The ego is not an entity but a trend of behavior of living beings in line with the level of consciousness of each one .
But then dear Peter Russell , does anything including human beings , exist as we pretend it to exist ? Existence as you and others teach , is a very ambiguous term depending more on the observer’s mind than in any sort of "reality" .
We chan refer to the ego in a way that sometimes may make some people think ego is a certain entity for simplicity , but people on the path realises very well , that ego is a mental estate of mind which has to be trascended to have a wider perception of reality beyond emotions and traditional education and culture .
Purest perception is attained as wake up is completed . ( Buddahood in sanscrit )
Brahmason