The fourth chapter of Dubner and Levitt's Superfreakonomics, The Fix is ​​in, discusses how the modern world has improved significantly compared to the past. Even though people continue to complain about exactly the opposite, the authors set out to explain that the world has actually improved and that simple, cheap solutions to expensive problems are the reason. The chapter begins with the authors providing, for example, the problems of the past; death in pregnant women caused by puerperal fever. In this case, the responsibility for having contracted the disease was attributable to the infected women. However, in the following years, a lot of research was conducted and it was suggested that the problem actually lay in the medical department. The solution to this problem was equally simple and economical. The concepts related to Dubner and Levitt's Superfreakonomics - What Al Gore and Mount Pinatubo have in common are also rationality and cost, marginality and opportunity, as well as maximization of satisfaction. According to Barbiero's lesson in chapter one of The New World of Economics, rationality means getting more of what you want and less of what you don't want. It would be rational for someone who is hungry to purchase food to eat. In this case, the individual wants food and does not want to be hungry. Therefore, eating this meat is rational because it satisfies their needs at that time. Even knowing that consuming what are called “ruminants” contributes to global warming, some may still choose to consume it in moderation. Perhaps they choose to consume meat occasionally and only in limited quantities. If people stopped eating meat, there would be less need for ruminants. Fewer ruminants would mean ridding the world of some of the gases they produce that contribute to global warming. However, many people may not see a problem with their hot environment, so they would not see a reason to change their behavior from meat-eating to meat-eating.