Ancient man had no consciousness of self, according to Julian Jaynes, in his masterpiece of research and speculation, The Origins of Consciousness in the Breakdown of the Bicameral Mind. Jaynes argues that ancient man did not recognize the voice inside his head as his own, attributing that voice to God (or to the gods). It was only when man learned to attribute that inner voice to himself, Jaynes speculates, that we became conscious of self and others in the sense that we mean those terms today.
Whether or not we accept Jaynes’s hypothesis, what should be obvious is that our inner voice has enormous influence over our behavior and our experience. We spend most of our waking hours talking to our self, telling our self what to think and how to feel. It is, I believe, why we cherish those moments when we manage to turn off that inner monologue. Without an inner voice telling us what to think and feel, we experience the world directly.
When I am writing fiction, the distinction between self and other disappears and I experience a world (albeit a fictional world) directly. The inner voice comes neither from me, nor from God. It comes from a fictional character who reveals that voice to me, who shares that voice with me and bestows on me both the privilege and the responsibility to tell the story. There is a certain exhilaration that comes to me at those moments. It is why I write fiction.