In that context, the alternation of inner voices indicates you aren’t coming to a quick equilibrium in your response. So the illusion of unitary consciousness is broken, or at least disturbed. I’m happy my post has that effect.

I do think consciousness is normally “a conversation with its environment” (good phrase). When it comes to equilibrium quickly we aren’t aware of the conversation; when we have trouble “settling” the conversation itself becomes a focus of awareness.

“Natural” selection occurs on three levels that I can see. (The quotes are because the environment of selection is pretty special.) First, there’s some competition and coalition building among brain regions in the very short term emergence of an equilibrium. As you say these brief periods where one coalition dominates are punctuated (perchings in William James’ phrasing); they dissolve and a new coalition forms, with an unconscious transition in between (unless you are an experienced meditator and are practicing mindfulness).

Second, there’s a local adaptive process over many time scales, as parts of the brain get better at specific sorts of “conversations with the world” and with each other. It is a bit of a stretch to call this selection but it is adaptive and fits into evolutionary models. We normally think of this as “learning” but it isn’t much like learning facts, and indeed parts of the brain grow and even lay down new connections between separate regions (on the longer time scales).

Third is social selection — our behaviors are selected in conversation with other people. Your reference to conversations in the head makes shows how these processes overlap and echo each other.

More on topic, I initially thought about conciousness because I wonder if how this rationality optimization from noise theory can have insights into how subjective consciousness emerges too. Also if there are natural selection elements to it -because it reminds me of how functional organisms can emerge from relatively noisy, relatively random, mutations of DNA through the process of natural selection, and how natural selection may play a role in brain development and in particular in the development of synaptic pathways.