Why? There are any number of systems in nature which have positive, negative or complex feedback loops within them - why can consciousness not be a pattern of brain activity, and self-awareness not be a 'sub-harmonic' in that pattern?
O.
Any product produced by a pattern of activity is just an end reaction to that activity defined by another observed pattern of sub atomic particles. Consciousness is not defined in terms of a reaction. It is perception.
Consciousness is not easy to define but it certainly includes perception. When a gazelle sees a lion creeping up on it that is conscious perception. The gazelle, by the way, does not need to have a little gazelle inside it to make sense of the patterns of incoming information to recognise it as something scary and gazelle-eating; that is what the brain does.
I know we struggle with mind/body. Try thinking of it like this : every thing in the cosmos has a subjective
aspect, and an objective
aspect when viewed from somewhere else. Thus I can say 'I am', but someone else referring to me would say, 'he is'. Both are equally valid statements. Mind and brain are essentially two aspects of the same thing. Rather like a lens will
focus sunlight, what a brain does, is to focus subjectivity, it creates a highly refined and enriched region, or focal point, of subjectivity. Thus in contrast to a stone or a twig or a skyscraper, a brain manufactures a very rich sense of 'being' or 'am' ing and the first-person subjective aspect of that is what we call mind.