Part I

The jury is still out as to the exact relationship between the philosophes and the Revolution, but it's an oversimplification to say that Enlightenment thinkers directly caused it, and it's an even greater stretch to blame them for the Terror.

For one thing, we can't lump the philosphes together into one group, even just the French ones, which makes it hard to blame them directly for anything. Secondly, most of the philosophes were not particularly radical, but educated elites writing for other educated elites. They were interested in rational political reform, not revolution. Finally, historians have increasingly questioned how influential the philosophes were, or even whether there was such a thing as "the Enlightenment" with a capital E in the first place.

Philosophes! Which Philosophes?

It's important to remember that the Enlightenment was not a unified intellectual movement. This makes it difficult to say that "the philosophes" could be directly responsible for anything, since they weren't a coherent group. Earlier historians like Peter Gay and Jurgen Habermas tended to lump the philosophes together as intellectual crusaders for reason, secularism, economic and political liberty, but in reality they were quite heterogeneous. Socially, for example, quite a few were nobles and clergymen, like Montesquieu, Helvetius, and many of the contributors to Diderot's L'Encyclopédie. Most philosophes opposed the Catholic Church axiomatically, but they took different stances on religion. German philosophes like Leibniz remained interested in theology, while Voltaire loved to poke fun at religion but denounced atheism as a path to social anarchy, while the Baron d'Holbach advocated radical materialism and atheism. It is now common to see the Enlightenment as a number of different intellectual flashpoints, rather than a coherent event. Scholars increasingly differentiate between multiple national and religious enlightenments: a Catholic Enlightenment and a Protestant one, German, French, British, and Spanish enlightenments, including Enlightenment thought bounded by their American empires, and indigenous enlightenments, with historians like Laurent Dubois and James Sweet reminding us that enslaved Africans had their intellectual lives and were able to participate in the cross-Atlantic exchange of ideas too. All of this is to say that being a philosophe, by which I mean someone engaged in writing and thinking deeply about Enlightenment texts, implies no commonality of thought, and so it's impossible to outright claim that the philosophes or the Encyclopedists can share the blame for anything.

Revolutionary Fathers and Conspiracy Plotters

With that disclaimer out of the way, could we feasibly pin the intellectual origins of the French Revolution to a smaller group of French philosophes like Voltaire, Diderot, Rousseau for the French Revolution? The French Revolutionaries themselves certainly thought so, as did many of their enemies over the next century. The Revolutionaries interred Voltaire and Rousseau in the Pantheon as the great forebears of the nation, and other philosophes were celebrated officially through festivals and informally in books and commodities like playing cards which replaced kings with thinkers (much more egalitarian). A reading primer published in 1792 taught students about the Revolution's enlightened heritage by having them read things like this:

Q: Who are the men who by their writings prepared the revolution?

A: Helvétius, Mably, J.J. Rousseau, Voltaire, and Franklin.

Q: What do you call these great men?

A: Philosophers.

Q: What does that word mean?

A: Sage, friend of humanity.

We can see that the Revolutionaries portrayed the philosophes as their founding fathers, and emphasized their dedication to individualism, equality, religious toleration, political and economic freedom, and in general their desire to break down societal barriers. Counter-revolutionaries also portrayed the philosophes as proto-Revolutionaries, although in a more sinister way, as scheming villains enmeshed in a Europe-wide conspiracy to overthrow crown and altar.

Liberal historians in the 19th-century like Alexis de Tocqueville took a less conspiratorial view, but they still emphasized how revolutionary ideals had trickled down from the great thinkers:

"Never before had the entire political education of a great nation been the work of its men of letters, and it was this peculiarity that perhaps did most to give the French Revolution its exceptional character and the régime that followed it the form we are familiar with."