Perhaps the best way to understand the psychology of radicals is to read accounts of former believers. In that classic collection of essays by disillusioned communists—The God That Failed—six major writers evoke what passionate belief feels like and analyze the kinds of thinking that sustain it. In the opening selection, Arthur Koestler describes the heady moment when “the new light seems to pour from all directions across the skull; the whole universe falls into pattern like the stray pieces of a jigsaw puzzle assembled by magic at one stroke. There is now an answer to every question, doubts and conflicts are a matter of the tortured past” when one still lived among “those who don’t know.” One has at last achieved complete serenity and assurance, except for the “occasional fear of losing faith again, losing thereby what alone makes life worth living.”

The most important lesson Koestler learned was what might be called “preemptive refutation,” a series of techniques guaranteed to handle any counter-evidence. When, as a novice reporter for a communist paper, he pointed out that every word of a major story was false, the editor explained that Koestler still had the “mechanistic” outlook instead of the proper dialectical one revealing what was “objectively” happening. Once you have assimilated dialectics, Koestler explains, “you were no longer disturbed by facts,” which fell automatically into place. The only remaining difficulty was adjusting to a rapid shift in the party line. Then you had to search