An Extended Metaphor

The sun rises above a wide, deep ocean. Facing the sun, we stand on the shore of a still darkened continent. In the darkness behind us and below the horizon, the continent on which we stand joins the ocean that we now confront. Our preconscious ancestors came from the ocean and traversed the continent, their sight growing as the light increased. We explore the ocean and continent, knowing little about either.

The sun: the growing light of consciousness.
The ocean: the water of life; the objective universe that pre-existed our subjectivity.
The darkness behind us: preconscious organismic responses and unconscious mental processes without which we would not be conscious.

Statements about the "darkness", the origins of consciousness, are experiential, evidenced or traditional. Buddhist teaching is mainly experiential although it receives the rebirth idea from tradition, unless, of course, the line between experience and tradition is not drawn where I think it is. By contrast, the religious teaching in which I was indoctrinated was merely traditional and thus, I suggest, perpetuated the darkness. People continued not to understand how they had become conscious. 

Did human consciousness result from increasing organismic sensitivity to environmental alterations or from the infusion of souls into already conscious animal bodies - or indeed into mechanistically unconscious animal bodies, according to Cartesianism? The idea of souls may be remotely derived from the experience of dreaming, thus from the experience of (apparently) leaving the body temporarily in sleep and permanently in death, but it is contradicted by later evidence that dreams result from sleeping brain activity. Buddhist meditation, direct experience of psychological processes, generated a no soul teaching.

Some explorers sail the ocean. Others shine light into the darkness from which we emerged. Our ancestors originated from the environment that now confronts us. Eventually, those exploring in opposite directions will meet.