Article 4 proscribes "slavery or servitude"; Article 5 states that "no one shall be subjected to torture or to cruel, inhuman or degrading treatment". Next to the arbitrary murder of others on the alleged grounds that they are inferior racially, doctrinally, or in some other way, slavery and torture are unquestionably the most abhorrent violations of human rights.

Yet there are few major states in the world, not even those that most loudly chant the mantras of liberty and democracy, that are guiltless of subjecting some of their enemies – and indeed some of their own citizens – to torture or at least inhuman and degrading treatment: not the US, not the UK, certainly not the People's Republic of China.

Shall we not torture the man who knows where the dirty nuclear bomb is hidden in the city centre? A utilitarian would not hesitate to waterboard him, or push the bamboo splinters up behind his nails. Some make this question a test for how serious one is about individual rights. The drafters had in mind rape of women in conquered populations, the use of prisoners for bayonet practice, the abandonment of starving prisoners to languish in their own ordure. The test case question and the question of civilised behaviour generally – for which the test is surely the same – are part of the same debate.

As to slavery: according to UN figures, there are more people enslaved today than the total carried to the Americas in three centuries of the Atlantic slave trade: 12 million. Slavery takes many guises and bears many different names now, but it is "slavery and servitude nonetheless", characterised by coercion, lack of remuneration, and lack of choice.

One of the standard objections to the UDHR is that it is a western Enlightenment invention, and that its claim to universality is spurious. Few things refute this allegation so swiftly as thoughts of torture and slavery. The mammalian nervous system, and what coercion involves, are the conclusive data. For my money these thoughts govern how we should treat all animals generally; so if cows and chickens should not be treated cruelly, still less should any human be so treated. So much for relativism.

Doubts about the UDHR's universality were voiced early, and not at first by people in colonised and developing countries, who welcomed the UDHR with open arms (it was the big powers who were suspicious of it, as threatening to interfere with the exercise of their hegemony), but rather by bien pensants in the western world itself. In 1947 the American Anthropological Association voiced concern that ideas of human rights are ethnocentric, and in their submission to Eleanor Roosevelt's committee urged that it take account of the relativity of values to culture, and the point that since an individual "realises his personality through his culture, respect for individual differences entails respect for cultural differences". The trouble with this, as just noted, is that pain and privation are not respecters of culture.

In any case, cultural bias is not always a bad thing. Those cultures that condemn genital mutilation of girls are justified in condemning the cultures that practice it, because they can make a case that members of the latter cultures would be bound to accept in other respects. Thus, if asked if they wish to be protected from harm (say, from having their homes burned and livelihoods destroyed), from pain and mutilation (say, from having a hot poker plunged into their eyes), and from imposed dangers to health (say, from poison being put into their water supplies), they would presumably answer, yes. Then the entirely objective fact that "female circumcision" and vaginal infibulation are all three of these things, together with a challenge to assumptions about the putative importance of virginity and the claim that male sexual pleasure has an importance that overrides the health and wellbeing of their wives, ought to settle the matter for any open-minded and normally intelligent person.

Again, so much for relativism. And that is an important point, because Articles 4 and 5 are an explication of Article 3's "life, liberty and security", and show that it applies without borders.

AC Grayling will continue with a daily blog on the UDHR through to the 60th anniversary itself on December 10.



The Guardian is the media partner for The Convention on Modern

Liberty, taking place on Saturday February 28 2009, which will debate these and other issues. You can buy tickets here