Theory is not as exciting as trying to capture the thinking of our ancestors. General readers may find that this chapter takes some pondering. I believe it is worth the effort. Among other things, it gives my views on what will advance our knowledge of intelligence. There is a section on how a chimpanzee defeats humans on an important cognitive task. Have faith: later on we will be discussing things like how people can enhance their mental abilities (the advice is pretty common sense but worth taking), the fate of convicts on death row, and whether we can achieve the wisdom needed to cope with the problems of the twenty-first century.

I am going to stress the limitations of g but feel a certain reluctance to do so. Arthur Jensen has done brilliant work in exploiting its potential, and virtually everything I have done in psychology has been a response to problems and challenges posed by Jensen. His theory has a great beauty rather like that of Plato's theory of Forms. But I am now convinced that we must transcend a g-ocentric approach to make further progress.