Fanaticism is a belief or behavior involving uncritical :wikt:zeal|zeal or with an obsessive enthusiasm. Philosopher George Santayana defines fanaticism as "redoubling your effort when you have forgotten your aim". The fanatic displays very strict standards and little tolerance for contrary ideas or opinions. Tõnu Lehtsaar has defined the term fanaticism as the pursuit or defence of something in an extreme and passionate way that goes beyond normality. Religious fanaticism is defined by blind faith, the persecution of dissents and the absence of reality. In his book Crazy Talk, Stupid Talk, Neil Postmanstates that "the key to all fanatical beliefs is that they are self-confirming.... fanatical not because they are 'false', but because they are expressed in such a way that they can never be shown to be false." The behavior of a fan with overwhelming enthusiasm for a given subject is differentiated from the behavior of a fanatic by the fanatic's violation of prevailing social norms. Though the fan's behavior may be judged as odd or eccentric, it does not violate such norms. A fanatic differs from a crank, in that a crank is defined as a person who holds a position or opinion which is so far from the norm as to appear ludicrous and/or probably wrong, such as a belief in a Flat Earth. In contrast, the subject of the fanatic's obsession may be "normal", such as an interest in religion or politics, except that the scale of the person's involvement, devotion, or obsession with the activity or cause is abnormal or disproportionate to the average.
Types
Consumer fanaticism – the level of involvement or interest one has in the liking of a particular person, group, trend, artwork or idea
Religious fanaticism – considered by some to be the most extreme form of religious fundamentalism. Entail promoting religious views
Sports fanaticism – high levels of intensity surrounding sporting events. This is either done based on the belief that extreme fanaticism can alter games for one's favorite team, or because the person uses sports activities as an ultra-masculine "proving ground" for brawls, as in the case of football hooliganism.
