"This book is about self-control. I nevertheless begin with a few words on cognitive ability - or what in everyday life is often referred to as "intelligence." To say that people differ in cognitive ability is stating the obvious. It is a basic fact of life. A well-ordered society accommodates these differences, for instance by providing different educational tracks and employment opportunities, some cognitively more demanding than others. It would be absurd to require all children to attain the highest educational level and obtain a university degree. It would be equally absurd to expect all adults to be able to do the intellectually most difficult work. This is reflected in our morality. Nobody blames people of only modest cognitive ability for not reaching the top of the educational or labor market ladder. This capacity is not a matter of volition, but largely determined by genes and early upbringing. Since both genetic inheritance and childhood family environment are beyond our control, it would be unfair to hold anyone fully responsible if, as a result, they do less well in life than others-just as it would be unfair to blame a five-foot-tall youth for not being a top basketball player"--