If the aspirant deserts the quest in sheer fatigue or outer despair, he loses his way. For the world will satisfy him only for a limited time, and then discontent with it will erupt afresh. If, however, he continues to persevere, then holy visitations will come more frequently and remain longer. He will lose nothing in reality unless and until he loses heart. For that is in the realm of secret causes, while things are in the realm of visible effects. So long as failure does not get inside a man, so long is the road to victory still open before him. The patience which is required of the aspirant is often tremendous. He will be tempted again and again to give up in despair. Although conscious of his ignorance, sensitive to his inadequacy, and recognizing his incapacity, he will not escape falling into moods of despondency. He will need the rare quality of endurance where even repeated defeats will not make him give up the struggle. He will probably pass through various phases of enthusiasm for philosophy and antipathy for it, but despite these alternations he will know in his inmost heart that he can never forsake it. Eventually, he will get the philosophic outlook which, although it sees his own human limitations and knows his own human possibilities, will refuse to despair.
-- Notebooks Category 2: Overview of Practices Involved > Chapter 3 : Uncertainties of Progress > # 200