The lesson of Eve and Adam, eh?
Dunno, my experience tells me that you can be both reasoned and happy. The idea that they are exclusive seems wrong to me.
Also, it's irritating how Voltaire uses clever equivalency of the old woman's faith with her ignorance and bigotry. He never suggests that it's her faith that gives her grounding. Well, that would not be his point. But it is another way of looking at it.
People reason all the time and are happy as clams, but it can't be psuedo-reasoning. We have to reason from reality, if we don't then we are conflicted, no? I don't know that any of us ever do, not all the time. The ignorant can be stupid yet smart, and the world has always contained educated, smart people who are plenty stupid in super clever ways.