One problem with artificial imtelligence is that we do not fully understand human intelligence. The definition of artificial intelligence used in the book is about behaviour that would be 'considered to require intelligence in humans' ... but what is that! This is one reason why the Turing test is couched as a sort of matching competition, we do not need to define 'intelligence', merely not be able to tell the difference from a human. However, it is also clear that computers can do things that humans can't, such as huge calculations; and also that humans have many abilities, both rational and emotional, that (at least currently) AI does not. That is one reason it may be useful to sometimes thing of AI as alien intelligence -- complimentary rather than competing with human intelligence.
Defined on page 3
Used on pages 1, 2, 3, 5, 6, 8, 109, 202, 221, 222, 554, 555, 560, 585