"Marx, although a man of broad knowledge, had one blind spot: he was ignorant of the true character of economics. He did not realize that economics can only be understood in close relationship to the other humanities (and certain sciences), and therefore should not be studied in vacuo. Ironically, this very weakness was largely instrumental in making Marxism successful. Marxist economics—yet another instance of a false but clear idea—can be explained to the merest child in a matter of minutes. (Conversely, to explain the workings of the free market economy to an adult would take weeks of hard work.) Because it was easily grasped, Marxism flooded the world within a few decades, as had other simplistic ideologies and religions, such as Islam and the Enlightenment; this same sort of simplicity gave rise to the French Revolution and national socialism. Christianity, on the other hand, took three centuries to triumph."