I didn't think it was possible to make a movie this Hansonian and no they never waver. The basic premise is "a comedy set in a world where no one has ever lied." People speak the truth to each other in unbiased fashion and every channel on TV is some version of The History Channel. You then see, step by step, why this is not a Nash equilibrium and you observe, as the title indicates, "the invention of lying," including under conditions of altruism. Along the way, you see a theory of the origins of religion, a portrait of how the world would look if no one signaled, a redo of Geoffrey Miller on The Mating Mind, and hints at the idea of ESS. It's a "remarkably radical comedy" (Ebert) and the gushy parts have hidden venom.