Was the Encyclopédie a reference work or machine de guerre?
Setting up categories and policing them is therefore a serious business. A philosopher who attempted to redraw the boundaries of the world of knowledge would be tampering with the taboo. Even if he steered clear of sacred subjects, he could not avoid danger; for knowledge is inherently ambiguous. Like reptiles and rats, it can slip from one category to another. It has bite. Thus Diderot and d'Alembert took enormous risks when they undid the old order of knowledge and drew new lines between the known and the unknown.