The Self is a duration which, as the community of self, the time-gap of consciousness cannot break in twain.
The Self is a relation to oneself, or put more abstractly, a relation of force to itself just as power is a relation of a force to other for forces.
The Self is a ghost in that we are all haunted by things inherited from our father and mother that 'walk' in us, and that all sorts of dead ideas and lifeless old beliefs nevertheless cling to us all the same, and we cannot shake them off.
The Self is a delusion insofar as it rests on the belief that one carries oneself forward and experiences the myriad thing. The truth of the matter is that the myriad things come forward and experience themselves.
The Self is (wrongheadedly conceived of by descartes as) a thinking organism... it is taken as the sum-total of all the different faculties which belong to thought (i.e. Imagination, memory, will and understanding.).
The Self is a rhetorical figure and a performative assertion, enacted in specific situations within fields of power, history, and culture.