Powerless

The facts of life do not penetrate to the sphere in which our beliefs are cherished; they did not engender those beliefs, and they are powerless to destroy them...


This is why you can't argue with a zealot.

The complexity of circumstances

There is probably no one, however rigid his virtue, who is not liable to find himself, by the complexity of circumstances, living at close quarters with the very vice which he himself has been most outspoken in condemning...


The irony comes with those who are not, shall we say, rigid in their own virtue at all, yet remain sanctimonious in their condemnation of some alleged vice or another. Because Proust's comment here relates to a character--M. Vinteuil--whose daughter is widely suspected of being a lesbian (the word of course is not uttered), a certain recent vice president (ah! "vice" president!) of the U.S. comes to mind.