  We will consider all policies of the agent and will prove that one of them is
the best performing policy. While that policy is not computable, computable
policies do exist in its proximity. We will define AI as a computable policy
which is sufficiently proximal to the best performing policy. Before we can
define the agent's best performing policy, we need a language for description
of the world. We will also use this language to develop a program which
satisfies the AI definition. The program will first understand the world by
describing it in the selected language. The program will then use the
description in order to predict the future and select the best possible move.
While this program is extremely inefficient and practically unusable, it can be
improved by refining both the language for description of the world and the
algorithm used to predict the future. This can yield a program which is both
efficient and consistent with the AI definition.
