http://www.guardian.co.uk/science/2010/oct/03/fred-hoyle-nobel-prize
... was simply "the most outrageous prediction" ever made in science. "If [the 7.65 MeV state] did not exist, Hoyle reasoned, the universe would contain no carbon. And if there was no carbon, there would be no human beings. Thus Hoyle was saying – and nobody had ever used logic as outrageous as this before – that the mere fact he was alive and pondering the question of carbon was proof the 7.65 MeV state existed."

http://reading.academia.edu/PatParslow
http://brains.parslow.net/node/1569
The problem is, we can never know exactly what stimuli someone (or something) else is experiencing, nor can we know what the sum-of-experience is that provides them with their own internal models.  Even if we are entirely behaviouristic animals the simplest way of modelling the Other is to ascribe some form of free-will and self-awareness to them.  It is a black box model, which allows our own internal modelling systems to take some shortcuts and guess what their behaviour will be on the basis of some abstractions from previous experience; a parameterisation of the 'other' to allow us to make timely predictions of what they might do next.
I think we do that, at least to a large extent, before we come to be fully self-aware of ourselves.  Furthermore, I think we then go on to model our own 'self' in the light of those we have grown up amongst.  This seems to be borne out by the rare cases of feral children which have been adequately reported, and it seems to be a relatively energy efficient way of organising our minds - we only need to develop the sense of self and ability to be independent once we start getting to a stage where we are also physically capable of surviving on our own.
So my thesis is that we have an emergent consciousness, coming out of a system which models other agents for the simple survival need of having to know what they are going to do, and then through self-similarity we recognise that we are similar to them, and consequently re-use the same modelling technique to provide ourselves with a model of our own minds.