I think I'll stir up the Bible People...

Philosopher Friedrich Nietzche advised us to "philosophize with a hammer", to "test idols to see if they ring true". The Buddha taught that "logic is the great instrument for knowledge of the truth" , and to "Believe nothing, no matter where you read it, or who said it, unless it agrees with reason and common sense." 

So let's jump right in with the most controversial subject there is: Religion. History is driven by the "Two G's" - Gods and Greed - and the former are conduits for the latter. 

Religions are social institutions designed to control people. Notice that they all preach submission and obedience. They all promise rewards in another life, not this one. They all use the powerful indoctrination technique of repetition. They all stress faith over facts.

Religions are, at the "Leadership Level", a path to power, prestige, and wealth. If you can make others believe that you ARE a god - Emperor Hirohito, Xerxes, Haile Selassie, etc. - you have ultimate control over them and an almost unlimited ability to exact tribute. Nearly as effective is representing a god as a priest, prophet, imam, shaman, Grand Mufti, whatever. Knowing what the gods want others to do gives you enormous importance as well as the ability to collect offerings. 

So what do the followers get out of this? At the "Believer Level", religions are a reaction to stress. In a fearsome, uncertain world, there is comfort in believing that an all-powerful parenting figure can explain the unknown, love and protect you and even make you live forever. The appeal is certainly understandable. Religions also satisfy our strong innate needs to belong and to obey - we are pack animals, like all primates.

Extreme religiosity is a character disorder that crosses the line into psychosis. Such people feel compelled to not only suppress any dissonant thoughts, but also to attack anything that threatens their beliefs, because their mental health is so invested in being "right". 

The good news is that religions can perform a valuable "law enforcement" service. People tend to behave better if they think a supernatural being is watching everything they do. It works with kids and Santa Claus, right? The cops can't be everywhere, all the time. But gods and Santa can.

The bad news is that if people are trained to disregard facts in the spiritual area of their lives, they tend to disregard facts in other areas as well.

The really bad news is that religions can empower people to do horrific things, by giving them the authority of a god, the legitimacy of a group, the magnified intensity of a mob, and absolution from guilt.

These two gentlemen said it better than I can:

"If I were to suggest that between the Earth and Mars there is a china teapot revolving about the sun in an elliptical orbit, nobody would be able to disprove my assertion provided I were careful to add that the teapot is too small to be revealed even by our most powerful telescopes. But if I were to go on to say that, since my assertion cannot be disproved, it is an intolerable presumption on the part of human reason to doubt it, I should rightly be thought to be talking nonsense. If, however, the existence of such a teapot were affirmed in ancient books, taught as the sacred truth every Sunday, and instilled into the minds of children at school, hesitation to believe in its existence would become a mark of eccentricity and entitle the doubter to the attentions of the psychiatrist in an enlightened age or of the Inquisitor in an earlier time."   Bertrand Russell

"The reason organized religion merits outright hostility is that, unlike belief in Russell's teapot, religion is powerful, influential, tax-exempt and systematically passed on to children too young to defend themselves. Children are not compelled to spend their formative years memorizing loony books about teapots. Government-subsidized schools don't exclude children whose parents prefer the wrong shape of teapot. Teapot-believers don't stone teapot-unbelievers, teapot-apostates, teapot-heretics and teapot-blasphemers to death. Mothers don't warn their sons off marrying teapot-shiksas whose parents believe in three teapots rather than one. People who put the milk in first don't kneecap those who put the tea in first."    Richard Dawkins