  It is helpful in considering this question to employ a distinction like Berkeley’s between ideas and notions. Ideas are the objects of our mental acts, and they capture  transparently – ‘by way of image or likeness’  (Principles, sect. 27) – that of which they are the ideas.  The self and its faculties are not the objects of our mental acts, but are captured only obliquely in the performance of its acts, and of these Berkeley says we have notions, meaning by this that what we capture of the nature of the dynamic agent does not seem to have the same transparency as what we capture as the normal objects of the agent’s mental acts. It is not necessary to become involved in Berkeley’s metaphysics in general to feel the force of the claim that the contents and internal objects of our mental acts are grasped with a lucidity that exceeds that of our grasp of the agent and the acts per se. Because of this, notions of the self perhaps have a ‘thickness’ and are permanently contestable: there seems always to be room for more dispute as to what is involved in that concept. (Though we shall see later, in 5.2.2, that there is a ‘non-thick’ way of taking the Berkeleyan concept of a notion.)