Many great Philosophers during the 18^th century in France, criticized about the political tyranny, social inequality and economic exploitation in France and also insisted for reforms. Montesquieu, Voltaire, J.J. Rousseau, and Diderot were the important philosophers of France who lived much before the outbreak of the French Revolution. France was prepared mentally and morally for a revolt against the old regime because of the writings and speeches of these brilliant thinkers of that age. They strongly criticized the Church and social inequality and provided the intellectual justification for the revolution.

Montesquieu advocated the ‘Theory of Separation of Powers’ as per which, Legislative, Executive and Judiciary should function independently to safeguard the liberty of the people. Voltaire asked people to apply ‘Reason’ in every field. Rousseau gave the watchword of the revolution ‘Liberty, Equality, and Fraternity’. Diderot condemned the privileged classes.