1. The start of Section 2.3 argued that it was impossible to build a representation of a world independently of what the agent will do with it. This exercise lets you evaluate this argument.

Choose a particular world, for example, the things on top of your desk right now.

(a) Get someone to list all of the individuals (things) that exist in this world (or try it yourself as a thought experiment).

(b) Try to think of twenty individuals that they missed. Make these as different from each other as possible. For example, the ball at the tip of the rightmost ball-point pen on the desk, the part of the stapler that makes the staples bend, or the third word on page 1b of a particular book on the desk.

(c) Try to find an individual that cannot be described using your natural language (such as a particular component of the texture of the desk).

(d) Choose a particular task, such as making the desk tidy, and try to write down all of the individuals in the world at a level of description relevant to this task.

Based on this exercise, discuss the following statements.

(a) What exists in a world is a property of the observer.

(b) We need ways to refer to individuals other than expecting each individual to have a separate name.

(c) Which individuals exist is a property of the task as well as of the world.

(d) To describe the individuals in a domain, you need what is essentially a dictionary of a huge number of words and ways to combine them, and this should be able to be done independently of any particular domain.