Abstract
The attack of September 11 verified M Hardt’s and T Negri’s main thesis and by breaking with the politics of nation-state, Empire materializes under our eyes. At the same time however, event leads us to question definitions proposed in their book. It seems that we attend the end of the « small crises» which characterized Empire. And that the current visibility is how a protest against the definition of its essence as « abstract machine ». But the most serious problem is in its «ontological » foundation: the Multitudes. If they are they who support and determine the state of the Empire, are they forced to keep pace with this last one, including when the stability seems shaken ? Which is then the line of possible flight for the Multitudes ?