Some of us are fortunate enough to inherit great material wealth from our forebears. Others of us are content to know that our ancestors achieved lesser remarkable things (in materialistic terms), perhaps making great discoveries, exploring unknown territories or achieving excellence in art, or sport or music. Most of us can remember a grandparent with admirable qualities we would be happy to emulate and parents who suffered great privations and sacrificed a good deal to further our welfare. But our memories of our predecessors and how much we owe them is woefully inadequate.

If I asked you to tell me those that most influenced your thinking and your behaviour, for example, you would most likely reference friends, relatives and significant role models that have influenced you. And no doubt it is true that such people have impacted on the way you think and behave.

But there is an underlying platform for your thinking and behaviour that is much more ancient. The evolutionary process that commenced 4.5 billion years ago with the commencement of life on earth can be traced through a process that the Jesuit philosopher and palaeontologist Teilhard de Chardin termed “complexification”.

The first examples of life on earth were simple single-celled organisms. But as evolution weaved its magicover the millenia more and more complex organisms evolved. for many millions of years the forefront of evolution was marked by the reptiles many of which species are so successful that they endure with us to the present day.

So all these eons after, we still have snakes and lizards, crocodiles and turtles with an enduring place on this earth. And why is this so? Well it is because these reasonably primitive animals, with only the most basic brain components have evolved successful survival strategies. And although we don’t give it much conscious thought we share many of their attributes.

Reptiles have survived because they are proficient at finding food, defending territory and procreating. Most reptiles lay multiple eggs and except for a few species (notably crocodiles) abandon their hatchlings to fend for themselves once the eggs are hatched. As far as we can tell they have no emotions, don’t engage in play, and display little nurturing capacity.

But soon (in evolutionary time of course – just after a few squillion years!) the reptiles were supplanted as the dominant animal form by the mammals. It is instructive to look at how mammals differ from reptiles, not so much in their physical aspects, but how they think and behave.

In contrast to reptiles, mammals display emotions. In contrast to reptiles they give birth to young that are immature and vulnerable and as a result must be nurtured. Because the young of mammals are immature, they must learn over a period of time how to deal with the world before they can set out independently to lead their lives. Certainly they are born with some innate instincts, but compared with reptiles they need to address their comparative vulnerability by learning coping and survival mechanisms. Playfulness provides young mammals with practice in adult behaviours and promotes bonding. The emotional responsiveness of mammals is appealing to us and no doubt partially explains why more of us prefer to keep cats and dogs as pets rather than lizards! Mammals also have enhanced memory capacity compared to reptiles.

But of course evolution continues to move onward. In very recent evolutionary times (in the last blink of the evolutionary eyelid) it has succeeded in manufacturing hominids and we egotistically claim that its crowning success is the evolution of mankind. How does mankind differ from its reptilian and mammalian predecessors in thought and behaviour? Well, we do so in many ways but evolutionists would attribute our differences to the rapid development of the brain, the swelling of the neocortex and in particular the development of the frontal lobes.

The additional capabilities that this innovation made available are reason, imagination, planning, empathy and the unique human need for meaning and purpose.

The interesting thing about this continuous evolutionary progress from reptile, to mammal, to human, is that each succeeding development did not supplant what went before but overlaid it. When the neuroscientist Paul Maclean described the human brain in his paper “The Brain in Relation to Empathy and Medical Education” in 1967, he coined the term The Triune Brain. He pointed out that although we are blessed with the development of the frontal lobes and so on embedded in our brain structure we still have the reptilian brain which is located in the brain stem and the amygdala, and the paleo-mammalian brain which is located in what has come to be called the limbic system. Maclean using a colourful turn of phrase suggested that when a man lies down on the psychiatrists couch he is in fact lying down alongside a horse and an alligator! As a result of this whilst we might be beneficiaries of the most recent evolutionary development of the brain, we still have to contend with the older parts.

The author and philosopher, Arthur Koestler, maintained that the prime flaw and ultimate vulnerability in humankind occurs because evolution has built these successive brain components so quickly that they are not well integrated and are deficient in their ability to communicate with each other. In his book From Bricks to Babel, Koestler described the dilemma thus:

“On one side the pale cast of rational thought, of logic suspended on a thin thread all too easily broken; on the other, the raging fury of passionately held irrational beliefs, reflected in the holocausts of past and present history.”

But Koestler’s statement overplays the problem somewhat. Firstly there are myriad connections between all these elements of the brain and whilst they might not connect perfectly they certainly communicate extensively with one another. Secondly Koestler implies that somehow we are at the mercy of “passionately held irrational beliefs” and this is not necessarily true.

We have learnt from previous blog postings that we do not have to be irrational responders to our baser emotions. Indeed the pursuit of “mindfulness” provides an effective defence against such unthinking responses.

But we must also guard against throwing the baby out with the bathwater. It is far from proven that a cold emotionless response to the world is the most rational way of dealing with it. Indeed the neuroscientist Antonio Damasio (author of Descartes Error) proposes that emotions are not a luxury or an unnecessary distraction due to our fragmented evolutionary development- they are essential to rational thinking and to normal social behaviour. He argues that the human intellect is enhanced by the interconnectedness of the various brain functions and not as Koestler would have us believe diminished by insufficient connectedness.

It would seem then more likely to me that human effectiveness is improved by the ability to access and take advantage of the various brain capacities of our evolutionary history. If there is dissonance – and that would be unhelpful – we have effective mechanisms of dealing with it.

 

It is easy enough to demonstrate (see for example The Humanizing Brain by James Ashbrook and Carol Albright) that the reptilian and neo-mammalian brains still confer benefits on us. There is some evidence that the rapid development over evolutionary time of our principal brain components may have caused difficulties for us but this is not confined to this physical development. Consider, for example, the late evolutionary development of hominids learning to walk upright and how that has contributed to our propensity to have bad backs! And just as some of us succumb to this physical impairment, some of us succumb to behaviours which our reptilian and neo-mammalian brains dispose us to without reasonable mediation by our rationality.

But notwithstanding this, the hard-wired genetic learning passed on by our ancestors over vast millennia still strongly influences our behaviour. The influence of our conscious thinking triggered by the tremendously rapid growth of the cerebral cortex sometimes cannot compete with the stored responses learnt by our ancestors over the eons. When we ponder on how little of that learning was acquired in relatively recent social communities, it becomes apparent that much of that genetic learning could be now inappropriate for modern society.

 

For example the physiological responses of flight or fight were useful strategies when the environment threatened immediate physical harm and dangers were prevalent. Then life was short and these physical responses aided us significantly in avoiding premature death. In modern societies, where the environment is much more benign and life spans are significantly enhanced, the physiological triggers of those physical response mechanisms can lead to hypertension and various cardiovascular diseases that now paradoxically reduce our life spans.

 

So it is that much of what we have inherited genetically derived over the millennia, because it aided survival in ancient times where the physical environment was much different, can often be an encumbrance to us in modern society. As an example, most of us have instinctual fears of snakes and spiders. These were useful reactions when we were hunter gatherers. It might be more beneficial in modern society to have instinctual fear of power sockets or speeding motor vehicles which are in modern times more likely to cause death. But these dangers have only been present for perhaps a century. This has not been enough time for genetic selection to have adjusted to appropriate adaptive behaviour.

 

Evolution is an imperfect process. The only thing that we can be assured of is that on average and in the longer term its latest developments confer benefits to those inheriting them in our particular environmental context.

But if we go back to Koestler’s concern about the tension between passion and reason it is instructive to take a look at the people you know. There will undoubtedly be some outliers. There are those who seem ultra-rational and with little emotion. There will also be those who are ultra-emotional with little rationality. These are the folk who exemplify Koestler’s concern. But take some solace from the fact that they are a small minority in our population. The benefits bestowed on us by the neo-cortex are indeed enhanced when it can play its proper role alongside the brain’s more ancient constituent parts.

Teilhard was certainly right in this regard that our evolutionary progress relies on complexification. Invariably complexification will require resolution of the conflicts and ambiguities it will inevitably create.