The history of man has been shaped by many factors, but for our purposes there are three events whose impacts we live with every day.
First of all, about 3 million years ago, the Isthmus of Panama rose up out of the water to prevent a horizontal flow of water between the Atlantic and Pacific oceans. For hundreds of millions of years before this – a long time – the Earth experienced a weak flow of water around the globe from west to east. Temperatures were stable with less variation between the seasons.
But when the Isthmus arose, the flow became routed up along the eastern edge of the US and then out to sea, where it wound back toward Europe and eventually dissipated off the coast of Greenland. These waters, which were warm and which had evaporated a good deal of their volume during the trip, became denser than the surrounding waters from increased salinity. They sank down into the cold depths and began a long return loop back to the other “end” off the coast of India and Australia, where the cold water wells up and affects the climate there. This long loop of water, with planetary effects in heating and cooling areas, is today known as the Northern Atlantic Conveyor.
The practical result of this changed flow was a change in the Earth’s climate from the steady-state regime that had lasted for so long. The climate developed two distinct modes: the warm state, which we are currently in, and the cold state, known as an “ice age”. These states are metastable; once in one state or the other various feedback systems tend to keep the climate in that state until conditions build up to force the climate out of its “comfortable” position in a swing over to the other state. Curiously, if the warm state gets too warm, corrective feedback can tip the scales into an ice age, and vice versa – this is how most of the switches happened, and may be happening now.
Some, such as Dr. William Calvin, think that human intelligence evolved rapidly under the impact of such rapid change. We think that if an ice age descended on our world, that the human race would collapse. Possibly, but it would probably not die – humanity has survived over 200 ice ages.
The second challenge that shaped the human experience was the detonation of Mt. Toba on the island of Sumatra. This was an explosion of a supervolcano, like others in India or Yellowstone Park in the USA, which caused a “volcanic winter” at least six years long, followed by a very cold 1000-year ice age. Conditions were so dire that biologists who have studied the human genome can state with great confidence that the human race was destroyed down to less than 10,000 individuals during this period, and that all people today are descended from those 10,000. Needless to say, the challenge of living through this disaster boosted the intelligence and survival power of humanity. (See the Mt. Toba disaster.)
The third challenge was the most important. Depending on who is telling the story, the human race experienced a physical mutation either 40,000, 26,000, 20,000, 16,000, 12,000, 10,000, or 6,000 years ago. This mutation stopped most of the interaction between the two sides of the human brain, which up until this point had worked together. More importantly, the life experience that our ancestors had was different in type and quality to our own experience. Before the mutation, we were brilliant animals without consciousness as we understand it today. We had awareness of our lives as they unfolded, and we received guidance from our experience and from instinct without differentiating between the two (See Julian Jaynes’ theories about the “Bicameral Mind” for a closer look at these phenomena.)
Once the connection was cut, the two sides of the brain continued to function, and even to work together to some degree, but the quality of experience was much different. Specifically, we now had what we call reflective consciousness, which is awareness of awareness. The importance of this should not be underestimated. Reflective consciousness made us able, for the first time, to be critical of our own thinking processes, by being able to separate from our viewpoints and manipulate them in different ways. This mutation made all of human culture possible. In particular, it made the scientific method possible, and so is responsible for the technology that has brought us to where we are today.
This mutation was absolutely essential to the development of man. It was also dangerous beyond comprehension, and it is not yet clear if mankind can survive the impact and unintended consequences of the change.
The problem with reflective consciousness is the same as its inestimable value: it allows humans to have a point of view about the contents of consciousness. Specifically, it allows belief.
Once we developed the ability to hold perceptions at arm’s length, as it were, and examine them, we became able to consider abstract ideas in the same way, and we became liable to confuse mental constructs with actual sensory reports from the world around us.
These abilities lead to lots of theorizing with a multiplicity of incorrect theories for every accurate one. Worse, emotional evaluations are also factored into the theorizing, with beliefs offering the reassurance of certainty in a forest of doubt. As brilliant animals, we were protected by instinct and kept in obedience; sin was impossible. As men, we can do whatever we can figure out how to do. The goal of life is to regain the unity of the pre-conscious state, but as an adult consciousness able to move between analytical consciousness and experiential awareness smoothly and at will.
This is complicated by the combination of attraction and repulsion we have for the unconscious, but aware, state. It has the deep appeal of the womb, security, freedom from worry, freedom from choice, and stability. On the other hand, consciousness realizes how vulnerable this state is when faced with competition from human consciousness, and fears descent into the animal. On the third hand, something within us recognizes, dimly or otherwise, that there is a reality behind and beyond both these viewpoints, and it is that which calls to us…
But for those obstinate questionings
Of sense and outward things,
Fallings from us, vanishings;
Blank misgivings of a Creature
Moving about in worlds not realised,
High instincts before which our mortal Nature
Did tremble like a guilty Thing surprised:
But for those first affections,
Those shadowy recollections,
Which, be they what they may,
Are yet the fountain light of all our day,
Are yet a master light of all our seeing;
Uphold us, cherish, and have power to make
Our noisy years seem moments in the being
Of the eternal Silence: truths that wake,
To perish never;
Which neither listlessness, nor mad endeavour,
Nor Man nor Boy,
Nor all that is at enmity with joy,
Can utterly abolish or destroy!
Hence in a season of calm weather
Though inland far we be,
Our Souls have sight of that immortal sea
Which brought us hither,
Can in a moment travel thither,
And see the Children sport upon the shore,
And hear the mighty waters rolling evermore.
– Ode: Intimations of Immortality from Recollections of Early Childhood, Wm. Wordsworth