In the Estates General, each Estate got one vote even though over 95% of the French people were in the Third Estate (D2). We know that the First and Second Estates always voted together, and overrode the vote of the Third Estate. From excerpts from cahers (complaints) brought to the Estates General by the Third Estate, we learn that the Third Estate wanted all the votes to be proportionate to the number of people in each estate so they would be represented more fairly (D3).
A third cause of the French Revolution was the Enlightenment Period, which was a time when European philosophers began a movement away from tradition toward reason and individualism. Many educated people from the Third Estate knew about the Enlightenment writings, and used those ideas, along with their frustration about high taxes and underrepresentation in the Estates General, to fuel the Revolution. We know from Albert Mathiez’s The French Revolution that the Third Estate led the Revolution because they knew the most about Enlightenment ideas