Much of what people do is done in the name of God. Irishmen blow each other up in his name. Arabs blow themselves up in his name....Thus Dawkins begins an essay entitled "The Improbability of God." Now, it's obvious from the title and the opening sentences of the essay where Dawkins is going, but there is no logical connection between the vile acts purportedly committed in God's name and the existence of God. Sectarian violence of the kind seen in Ireland and the Middle East violates the tenets of Catholicism, Protestantism, Judaism, and most forms of Islam -- not to mention Hinduism, Buddhism, and other Eastern religions.
Why single out a belief in God as a cause of violence? What about the "religion of the state" or the "cult of personality" as practiced under Hitler, Stalin, Mussolini, Mao, and Saddam Hussein, among many others of their ilk?
Violence comes from humans. God -- or more precisely, religion -- is but one excuse for violence. There are many other excuses. The existence of violence neither proves nor disproves the existence of God. Dawkins's opening is a cheap rhetorical trick, designed to cater to emotion rather than reason. Not very scientific, eh Professor Dawkins?