Why does philosophy fight over words? The realities of the class struggle are ‘represented’ by ‘ideas’ which are ‘represented’ by words. In scientific and philosophical reasoning, the words (concepts, categories) are ‘instruments’ of knowledge. But in political, ideological and philosophical struggle, the words are also weapons, explosives or tranquilizers and poisons. Occasionally, the whole class struggle may be summed up in the struggle for one word against another word. Certain words struggle amongst themselves as enemies. Other words are the site of an ambiguity: the stake in a decisive but undecided battle.