From Francois Furet’s Interpreting the French Revolution, quoted by Kevin Williamson in We’re All Jacobins Now in National Review:

Here I am using the term ideology to designate the two sets of beliefs that, to my mind, constitute the very bedrock of revolutionary consciousness. The first is that all personal problems and all moral or intellectual matters have become political; that there is no human misfortune not amenable to political solution. The second is that, since everything can be known and changed, there is a perfect fit between action, knowledge, and morality. That is why the revolutionary militants identified their private lives with their public ones and with the defense of their ideas. It was a formidable logic, which, in laicized form, reproduced the psychological commitment that springs from religious beliefs. When politics becomes the realm of truth and falsehood, of good and evil, and when it is politics that separates the good from the wicked, we find ourselves in a historical universe whose dynamic is entirely new. As Marx realized in his early writings, the Revolution was the very incarnation of the illusion of politics: It transformed mere experience into conscious acts. It inaugurated a world that attributes every social change to known, classified, and living forces; like mythical thought, it peoples the objective universe with subjective volitions, that is, as the case may be, with responsible leaders or scapegoats. In such a world, human action no longer encounters obstacles or limits, only adversaries, preferably traitors. The recurrence of that notion is a telling feature of the moral universe in which the revolutionary explosion took place.