The Archbishop of Canterbury has used a university lecture to hit back at people who criticise religion.
Dr Williams responded to authors such as Richard Dawkins
Dr Rowan Williams said many worshippers would not recognise their religion as described by some authors.
Dr Williams said: "When believers pick up Richard Dawkins or Christopher Hitchens, we may feel as we turn the pages 'this is not it'."
The archbishop gave his lecture to more than 1,000 people at the Taliesin Arts Centre, in Swansea.
Dr Williams told the critics: "Don't distract us from the real arguments by assuming that religion is an eccentric survival strategy or irrational form of explanation."
Biologist Professor Dawkins attacks God "in all his forms" in his best-selling book The God Delusion.
Christopher Hitchens has also criticised religion in his book God is Not Great: How Religion Poisons Everything.
Dr Williams said religion could not be viewed from a scientific point of view because belief in God was unconditional.
"'I believe in the Father, the Son and the Holy Spirit, subject to further explanation', is not a creed that's prevalent in the Christian world," he said.
He added: "The believer who worships assumes absolutely that God is there and worth attending to."
Dr Williams also expressed concern that some people described themselves as Christian simply to mean non-Muslim.
He said: "I think that's rather worrying. That doesn't make for anything like a sensible dialogue or proper social co-operation between faiths."