That lovable Saint Therese of Lisieux…says, for example, ‘I am assailed by the worst temptation of atheism’. Her mind is beset by every possible argument against the faith; the sense of believing seems to have vanished; she feels that it is now ‘in sinners’ shoes.’ In other words, in what is apparently a flawlessly interlocking world someone here suddenly catches a glimpse of the abyss lurking–even for her–under the firm structure of supporting conventions. In a situation like this, what is in question is not the sort of thing that one perhaps quarrels about otherwise–the dogma of the Assumption, the proper use of confession–all this becomes absolutely secondary. What is at stake is the whole structure; it is a question of all or nothing. That is the only remaining alternative; nowhere does there seem anything to cling in this sudden fall. Wherever one looks, only the bottomless abyss of nothingness can be seen.
Joseph Ratzinger, Introduction to Christianity, 42-43.