These nineteen posts have been from "Believing the Unbelievable: The Clash between Faith and Reason in the Modern World," a talk given by Sam Harris on July 4, 2007, at the Aspen Ideas Festival. The nitty gritty:

Let’s get this straight.

Jews, Christians, and Muslims claim that their holy books are so profound, so prescient of humanity's needs, that they could have been written only by the omniscient being who is the creator of the universe.

An unbeliever is simply a person who has entertained this claim, read the books, and found this claim to be ridiculous.