English philosopher McGinn speaks about the various reasons for not believing in God, and some of the reasons for. He gives a thorough treatment of the ontological argument. In addition, McGinn draws an important distinction between atheism (lack of belief in a deity) and antitheism (active opposition to theism); he identifies himself as both an atheist and an antitheist. Finally, he speculates about a post-theistic society.

Weinberg talks about the effectiveness of the Design Argument, both in the past and today. He also discusses the reasons that people become religious, including the varying influences of physical and biological arguments against religion. Miller connects this to a higher likelihood of biologists being non-believers than physicists, which Weinberg finds surprising.

Weinberg goes on to distinguish between harm done in the name of religion from that done by religion and states that both of these are very real and very dangerous. He goes on to discuss the difference between religious belief in America and Europe, and about how he doesn’t like the "character" of the monotheistic God. He ends by saying that science is very definitely corrosive to religious belief, and that he considers this a good thing.

Jonathan Miller and Arthur Miller talk about disbelief and their experiences of anti-Semitism, recorded in 2004.

Biologist Richard Dawkins talks to Jonathan Miller about his implacable opposition to all religion.

Christian theologian Denys Turner defends the case for God as the answer to the most important questions.

American philosopher Dennett explains why he called one of his books Darwin's Dangerous Idea, and why many of Darwin's contemporaries, in particular, considered Darwin's theory of evolution to be dangerous. He goes on to deal with the question of consciousness (i.e., is the consciousness/soul distinct from the body), talking about Darwin's rejection of the soul and the possible origins and psychological purposes of a belief in an immaterial soul.

Next, he talks about his Christian upbringing and how he became an atheist. He goes on to ask why it is thought rude to criticise religious belief, and suggests that it is due to the influential status of the religions in question. He finishes by wondering whether we could live effectively in a post-theistic world.