Paul Sabin of Yale University and author of The Bet talks with EconTalk host Russ Roberts about his book. Sabin uses the bet between Paul Ehrlich and Julian Simon--a bet over whether natural resources are getting scarcer as population grows--as a lens for examining the evolution of the environmental movement and its status today. Sabin considers the successes and failures of the movement and the challenges of having nuanced public policy discussions on issues where both sides have passionate opinions.