The God Delusion

The God Delusion is a book by Richard Dawkins published in 2006.

Arguments for God's existence
Dawkins lists the following arguments:


 * Thomas Aquinas' five proofs:
 * The unmoved mover
 * The uncaused cause
 * The cosmological argument
 * The argument from degree
 * The teleological argument
 * The ontological argument
 * The argument from personal experience
 * The argument from scripture
 * The argument from admired religious scientists
 * Pascal's wager
 * Bayesian arguments

Why there almost certainly is no God
Dawkins begins this chapter by characterizing God as "the ultimate Boeing 747": any complex entity requires an explanation for its existence &mdash; as creationists are fond of pointing out, it would be absurd to think that a tornado could sweep through a junkyard and assemble a Boeing 747. But if any complex entity must have been designed and built by an even more complex entity, then God, who made the entire universe, must be even more complex, and we can therefore ask who created God?

Dawkins then reprises the central theme from his book, Climbing Mount Improbable and says that natural selection is the only known mechanism that can produce complexity from simplicity.

He corrects creationists' misunderstandings about evolution and demonstrates the flaws in the concept of irreducible complexity and the question, "what good is half an eye?" He criticizes irreducible complexity as a god of the gaps argument, and shows how creationists use it as an excuse to give up research instead of seeking for answers.

Dawkins then introduces two versions of the anthropic principle to explain life on earth: in the "planetary version", he argues that while it's true that Earth has many properties that make it suitable for life, the universe is vast enough that some such planets must exist solely by chance. Of course Earth is one of these, since otherwise life could not exist here; but if Earth had been unsuitable for life, life would have arisen elsewhere in the universe.

This statistical argument does not hold for the universe as a whole, since there is only one universe that we know of. Yet creationists also apply the fine tuning argument to the universe as a whole, arguing that the fundamental constants of the universe are set to precise values that make matter &mdash; stars, galaxies, humans &mdash; possible. Dawkins counters by suggesting that the fundamental constants of the universe may depend on each other, and are therefore not as free to vary as creationists suggest. He also suggests that there may be a multitude of universes (in which case the statistical argument applies), and that perhaps black holes create new universes with constants close to those in their parent universes. If this turns out to be the case, darwinian evolution applies, and our universe is the way it is because it comes from a lineage of universes that have evolved to produce black holes (and the existence of stars, planets, and life is a side effect of black hole production).

Finally, he recounts a conference he was invited to, in Cambridge, organized by the Templeton Foundation, and his disappointment in the quality of theologians' replies to his arguments.

The roots of religion
In this chapter, Dawkins explores possible natural scenarios for how religion could have arisen naturally, without the existence of any gods. He begins by noting that to an evolutionary biologist, religious behavior is expensive in terms of time and effort: why pray five times a day, or build cathedrals? Surely such behavior requires an explanation.

Religion might give consolation and comfort, and reduce stress the way a placebo does. However, religion is also a significant cause of stress (e.g., Catholic guilt). On balance, the placebo hypothesis is not a significant explanation.

Dawkins considers group selection: an army of martyrs who believe that they will be rewarded with paradise if they die in combat has an advantage in battle over more peaceful neighboring tribes. Dawkins rejects this explanation because intra-tribal selection is stronger than inter-tribal selection: if an army of martyrs contains one coward who holds back, the army is almost as likely to win the battle, but the coward is significantly more likely to survive and have children.

Religion may not be beneficial in itself, but may be a byproduct of something else, which is beneficial. In particular, children who believe their elders when they say things like "don't go swimming in the river; there are alligators there who will eat you" are more likely to survive than children who insist on finding out for themselves. Such unquestioning belief has drawbacks, like occasionally believing something that isn't true, but these drawbacks are minor compared to the advantage of not dying young.

Humans may be psychologically primed for religion: experiments have shown that children naturally have a dualistic theory of mind. That is, they believe that mind and matter are different things, as opposed to monism, the notion that mind arises from matter. Since many religions teach that mind (or soul) and body are separate, people are predisposed to believe it.

Other psychological theories suggest that children are naturally predisposed for teleology: they believe that "clouds are for raining", or that sharp rocks exist so that animals can scratch their backs. This predisposes them to believe in creationism.

There is an evolutionary advantage to this: what Daniel Dennett calls the "intentional stance"&mdash;that a phenomenon is caused by an "agent" which "wants" to achieve some goal&mdash;is a good way of quickly reacting to a situation. One could work out from its anatomy that a tiger is dangerous, but it is much quicker to assume that the tiger is an agent whose goal is to eat. The intentional stance is also useful in social settings, e.g., "He's looking away so that I won't notice that he wants to have sex with my wife". A predisposition toward holding the intentional stance is a useful survival mechanism, but also predisposes people toward believing in creationism.

Religion may also be a side effect of love: when one falls in love, one tends to believe that the object of one's affection is superior to everyone else, even when this is objectively not the case. Such irrational beliefs have obvious advantages for the stability of the relationship. Religious beliefs often cause people to feel and act the same way as people in love, so there may be a relationship between love and religion.

Dawkins then explores the idea of religion as a product of evolution among memes. Ideas like immortality are appealing, and therefore more likely to be passed on. Ideas like "God grants immortality", "faith is a virtue", and "doubters must be shunned" can work in concert to protect each other. Scientology and Mormonism are presented as examples of "intelligently designed" religions.

Finally, Dawkins talks about cargo cults, religions that have arisen in modern times. We have seen them arise from false beliefs, and persist in the face of evidence. Is it not then possible that Christianity arose in a similar way?