Defined in psychological terms, a fanatic is a man who consciously overcompensates a secret doubt.

Summary

This quote suggests that a fanatic is a person who, at a deeper level, has some doubt or uncertainty about their beliefs. To compensate for this inner doubt, the fanatic consciously exhibits excessive passion or devotion towards their beliefs or ideology. This suggests that their fanaticism is not entirely genuine or confident, but rather a way to mask their underlying doubts and maintain an unwavering facade. It implies that fanatics may push their beliefs so vehemently in an attempt to convince not just others, but also themselves, of their truth.