A "rational agent" is one that does the right thing - means in the table for the agent function is filled out correctly.

Doing the right thing is better than doing the wrong thing.

Right action is the one that will cause the agent to be most successful. Therefore we will need to some way to measure success.

Performance measure:

A performance measure embodies the criterion for success of an agent's behavior which an agent is plunked down in an environment, it generates a sequence of actions according to the percepts it receives this sequence of actions causes the environment to go through sequence of states. If the sequence is desirable, then the agent has performed well. There is not one fixed measure suitable for all agents. We could ask the agent for the subjective opinion o ow happy it is with its own performance, but some agents would be unable to answer, and other would delude themselves.

Example, vacuum - cleaner agent.

We might propose to measure performance by the amount of dirt cleaned up in a single hour shift.

A rational agent can maximize this performance measure by cleaning up the dirt, then leaning it up again and so on.

It is better to design performance measures according to what one actually wants in the environment, rather that according to how one thinks the agent should behave.

Rationality.

What is rational at any given time depends on four things:

1] The performance measure that defines the criterion of success.

2] The agents prior knowledge of the environment.

3] The action that the agent can perform.

4] The agent's percept sequence to date.

This leads to a definition of a rational agent :

“For each possible percept sequence, a rational agent should select an action that is expected to maximize its performance measure, given the evidence provided by the percept sequence and whatever built in knowledge the agent has”.

Omniscience, learning and autonomy.

A omniscient agent knows the actual outcome of its actions and can act according buy omniscience is impossible in reality. Rationality maximized expected performance, while perfection maximizes actual performance.

Our definition of rationality does not require omniscience then because the rational choice depend only On the percept sequence to date.doing actions in order to modify future percepts – sometimes called information gathering – is an imp part of rationality. Our definition requires a rational agent not only to gather information but also to learn as much as possible from what it perceives. The agent initial configuration could reflect some prior knowledge of the environment but as the agent gains experience this may be modified and augmented. There are extreme case in which the environment is completely known a prior.

To extent that an agent relies on the prior knowledge of its designer rather than on its own percepts, we say that the agent lacks autonomy.

A rational agent should be autonomous it should learn what it can to compensate for partial or incorrect prior knowledge.

Example: A vacuum cleaning agent that learns to foresee where and when additional dirt will appear will do better than one that does not.