The effect of the Enlightenment on the French Revolution has created a debate which will not be resolved soon. However, in general, it can be said that there is no casual relationship between the philosophies of the Enlightenment and the outbreak of the French Revolution. Few philosophies, if any, advocated revolution for one reason which is very clear. The violent overthrow of the existing order of things was not advocated because violence is contrary to human reason. However, because the philosophies of the enlightenment attacked the established order together with authority of any kind, their ideas helped to produce what can only be called a revolutionary mentality.
The philosophies advocated the use of reason in all human affairs. They knew that reason, together with its sister, criticism, could affect change. Change in morals, a change in human knowledge, and a change in human happiness. In rhetoric and institution, the French Revolution was a liberal revolution in which the liberty of the individual was proclaimed and private property was respected. The cornerstone of the Enlightenment proved to be the key that would unlock the door of the absolute monarchy. That key was ideology.
Ideology is, in a way, the secular equivalent of theology. It directs the believer's attention to a perfected future when present woes will have dissipated and social harmony will reign. The future, therefore, holds the promise for the ideologue that heaven holds fo the devout, religious-minded individual. The introduction of ideology into the modern world was one major effect of the new secular spirit of the enlightenment. Once society was deemed to be man-made, then it could be changed. Ideology was the prescription for that change, and the force of it was felt throughout the modern era.
However the philosophers of the Enlightenment and their ideas did not, in themselves, incite the revolution. Indeed when we examine many of the philosophers of the time we see a mixed bag of people and ideas.