She believes that if people act in their own self interest they will be more productive and efficient in order to come out on top of the other self interested individuals. When everyone does this together they make more things we want and make them better.
 The is obviously quite flawed. The principle issue is who is going to set the rules and draw the line where the rat race starts. Why shouldnt a selfish person break the rivals ability to compete. and what of those who have already reached the top whats to stop them using their power to shoot down up and coming rivals using violence and coercion like drug lords. How are those who are poor supposed to compete with people born with access to private schools, tuition and middle class cultural capital. As a result of this in the real world we have created the state and government who are given a monopoly on voilence to restrain the powerful from acting like drugs lords, making rules about how we can compete fairly and setting at least some standards of family and school life to help nurture people to become competitive and productive