Monthly Archives: March 2015

Looking at Evolution, Part 5: Evolution in Human History

Today’s Post

Having now seen how Teilhard’s insight that ‘evolution can be seen to proceed through the increase of complexity’ is reflected in the evolution of the human brain, today’s post continues to address how evolution continues to rise in the human person.

The Onset of Laws

As we postulated in the last post, it is probably not an oversimplification to trace the evolution of the human person in terms of developing the skill of using the neocortex brain (reason) to modulate the more primitive and instinctual stimuli of the limbic brain (emotions) and the reptilian brain (aggression and fear).  Works of primitive art dating back to some thirty thousand years ago suggest the first manifestations of this new activity.

Less ambiguous evidence of this skill can be found in the early laws of ancient societies:  guidelines and rules for regulating human behavior to support the stability of society.  The earliest of such laws seems to have emerged in the 24th century BCE, and is known as “The Code of Urukagina”, a Mesopotamian ruler.

Other rulers of the “fertile crescent” also promulgated their laws such as those found in:

The Papyrus of Ani (known as “The Book of the Dead”, Egyptian- 2000 BCE)

The Code of Ur-Nammu (Sumerian- 1900-1700 BCE)

The Code of Hammurabi (Babylonian, approx 1740 BCE)

By the tenth century BCE, it had become common for rulers to document their laws through such promulgations, leading to many examples including the Mosaic Law found in the Old Testament.

All of these codes and laws had one thing in common: they assumed that the most basic human actions were based on needs and desires that required expression and regulation to avoid chaos in society.  They represent the evolution of the human skill of employing the neocortex brain to regulate social behavior in a way different from ‘pre-humans’.  We see this skill evolving even today through religious teachings, cultural norms, ethics and our constitutions and legal systems.

Speed-up on the Evolution Highway

Teilhard notes two profound changes occurring in this neurological-based “change of state”:

  • The speed of physiological evolution in the tree of mammals can be seen to increase as brain size increases and gathers complexity
  • This curve ascends at an even steeper rate as humans emerge and become more skillful in employing the new physiology enabled by this new brain capacity.

A sense of this speeding up of evolution can be seen in this overly simple timeline:

Some fourteen billion years ago:  the Universe is born

Some four billion years ago:  the earth forms

About two billion years ago:  the first cell appears

About two hundred million years ago:  the first mammal appears

Some two hundred thousand years ago:  the first human appears

Nearly twenty six hundred years ago:  the first laws begin to appear

Increase in complexity is obviously gathering speed.  It increases even faster as the human person becomes more complex without having to undergo further neurological mutation.  No doubt our neurological systems are still evolving as such, but at a pace scarcely measurable when compared to the growth that occurs as we become more mature on both a personal level as well as on the levels of culture and society.

Looking at this evolutionary speed-up across the three eras of evolution:

  • In the long and ‘psychically cold’ era of ‘pre-life’, as we saw, evolution proceeds slowly with each small accretion of matter accompanied by slightly increased complexity over immensely long periods of time. While physics and chemistry are able to articulate the forces which unify these decreasingly small granules of the universe, the factors which foster the corresponding increase of complexity are not well understood.
  • In the era of ‘life’, the theories associated with natural selection are equally well understood and address the process of mutation, replication and survival very well. The tree of life, in all its branches, can be seen as an immense groping of the universe in search of increased complexity. This tree represents uncounted billions of replications resulting in unprecedented characteristics of awareness and freedom; uncounted millions of opportunities for mutations to provide candidates for increased energy and activity.   As in the case of ‘pre-life’, however, the mechanism which adds a quantum of complexity to each step of replication and survival is equally as mysterious. The theory of Natural Selection explains the ‘x and y’ dimensions of ‘size’, but it does not address the ‘z’ dimension of ‘rise’.
  • In the human era, evolution is finally freed from the constraints of Natural Selection, and its requirement for large volumes of candidates on which to work its magic of trial and error to achieve increased complexity. In addition to the advent of ‘reflective consciousness’, awareness that we are aware of, comes the influence of what Teilhard refers to as ‘reflexive consciousness’, consciousness which ‘rebounds’ upon itself. Not only are we aware of our consciousness, but such consciousness adds another dimension to our growth: evolution now can be seen to occur in our individual persons. Our own lives are effectively ‘trees of life’, with the billions of thoughts, reflections and intuitions which occupy our brains, stimulated by our instinctual makeup and refined by our intellects, as we slowly develop and refine our stance with respect to reality. This reflexive nature of our consciousness gives us the capability to be aware of the consequences of our actions, and as such to plot these consequences forward in time and prepare for the outcomes. Being able to take these small steps into the future is a measure of our personal growth, and thus speeds up the rise of complexity in our person. Our personal growth itself is nothing less than the continuation of the axis of evolution through each of us.

Something startlingly different is occurring beneath our feet, and we are being carried along by it even as we try to understand it.  I have used this Teilhard quote before, but it gathers meaning as we better understand the process of evolution as it rises through us:

“..I doubt that whether there is a more decisive moment for a thinking being than when the scales fall from his eyes and he discovers that he is not an isolated unit lost in the cosmic solitudes and realizes that a universal will to live converges and is made human in him.”

The Next Post

The next post will continue to examine Teilhard’s perspective on the continuation of evolution through the human person, and look at some of the problems it raises with the adherents of materialism.

Looking at Evolution, Part 4: Human Neurology

Today’s Post

Having now established Teilhard’s ‘axis of evolution’ as ‘complexity’, we can explore how this ascent of complexity is reflected in the evolution of the human brain.

Evolution at the Neurological Level

Paul MacLean (The Triune Brain in Evolution) understands the human brain to have evolved in three overlapping stages or layers: the ‘reptilian’, the ‘limbic’ and the ‘neocortex’.  These three brains successively overlay each other over time, and range from the earliest and smallest brains associated with reptiles and birds, to the mid-sized associated with mammals, to the largest size associated with the ‘higher’ mammals and humans.

  • The reptilian brain is the oldest and least complex. It consists of a bulbous elaboration of the spinal cord and controls the vital life functions of breathing, swallowing, heartbeat and rudimentary sensory functions such as eye tracking. Rudimentary interactions such as displays of aggression and courtship, mating and territorial defense are controlled by the reptilian brain.
  • The limbic brain evolved much later, and occurs only in mammals. It wraps around the reptilian brain, and is considered to be the source of emotive behavior. For example, in contrast to the detachment and disinterest of reptiles to their offspring, mammals enter into subtle and elaborate interactions with their young. Some form close-knit, mutually nurturing social groups (families) in which members spend time caring for one another.
  • The neocortex is the most recent layer of brain and, in humans, the largest of the three. Mammals that evolved long ago, like the opossum, have only a thin skin of neocortex covering the older brains. Neocortical size has grown in mammals of recent origin, such as chimpanzees, even more so, as is evident in their increased cranial capacity. In human beings, the neocortex has ballooned to massive proportions. The specific brain growth step which enabled the jump from animal ‘awareness’ to human ‘knowledge of awareness’ is not clear, but paleontological evidence of uniquely human activity, such as carved human images, suggests a period some fifty to eighty thousand years ago.

Even though more complex brains have emerged ‘on top’ of the older brains, the older brain functions continue to operate.

  • If the limbic and neocortex brains are severely damaged, the reptilian brain will continue to operate the basic bodily functions of the heart and lung, keeping the person clinically alive: a condition known as “brain death”.   The reptilian brain’s reactions to external stimuli (such as the ‘fight or flight’ reflex) are still active in the human, accounting for example for our instinctive reaction to danger.
  • The limbic brain, the seat of emotion, continues to exert a strong influence on human behavior. Instinctual emotions, such as the surge of motherly affection for her newborn child, are both strong and universally found in both humans and mammals.

At some point in the evolution of the neocortex brain one of Teilhard’s ‘changes of state’ occurs.  The consciousness enabled by the neocortex jumps from ‘awareness’ to ‘knowledge of awareness’, and this new ‘reflective awareness’ is the capacity that distinguishes the human entity from that which came before.  As Julian Huxley puts it,

“..human evolution and biological evolution (are) two phases of a single process, but separated by a ‘critical point’, after which the properties of the evolving material underwent radical change.”

The largest neocortex-to-brain ratio of any creature, the true physical reflection of complexity, which results from this step is a truly unprecedented proportion that confers upon us our capacity for reason.

Capacity, yes, but emergence of this larger neocortex brain in humans did not immediately result in a strong ability to reason.  Thousands of years were necessary for humans to begin to learn to utilize the neocortex brain to regulate social behavior in a way different from the ‘pre-human’ animal.  It was necessary for humans to develop the skill of using the neocortex function to modulate the basic, primal, instinctual urges of the more primitive brains such as ‘fight or flight’, aggression, territorial defense and reproduction in pursuit of their need for human relationships.

It is probably not an oversimplification to trace the evolution of the human person in terms of the skillfulness of the neocortex brain (reason) to modulate the more primitive and instinctual stimuli of the limbic brain (emotions) and the reptilian brain (anger and fear).

The Next Post

The growth in physiology addressed in this week’s post speeds up over time, under the continued influence of mutations carried forward by Natural Selection. But as we shall see in the next post, the advent of the neocortex brain with its power of ‘reflective consciousness’ enables influences other than Natural Selection to take precedence.