  We discuss philosophical issues concerning the notion of cognition basing
ourselves in experimental results in cognitive sciences, especially in computer
simulations of cognitive systems. There have been debates on the "proper"
approach for studying cognition, but we have realized that all approaches can
be in theory equivalent. Different approaches model different properties of
cognitive systems from different perspectives, so we can only learn from all of
them. We also integrate ideas from several perspectives for enhancing the
notion of cognition, such that it can contain other definitions of cognition as
special cases. This allows us to propose a simple classification of different
types of cognition.

Artificial Intelligence