Jean-Jacques Rousseau, the tormented genius whose ideas helped inspire the French Revolution, loved liberty above all else. Yet Rousseau’s work has justified some of the worst tyrants in history from Napoleon to Hitler and Stalin. So argues Isaiah Berlin, the 20th-century philosopher and historian of ideas in his 1952 lecture, Freedom and its Betrayal: Jean-Jacques Rousseau (weblink, iTunes), now available on the web as part of the Isaiah Berlin Centenary (iTunes, feed ).
Rousseau was, in Berlin’s words, “one of the most sinister and most formidable enemies of liberty in the whole history of modern thought.” So how can this proponent of freedom also be an enemy of liberty? The heart of the paradox, according to Berlin, is Rousseau’s belief that “nature is harmony,” a belief in the essential harmony of the universe that was common among Enlightenment philosophers.
There is a short step from this belief in harmony to the belief that “what I truly want cannot collide with what somebody else truly wants.” In other words, disagreement between two truly enlightened rational people is impossible. Therefore it follows that if I am rational and enlightened, and you disagree with me, you are simply irrational. Furthermore I am justified in forcing you to do what you truly desire (even if you are not consciously aware of your true desire.)
This then is the “lunatic” reasoning that turns freedom into its opposite. Berlin would later develop his ideas about liberty more fully in his famous 1958 essay “Two Concepts of Liberty,” available for free download here.