What does it mean to believe in the right to liberty, or in any other human right for that matter? To work properly, this language of human rights does seem to need to be based on truth, on being right, and on knowing we are right. The very term "human rights" is a strong one, epistemologically confident, ethically assured, carrying with it a promise to the hearer to cut through the noise of assertion and counter-assertion, of cultural practices and relativist values, and thereby to deliver truth.

To work its moral magic, human rights need to exude this kind of certainty, this old-fashioned clarity. To say "I have a right to" is not to suggest something, it is to state it; it is not to ask, it is to demand. Those of us who are part of the human rights community do come across a bit smug in contrast to the rest of society - we know the right answers, we have special access to the truth.

This is not ordinary politics, we say, this is morality, this is about right and wrong - and we know, even if you mere mortals don't, which is right and which is wrong, not as a matter of policy but as a statement of truth. This is not how most of politics works. Indeed it is not how the world works: uncertainty rather than certainty is, perhaps more than anything else, the key defining feature of our culture today.

Where does this leave the term "human rights"? The easy answer would be to confine it exclusively to the legal sphere, to say that human rights can only mean the values encapsulated in documentary form in international, regional and national legal agreements, as interpreted by decision-makers and, at a later remove where there has been dispute, the courts. But this is a very narrow approach that fails to capture what many people, perhaps most, mean today when they refer to "human rights". The words can be made to do more work, to reach a wider shared meaning beyond what has been reduced to legal form.

But which values should drive the language of human rights, and how can we avoid the criticism that they are purely Western and therefore entirely non-universalistic?