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Introduction

The Mystery of Homo Sapiens (continued)
By Alan F. Alford

The Mystery of the Human Brain

The greatest mystery of Homo sapiens is its incredible brain. During the last fifteen years, scientists have used new imaging technologies (such as positron-emission tomography) to discover more about the human brain than ever before. The full extent of the complexity of its billions of cells has thus become more and more apparent. In addition to the brain's physical complexity, its performance knows no bounds - mathematics and art, abstract thought and conceptualisation and, above all, moral conscience and self-awareness.

Whilst many of the human brain's secrets remain shrouded in mystery, enough has been revealed for National Geographic to have boldly described it as 'the most complex object in the known universe'.

Evolutionists see the brain as nothing more than a set of algorithms, but they are forced to admit that it is so complex and unique that there is no chance of reverse engineering the evolutionary process that created it. The eminent scientist Roger Penrose, for example, commented:

    I am a strong believer in the power of natural selection. But I do not see how natural selection, in itself, can evolve algorithms which could have the kind of conscious judgements of the validity of other algorithms that we seem to have.

What does the fossil record tell us about our evolving brain capabilities? The data varies considerably and must be treated with care (since the sample sizes are limited), but the following is a rough guide.

The early hominid Afarensis had around 500cc and Habilis/Australopithecus had around 700cc. Whilst it is by no means certain that one evolved from the other, it is possible to see in these figures the evolutionary effects over two million years of the hominid's new environment.

As we move forward in time to 1.5 million years ago, we find a sudden leap in the cranial capacity of Homo erectus to around 900-1000cc. If we assume, as most anthropologists do, that this was accompanied by an increase in intelligence, it represents a most unlikely macromutation. Alternatively, we might explain this anomaly by viewing erectus as a separate species whose ancestors have not yet been found due to the poor fossil records.

Finally, after surviving 1.2 to 1.3 million years without any apparent change, and having successfully spread out of Africa to China, Australasia and Europe, something extraordinary happened to the Homo erectus hominid. Perhaps due to climatic changes, his population began to dwindle until he eventually died out. And yet, while most Homo erectus were dying, one managed to suddenly transform itself into Homo sapiens , with a vast increase in cranial capacity from 950cc to 1450cc.

Human evolution thus appears like an hourglass, with a narrowing population of Homo erectus leading to possibly one single mutant, whose improved genes emerged into a new era of unprecedented progress. The transformation from failure to success is startling. It is widely accepted that we are the descendants of Homo erectus (who else was there to descend from?) but the sudden changeover defies all known laws of evolution. Hence Stephen Jay Gould's comment about the 'awesome improbability of human evolution'.

Why has Homo sapiens developed intelligence and self-awareness whilst his ape cousins have spent the last 6 million years in evolutionary stagnation? Why has no other creature in the animal kingdom developed an advanced level of intelligence?

The conventional answer is that we stood up, thereby releasing our two arms, and began to use tools. This breakthrough accelerated our learning through a 'feedback' system, which stimulated mental development.

The latest scientific research does confirm that electrochemical processes in the brain can sometimes stimulate the growth of dendrites - the tiny signal receptors which attach to the neurons (nerve cells). Experiments with caged rats have shown greater brain mass developing where the cages are full of toys rather than empty.

But is this answer too simple? The kangaroo, for instance, is extremely dexterous and could have used tools but never did, whilst the animal kingdom is full of species which do use tools but have never become intelligent. Here are some examples. The Egyptian vulture throws stones at ostrich eggs to crack their tough shells. The woodpecker finch in the Galapagos Islands uses twigs or cactus spines in up to five different ways to root out wood-boring insects from rotten trees. The sea otter on the Pacific coast of North America uses a stone as a hammer to dislodge its favourite food, the abalone shellfish, and uses another stone as an anvil to smash open the shellfish.

These are examples of simple tool use, but there is no sign of it leading anywhere. Our nearest relatives, the chimpanzees, also make and use simple tools, but can we really see them evolving intelligence at our level? Why did we acquire a brain which qualifies as 'the most complex object in the known universe', whilst the chimpanzees did not?

Understanding Darwinism

In order to throw down the gauntlet to the evolutionists, it is essential to conduct the fight in their own territory. A basic understanding of state-of-the-art Darwinian thinking is therefore essential.

When Darwin first put forward his theory of evolution by natural selection, he could not possibly have known the mechanism by which it occurred. It was almost one hundred years later, in 1953, that James Watson and Francis Crick discovered that mechanism to be DNA and genetic inheritance. Watson and Crick were the scientists who discovered the double helix structure of the DNA molecule - the chemical which encodes genetic information. Our schoolchildren now understand that every cell in the body contains 23 pairs of chromosomes, onto which are fixed approximately 100,000 genes making up what is known as the human genome. The information contained in these genes is sometimes switched on, to be read, sometimes not, depending on the cell and the tissue (muscle, bone or whatever) which is required to be produced. We also now understand the rules of genetic inheritance, the basic principle of which is that half of the mother's and half of the father's genes are recombined.

How does genetics help us to understand Darwinism? It is now understood that our genes undergo random mutations as they are passed through the generations. Some of these mutations will be bad, some good. Any mutation which gives a survival advantage to the species will by and large, over many many generations, spread through the whole population. This accords with the Darwinian idea of natural selection - a continuous struggle for existence in which those organisms best fitted to their environment are the most likely to survive. By surviving, an organism's genes are more likely, statistically, to be carried into later generations through the process of sexual reproduction.

A common misconception with natural selection is that genes will directly improve in response to their environment, causing optimal adjustments of the organism. It is now accepted that such adaptations are in fact random mutations which happened to suit the environment and thus survived. In the words of Steve Jones:  'we are the products of evolution, a set of successful mistakes'.

How fast is the process of evolution? The experts all agree with Darwin's basic idea that natural selection is a very slow, continuous process. As one of today's great champions of evolution, Richard Dawkins, has put it: 'nobody thinks that evolution has ever been jumpy enough to invent a whole new fundamental body plan in one step'.

Indeed, the experts think that a big evolutionary jump, known as a macromutation, is extremely unlikely to succeed, since it would probably be harmful to the survival of a species which is already well adapted to its environment.

We are thus left with a process of random genetic drift and the cumulative effects of genetic mutations. But even these minor mutations are thought to be generally harmful. Daniel Dennett neatly illustrates the point by drawing an analogy with a game whereby one tries to improve a classic piece of literature by making a single typographical change. Whilst most changes such as omitted commas or mis-spelled words would have negligible effect, those changes which were visible would in nearly all cases damage the original text. It is rare, though not impossible, for random change to improve the text.

The odds are already stacked against genetic improvement but we must add one further factor. A favourable mutation will only take hold if it occurs in small isolated populations. This was the case on the Galapagos Islands, where Charles Darwin carried out much of his research. Elsewhere, favourable mutations will be lost and diluted within a larger population and scientists admit that the process will be a lot slower.

If the evolution of a species is a time-consuming process, then the separation of one species into two different species must be seen as an even longer process. Richard Dawkins compares the genes of different species to rivers of genes which flow through time for millions of years. The source of all these rivers is the genetic code which is identical in all animals, plants and bacteria that have ever been studied. The body of the organism soon dies but, through sexual reproduction, acts as a mechanism which the genes can use to travel through time. Those genes which work well with their fellow-genes, and which best assist the survival of the bodies through which they pass, will prevail over many generations.

But what causes the river, or species, to divide into two branches? To quote Richard Dawkins:

    The details are controversial, but nobody doubts that the most important ingredient is accidental geographical separation.

As unlikely as it may seem, statistically, for a new species to occur, the fact is that there are today approximately 30 million separate species on Earth and it is estimated that a further 3 billion species may have previously existed and died out. One can only believe this in the context of a cataclysmic history of planet Earth - a view which is becoming increasingly common. Today, however, it is impossible to pinpoint a single example of a species which has recently (within the last half a million years) improved by mutation or divided into two species.

With the exception of viruses evolution appears to be an incredibly slow process. Daniel Dennett recently suggested that a time scale of 100,000 years for the emergence of a new animal species would be regarded as 'sudden'. At the other extreme, the humble horseshoe crab has remained virtually unchanged for 200 million years. The consensus is that the normal rate of evolution is somewhere in the middle. The famous biologist Thomas Huxley, for example, stated that:

    Large changes [in species] occur over tens of millions of years, while really major ones [macro changes] take a hundred million years or so.

In the absence of fossil evidence, we are dealing with extremely theoretical matters. Nevertheless, modern science has managed, in a number of cases, to provide feasible explanations of how a step-by-step evolutionary process can produce what appears to be a perfect organ or organism. The most celebrated case is a computer-simulated evolution of the eye by Nilsson and Pelger. Starting with a simple photocell, which was allowed to undergo random mutations, Nilsson and Pelger's computer generated a feasible development to full camera eye, whereby a smooth gradient of change occurred with an improvement at each intermediate step.

This idea of gradiented, or incremental, change is central to the modern view of evolution. The key point is that for a mutation to successfully spread through a population, each step will only be as perfect as it needs to be to give a survival edge. Richard Dawkins uses the example of cheetahs and antelopes to demonstrate how this genetic rivalry works; the cheetah seems perfectly designed to maximise deaths among antelopes, whilst the antelope seems equally well-designed to avoid death by cheetah. The result is two species in equilibrium, where the weakest individuals die but both species survive. This principle was first put forward by Alfred Wallace when he stated that: 'nature never over-endows a species beyond the needs of everyday existence'. It is the same situation as the trees in a dense forest, which have over a very long time maximised their height in competition for the light.

A Brain Teaser for Darwin

The human brain at birth is approximately one quarter of its adult size. The need for a large skull to house the fully grown adult brain causes human babies to have extremely large heads at birth (relative to other primates). Passing the baby's head through the birth canal is therefore the major problem of childbirth and causes acute pain to the mother.

To many biologists, gynaecologists and anatomists, it is a mystery why the female did not evolve a larger birth canal. The answer is simple - engineering. Such a change would have required a radical redesign in bone structure - an impossibility within the limits of a body which is designed for bipedal walking. The birth canal is thus the limiting factor to man's cranial capacity.

If we cast our minds back several hundred thousand years, before hospitals and midwives existed, it is not difficult to imagine that a large number of infants were stillborn or their mothers killed in childbirth. It therefore seems extremely doubtful that natural selection would have favoured a gene for large brain size, with its potential harmful consequences to both mother and child. Simply put, such a gene would not have successfully spread.

It seems much more likely that natural selection would have deselected the large brain and would have stumbled instead upon a better neural networking system or, alternatively, a means to switch skull growth from pre-birth to post-birth. The fact that it did not, and the fact that the wiring of the brain also seems highly efficient in design, strongly indicates two essential evolutionary requirements. First an incredibly long period and secondly a pressing need to develop its optimum potential.

The latter point is particularly crucial for it implies that the evolving hominid had a pressing need to develop a brain with advanced capabilities in such things as art, music and complex mathematics.

Modern evolutionists, however, agree that natural selection should only bestow as much of a new and better physical trend as is needed for survival. The cheetah and antelope which I mentioned earlier are typical of Richard Dawkins' world, where progress comes from a constructive tension between species - a critical balance between survival and extinction. According to this scenario, the genes which make good brains are favoured by natural selection only because they are absolutely critical to the survival of the species.

Richard Dawkins illustrates this point with a story of how the motor car magnate Henry Ford instructed his staff to survey the scrapyards and find out which components of the 'Model T' did not wear out. As a result, the kingpins were re-engineered to a lower standard. According to Dawkins, the same principle applies to evolution by natural selection. It is worth quoting Dawkins in full, for we will turn this argument back against him:

    It is possible for a component of an animal to be too good, and we should expect natural selection to favor a lessening of quality up to, but not beyond, a point of balance with the qualities of the other components of the body.

The importance of this principle can be judged from the fact that the operation of the brain requires no less than 20 per cent of our body energy. Its complexity thus makes it an expensive organ to run.

Here, then, is the evolutionary crunch. As efficient as the brain is, the average human being does not use it to anywhere near its full capacity. How then can Dawkins explain the massive over-engineering of the human brain? What useful survival skills did music and mathematical ability give to our hunter ancestors? Why has the over-engineered brain not been de-selected?

The evolutionists would no doubt argue that the algorithms of the brain did not evolve for music and mathematics, but were 'exapted' from developments for other purposes. No-one, however, can suggest what these other purposes might have been, that would have led to such a highly evolved mental capability. Charles Darwin's partner, Alfred Wallace, clearly recognised the contradiction when he wrote:

    An instrument [the human brain] has been developed in advance of the needs of its possessor.

Elsewhere, Wallace aired his suspicion that another factor - 'some unknown spiritual element' - was needed to account for man's unusual artistic and scientific abilities.

If we go back one million years to a time when man was fighting for survival, how can Richard Dawkins explain how evolution seems to have favoured non-essential abilities in art, music and mathematics? Why did the brain, which must have been at least partly evolved already, not benefit from any types of useful survival skills such as enhanced smell, infra-red vision, improved hearing and so on?

The final nail in the evolutionists' coffin is this: where was the competitor that caused the brain of Homo sapiens to evolve to such an extreme level of size and complexity? What rival caused intellectual ability to be such an essential survival development for our species? Who were we trying to outsmart?

Could inter-species competition be the explanation? In modern times our most significant achievements - space travel and nuclear weapons for example - have come from superpower competition. Did primitive men split into competitive, rival groups? Could Neandertal have been a competitive threat to his fellow Homo sapiens? On the contrary, the evidence suggests that Neandertal and Cro-Magnon co-existed peacefully. Furthermore, early hominids continued to use simple stone tools for millions of years up to about 200,000 years ago; there is no sign of any escalation in tool use caused by an inter-species conflict.

So, in the absence of an intellectual rival that fits the time frame, the orthodox evolutionary scenario for the human brain seems to be fundamentally implausible...

Copyright Notice

'These pages are the copyright of Eridu Books 2004. The images and diagrams are the copyright of Alan Alford or of other photographers, where indicated. Eridu Books welcomes the reproduction and dissemination of these pages, in original, unaltered form, for non-commercial purposes, but permission must be sought for any other usage, other than 'fair dealing' quotations.'

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