The correct answer is: "Social contract".
The Enlightenment philoshophers such as Locke or Rosseau, developed ideas and principles which challenged and ended up tumbling the power structures of the Old Regime.
They promoted democratic principles, such as the definitions of bills of citizens' rights, universal suffrage, social contract (citizens electing political representatives to form a goverment through suffrage, in opposition to the prevailing absolut monarchies), and the division of the powers of the state in order to avoid excessive power accumulation in certain sectors, and therefore authoritarist risks.