The noteworthy philosophes of the Enlightenment rarely attacked outright the social hierarchy that they were part of. The abuses of the church, the ignorance of the nobility, even the injustices of kings might be fair game for criticism, but none of the better-known philosophes called for the equivalent of a political revolution. Only Rousseau was bold enough to advocate a republican form of government as a viable alternative to monarchy, and his political ideas were far less well-known during his lifetime than were his ruminations on education, nature, and morality. Even Kant’s essay celebrated what he described as the “public use of reason,” namely intellectuals exchanging ideas, while defending the authoritarian power of the (Prussian, in his case) king to demand that his subjects “obey!”
The problem was that even though most of the major figures of the Enlightenment were themselves social elites, their thought was ultimately disruptive to the Christian society of orders. Almost all of the philosophes claimed that the legitimacy of a monarch was based on their rule coinciding with the prosperity of the nation and the absence of cruelty and injustice in the laws of the land. The implication was that people have the right to judge the monarch in term of his or her competence and rationality. Likewise, one major political and social structure that philosophes did attack was the fact that nobles enjoyed vast legal privileges but had generally done nothing to deserve those privileges besides being born a member of a noble family. In contrast, philosophes were quick to point out that many members of the middle classes were far more intelligent and competent than was the average nobleman.
In addition, despite the inherent difficulty of publishing against the backdrop of censorship, philosophes did much to see that organized religion itself was undermined. The one stance all of the major Enlightenment thinkers agreed on regarding religion was that “revealed” religion - religion whose authority was based on miracles - was nonsense. According to the philosophes, the history of miracles could be disproved, and contemporary miracles were usually experienced by lunatics, women, and the poor (and were thus automatically suspect from their elite, male perspective). Miracles, by their very nature, purported to violate natural law, and according to the very core principles of Enlightenment thought, that simply was not possible.
Thus, the Enlightenment did more to disrupt the social and political order by the late eighteenth century than most of its members ever intended. The most obvious and spectacular expression of that disruption took place in a pair of political revolutions: first in the American colonies of Great Britain in the 1770s, then in France starting in the 1780s. In both of those revolutions, ideas that had remained in the abstract during the Enlightenment were made manifest in the form of new constitutions, laws, and principles of government, and in both cases, one of the byproducts was violent upheaval.
Image Citations (Wikimedia Commons):
Salon of Mme. Geoffrin - Public Domain
Encyclopedia Illustration - Public Domain