- Perhaps Ehrlich's best known blunder is a 1980 bet he made with University of Maryland economist Julian Simon. Dr. Simon, who believes that human ingenuity holds the answers to population growth problems, asserted that if Ehrlich were correct and the world truly was heading toward an era of scarcity, then the price of various commodities would rise over time. Simon predicted that prices would fall instead and challenged Ehrlich to pick any commodity and any future date to illustrate his point. Ehrlich accepted the challenge: In October 1980, he purchased $1,000 worth of five metals ($200 each) -- tin, tungsten, copper, nickel and chrome. Ehrlich bet that if the combined value of all five metals he purchased was higher in 1990, Simon would have to pay him the difference. If the prices turned out to be lower, Ehrlich would pay Simon the difference. Ten years later, Ehrlich sent Simon a check for $576 -- all five metals had fallen in price.