Artificial Intelligence, in light of this definition of intelligence, is simply the application of artificial or non-naturally occurring systems that use the knowledge-level to achieve goals. A more practical definition that has been used for AI is attempting to build artificial systems that will perform better on tasks that humans currently do better. Thus, at present, tasks like real number division are not AI because computers easily do that task better (faster with less error) than humans. However, visual perception is AI since it has proved very difficult to get computers to perform even basic tasks. Obviously, this definition changes over time but it does capture the essential nature of AI questions.