with one another and that these conflicts must be resolved. But pluralists think that reason will dictate different resolutions in different contexts. They will not commit themselves, as liberals do, to the indefensible a priori policy of always resolving these conflicts in favor of some particular basic values. That is why if liberals were to take their commitment to pluralism seriously, they would have to eschew their other commitments, and thus cease to be liberals.”
– John Kekes, Against Liberalism –
– Lucas G. Westman