Abstract
In this paper I expose and analyze the berkeleian proposal of notional knowledge. Among
other things, this proposal represents Berkeley´s attempt to know the mind or spirit, that is,
the thinking and active thing that, by its own activity, results unrepresentable as idea. As such
knowledge is already mentioned in the Philosophical Commentaries I will refer to them to
know the origins of that proposal. However, as notional knowledge appears in more detail in
later works I will make use especially the Treatise to tackle the complex notional doctrine.