Um, I don't think I'm concerned with "complexity" as such. It's more like...

Consider the Newtonian universe. "This place" is a euclidean space full of little billiard balls bouncing back and forth. You can point at some subset of the universe and say "that's me". If I ask "why am I seeing [something]?" you can answer that with "because that thing there is a brain, the one computing your experience of consciousness, and it is attached to eyes which happen to be looking at [something]". I guess, it's reductionist.

In the AIXI/instrumentalist model, "sensory input" doesn't seem to reduce to anything else, and the self is "taken for granted". Doesn't that bother you?