If Richard Dawkins made this, then I’ve just lost some confidence in his logic.
Theism and its opposite — atheism — have little to do with a belief about whether there is a god or not.
Theism is not simply the belief that there is a god. Theism is the belief that there is a god who can be influenced by his human believers. (What good is a god who doesn’t change stuff anyway? Can’t make any money on that kind of god, can we?)
Atheism, on the other hand, is not by definition the belief that there is no god. Atheism is only the belief that no matter how much you sing, dance, grovel on your knees, cry, weep, scream, shout, mutter under your breath, or swing incense, there ain’t no god who is giving a single shit about it.
So, that doesn’t mean that atheists must believe there is no god. It just means that if there is a god, atheists believe he’s not listening to you. He doesn’t give a shit about you or your prayers. He doesn’t engage in do-overs. He doesn’t come to your rescue. He doesn’t give you your daily bread, or cure your illnesses, or decide who wins your goddamn football games.
To an atheist, the likelihood of the existence of, for instance, the God of Abraham, is approximately equal to the likelihood of a giant tortoise carrying the earth on its back, or the Flying Spaghetti Monster, or Zeus, or Apollo, or any other of the thousands of deities we’ve created, or any other random explanation made up of whole cloth from zero evidence by illiterates sitting around a campfire.
But whether such a disinterested deity exists or not doesn’t actually matter. An uncaring, unresponsive god has absolutely zero effect on the laws of physics, and thus, it has zero effect on our lives.
So an atheist does not have to believe there is no god. An atheist only has to believe that there is no god who is subject to influence by human believers.