intelligence
the capacity to acquire and apply knowledge" or "the faculty of thought and reason" or "the ability to comprehend and profit from experience.

" "the ability to apply knowledge in order to perform better in an environment."

artificial intelligence
the study and construction of agent programs that perform well in a given environment, for a given agent architecture.
agent
entity that takes action in response to percepts from an environment
rationality
the property of a system which does the "right thing" given what it knows
logical reasoning
the process of deriving new sentences from old, such that the new sentences are necessarily true if the old ones are true
Are reflex actions (such as flinching from a hot stove) rational? Are they intelligent?Rational, yes. Intelligent, no.

You move your hand quickly because it makes sense (rational), you wouldnt want to continue to burn your hand.

Yes, they are rational, because slower, deliberative actions would tend to result in more damage to the hand. If "intelligent" means "applying knowledge" or "using thought and reasoning" then it does not require intelligence to make a reflex action.
To what extent are the following computer systems instances of artificial intelligence: • Supermarket bar code scanners.
Although bar code scanning is in a sense computer vision, these are not AI systems.

The problem of reading a bar code is an extremely limited and artificial form of visual interpretation, and it has been carefully designed to be as simple as possible, given the hardware.

Web search engines.
In many respects. The problem of determining the relevance of a web page to a query is a problem in natural language understanding, and the techniques are related to those we will discuss in Chapters 22 and 23. Search engines like Ask.

com, which group the retrieved pages into categories, use clustering techniques analogous to those we discuss in Chapter 20. Likewise, other functionalities provided by a search engines use intelligent techniques; for instance, the spelling corrector uses a form of data mining based on observing users' corrections of their own spelling errors. On the other hand, the problem of indexing billions of web pages in a way that allows retrieval in seconds is a problem in database design, not in artificial intelligence.

Voice-activated telephone menus.
To a limited extent. Such menus tends to use vocabularies which are very limited -e.

g. the digits, "Yes", and "No" —and within the designers' control, which greatly simplifies the problem. On the other hand, the programs must deal with an uncontrolled space of all kinds of voices and accents. The voice activated directory assistance programs used by telephone companies, which must deal with a large and changing vocabulary are certainly AI programs.

Internet routing algorithms that respond dynamically to the state of the network.
This is border line.

There is something to be said for viewing these as intelligent agents working in cyberspace. The task is sophisticated, the information available is partial, the techniques areheuristic (not guaranteed optimal), and the state of the world is dynamic. All of these are characteristic of intelligent activities. On the other hand, the task is very far from those normally carried out in human cognition.