A/50/476 English Page 18 countries of migrant workers of African origin. Physical frontiers have psychological consequences in the sense that they not only represent political and legal limits, but are also considered to contain within a precise area the feeling of belonging to a particular group. 36. This may help to explain the fact that, although the notion of race has been called into question by science, 12/ it still retains such significance in people’s minds that it permits them to define physically and psychologically the separation between "us" and "them", despite the illusory nature of that separation. 37. According to Jean-François Kahn, "race is reassuring because it seems to give rationality to distinctions, and because it affords protection by isolating the collective identity which it denotes. It makes the strangeness of others the justification, and indeed the condition, for the affirmation of one’s own identity." 13/ 38. There can be no denying that, while all the pseudo-scientific racist theories have collapsed, attitudes and behaviour patterns persist, as if racism could exist in the absence of any justification derived from a "science" of race. Proclaiming that "race" does not exist has not succeeded in putting an end to discussion of possible objective distinctions, especially since the deadly logic of racism is founded upon the notion that it "has to do with natural physiological reality - the white or black colour of the skin - the appearance of which cannot be changed by persuasion or by any government intervention; the only solution in such cases is to exterminate the bearers of the ignominious mark." 14/ It is the very non-existence of race that gives renewed forms of racism their remarkable flexibility. 15/ 39. That flexibility is shown by the current shift of racist arguments towards cultural differences rather than biology. It is not so much a matter of the recognition of the individual’s membership of a group or community or the recognition of cultural particularities; the problem lies in a hierarchical classification of such membership and, consequently, of the cultures themselves, and in the negation of otherness in the interest of "making cultural differences absolute", 16/ as if some impermeable barrier prevented any exchange or interaction between human communities, dooming them for eternity to some imagined homogeneity and purity. 40. This is the type of mythical ideology which has been adopted by the adherents of contemporary racism and racial discrimination, the supporters of ethnic cleansing and preference for nationals, who are active on every continent; in one place they persecute foreigners or refugees, in another their victims may be Bosnians, Tutsi or Hutu, or American Indians. It is these attempts to pervert cultural relativism and to negate ethnic and racial plurality that the opponents of racism and racial discrimination have to confront. Racism proves to be a persistent and hardy phenomenon, with recurrent manifestations and intense attacks, like paludism or malaria which is more deadly than any other disease. Man can achieve his full dignity only by waging relentlessly the one true battle: the battle to reduce and eradicate racism. /...