Ego-- harmful delusion or pragmatic necessity?

[Mudhammam]

Hmmmm.  Anatta sounds a lot like the OP.

I wonder now what ego is.  Is it just the awareness that with sights and sounds, "someone" is watching those sights and sounds?  Is it a world view where memories and concepts are attached to a name?  Is it an expression of selfish instincts?  Or is it another word that gets too slippery to hold much meaning upon close observation?

"Someone" is defined by boundaries established through mechanisms that typically extend beyond the self-awareness that "someone" has of their "self." It's an arbitrary distinction in the end, but useful, or necessary, as a means of survival and---perhaps by a fortunate accident---so much more which the mammalian brain is enabled to achieve for itself as a result.