The quest to isolate the defining characteristic of our essential humanity has been a long and convoluted one. Aristotle wrote that “Man is a social animal.” In retrospect this seems far off the mark. Although the human animal is indeed social this is hardly a defining characteristic. We are aware of not only the social tendencies of many other animal species, such as chimpanzees or even wolves, but we now understand that the world of many insects is also decidedly social. The social proclivities of ants, termites and bees are well known. Indeed the social insects have much better organized and much more stable social structures than humans.

Another philosopher of antiquity, St Thomas Aquinas, postulated that “Man differs from irrational creatures in this, that he is master of his actions.” But I would argue that with respect to human behaviour our choices are minimal being largely determined by our biological history and our socialisation. Therefore this characterisation of the nature of humanity is also erroneous.

In Shadows of Forgotten Ancestors, Carl Sagan and Ann Druyan related the beliefs of many other people who tried to enunciate the peculiarly human characteristics. For example the philosopher John Dewey proposed that what distinguishes us is memory. But there is much evidence to suggest that other animals have significant memory capacity. Various philosophers have suggested human identifying characteristics such as our reproductive posture, our long childhood, our beliefs about personal hygiene, our tendency towards monogamy and so on. But none of these features are peculiarly human. And I suppose we would be disappointed if this was all there was to separate ourselves from other animal species.

In the end, the defining characteristic of our humanity would seem to be the nature of our consciousness. Out of this capacity for consciousness has arisen the inevitable idea of individuality and personal identity. It has driven our need for a sense of meaning and purpose which is reflected in our spirituality. It has created a personal “inner” world which each of us has to come to terms with while living in a shared “outer” world. Hence, if self-consciousness is the defining human characteristic, it is worth taking a look at how it may have evolved.

We can look back in wonder at the physical phenomena called the “Big Bang” which seems to have been the precursor of our universe. This event prised matter and existence out of the void. In the beginning the physical universe comprised the simplest of all material elements – hydrogen. Then through fusion as the hydrogen gas was drawn together by the force of gravity creating the stars, more complex atoms were formed. In the stellar night stars formed, disintegrated and were extinguished. From the detritus of these transformations the earth was formed, comprising a multitude of substances, aggregating the materials from predecessor bodies that had formed and were subsequently dissipated by the passage of time and eons of decay. Finally, in a miracle of what the French Jesuit, Teilhard De Chardin called “complexification”, in defiance of entropy, life was created on earth. Who knows what alchemy was involved to tease life out of the physical elements of the primordial soup that covered the earth’s surface? From an intermediary of self-replicating molecules a spark was added that allowed carbon based molecules to reproduce themselves and begin the adventure of evolution that has culminated in a human brain of such complexity that it allowed a gate to open for the entry of consciousness.

We are all the products of this evolutionary process. We are in fact, as Darryl Reanney once observed, made of star-dust. Every element which constitutes part of us that is more complex than hydrogen was formed in the fusion processes of stars. The carbon in our tissues, the calcium in our bones, and the iron in our blood all came to be through this process. Our physical bodies are created from the products of the nuclear reactions stimulated by the condensation of hydrogen through the force of gravity in the nuclei of stars.

The fifteen billion years of creation emanating from the “big bang” have seen the evolution of the universe progress with the “complexification” of matter, its embellishment with the spark of life and finally its crowning achievement – the opening to consciousness. (I deliberately state it this way because I don’t believe consciousness is a product of our brain. I believe consciousness always existed. The evolutionary process that created us merely enabled us to access it once more. But I guess that should be the subject of another blog!)

How did evolution progress from the first spark of life to the production of human beings? First of course there were the single cell life forms, then amoeba and invertebrates of growing complexity through to vertebrates and the branch of the great apes that became hominids and finally Humankind. Genetically we remain very close to those animals that were our predecessors. Yet we are so different. In those eons of time that cultivated the development of the species that was to become homo sapiens something of huge significance finally occurred. Physically we can see that one of the defining characteristics of the transformation of the species is the rapid growth in the forebrain, the temporal lobes. Almost in a cancerous way, the old brain components we share with other animals were capped with the cerebral cortex. This hugely powerful addition to brain structure comes in two relatively similar hemispheres connected by the corpus callosum. It seems to be this, in mechanical terms that have enabled the emergence of that which defines our unique humanity and separates us from all the other sentient, but non-self-conscious life.

Yet it would be erroneous to believe the unique features of human cognition were related to merely brain size. The human brain is neither the largest among animals (those of elephants are four times larger while the sperm whale’s is six times human size), nor is it even the largest in comparison to body size. Many monkeys have brains that are double the size of humans in proportion to their body size. However it is only Humankind that has conjured the technology to venture into outer space, only Humankind that has unravelled the human genome, only Humankind that proposed the theory of relativity. The extraordinary capacity of the human mind is therefore not related to the size of the human brain but to its complexity. This phenomenon is aptly demonstrated by observing a foetus. At its earliest stages of development it has a relatively huge head (and brain). That big head wanes proportionately as the child grows older. But on average, as the child grows older, it also grows wiser. Thus it can be demonstrated that relative brain size is no determinant of intelligence and less so of wisdom.

Yet despite this, the increase in brain size in evolutionary recent times is phenomenal. Anthony Smith in The Mind wrote, “The speed of the swelling [of the human brain] was considerable. From about five hundred cubic centimetres – and therefore comparable in size to gorilla brains – it leaped to the human size of fourteen hundred cubic centimetres in about three million years. Assuming the brain cells of earliest man to be as compressed as in a modern brain this means that some nine billion cells were added during those years or approximately one hundred and fifty thousand per generation.”

This prodigious increase in the size of the human brain left Nature with a design problem. Our distant animal predecessors were tree dwellers. As they learnt to move out of the trees and onto the plains and walk upright the wide ape-like pelvis of the Australopithocines gave way to smaller, more graceful hips and consequently a smaller birth canal. However, at the same time, brain size (and consequently head size) was increasing dramatically. This was an obvious dilemma for childbirth, rendering it more hazardous for both mother and child. The solution that evolution provided changed the whole direction of our species. The issue was resolved by allowing considerable brain growth to occur after birth. This resulted in a shortening of the gestation period and enabled the birth of a child whose head could be accommodated by the narrower birth canal.

The flip-side to this of course is the fact that human children are far more vulnerable than those of other species and must be nurtured and protected longer whilst their brain and physical capacities develop. The rate of growth of the brain is kept to a minimum in the last months of pregnancy. After birth, however, it increases three fold in size in the first year. This long period of maturation provides a fertile opportunity for social enculturation. Consequently, this enables the “learnt” behaviour of humans to be a significant part of their psychological makeup. And this provides a platform for Humankind to evolve through cultural processes as well as biological processes.

Our more remote ancestors were xenophobic and tribal. With the evolution of consciousness came the first sparks of spirituality. We suddenly became aware of time and the fact that we had a past. As well we learnt that our physical being also had a limited future that was terminated by death. It was inevitable that we should start asking questions about the meaning of all this.

The first religions were largely based on fear, guilt, power, and retaliation and how to reconcile ourselves to the awesome powers of nature. The original cities thrown together and reliant on these beliefs (eg Ur, Babylon, Thebes and Machu Picchu) arose only to disappear.

There arose an understanding that collective survival relied not only on the prime biological imperative of “survival of the fittest” based on individual strength and ferocity but increasingly by transcending self-interest in the service of others. This became to be reflected in our religious beliefs. In her magnificent book The Great Transformation, Karen Armstrong defined the period 900-200BCE the Axial Age. She wrote, “The Axial Age pushed forward the frontiers of human consciousness and discovered a transcendent dimension in the core of their being, but they did not necessarily regard this as supernatural …… If the Buddha or Confucius had been asked whether he believed in God, he probably would have winced slightly and explained – with great courtesy – that this was not an appropriate question.”

The emerging religions became more interested in love and compassion which in themselves promoted more robust societies. Instead of conceptualising gods like the Greek and Aztec deities who, like reptiles, devoured their young, the culturally evolved fifth-century BCE humans conceived of models like Socrates, the Buddha and later Christ, who epitomised unselfish love. The disparate xenophobic tribes of their ancestors were now replaced by great societies and empires. Cultural evolution provided a social “glue”, binding human collectives in a way that the world had not previously experienced.

In Spiritual Evolution George E Vaillant wrote,
“Cultural evolution, mediated by language, has been as important for human survival as brain complexity mediated by genetic evolution has been for mammalian survival. Cultural evolution after all, is faster and more flexible than genetic evolution. With effective cultural communication, knowledge accumulated over a lifetime, no longer had to die with the individual. Knowledge started to expand, and thus, analogous to compound interest, the store of human knowledge began to increase exponentially. The capacity for cultural development gave modern humans a tremendous advantage over the Neanderthal. It was if the hardware of the human brain now permitted the addition of software.”

So in recent millennia, human progress has been propelled by cultural evolution. Biological change in Humankind in the same period has been infinitesimal. For the first time in human history “Nurture” surpassed “Nature” as an evolutionary mechanism. Furthermore some are of the opinion that Humankind can deliberately guide this process in what is called “Conscious Evolution.” However, suffice is to say that cultural evolution has resulted in a movement in Humankind from individual survival to concern for the collective. It is built on the platform that Karen Armstrong identified as arising in the Axial Age, that other people matter.