The Origin of Man

Invited by the Atheist Society of India (ASI): our lecture tour in India 2005

There are not many amongst the more than about one and half a million species of animals and plants properly identified to this very day the evolution of which is as well-known to science as that of our own one, Homo sapiens. The reasons for this are firstly that by its bones and rather big size it is able to leave rather well-preserved fossils, secondly, that it evolved quite recently, and therefore left comparatively little time to erosion and similar processes to destroy these fossils or bury them in too deep layers, and thirdly, that we and thus our scientific apparatus are more interested in discovering its evolutionary history, simply because we belong to this species ourselves.

Why, then, should a rationalist organisation or periodical be especially keen on learning much about this matter that is known since long to science by many and increasingly many details that may interest mainly specialists? The reason for this is simple: because the understanding of this merely natural and long-term historical process is and continues to be obscured by religious mythology and a heap of ideologies stemming from it.

As the translator (and updater) of the probably most comprehensive and perhaps simply best scientific book on that subject, Robert Foley’s ›Humans before Humanity‹ (German: ›Menschen vor Homo sapiens‹, Sigmaringen 2000), I first had the opportunity of realising the effects of tight religious organisation on the spreading and the mere existence of scientific knowledge of that kind: because of that Cambridge standard work existed already not only the English original version, but also an Italian, a Spanish, Portuguese, Russian, and even a Swedish version – Sweden having just eight millions of inhabitants, and crushed and defeated former Soviet Russia being very poor – but why were there no French and especially German translations, whilst these two nations had some scientific reputation to conserve and could even boast of an exceptionally glorious, though fading, scientific past? The answer was: because their governments and publishing houses after WW II got into the grip of the Catholic Church (and, in my country, also their Lutheran junior partners) more than those of any other major country in the world. That was why, after all, only a comparatively tiny publishing house was willing to publish Foley’s international standard work at all; otherwise the German speaking countries – Germany, Austria, and most of Switzerland – had been cut off from the international level of paleoanthropological knowledge (and such is France still to this very day), at least as far as the educated, but not professional public is concerned.

So, after all, Foley’s book did appear in German language, too, though rather late, and sold very well – but only for two or three months, because then the publishing house by other reasons went bankrupt and was immediately bought by some cover organisation of the Catholic Church, as already nearly all major book publishing houses have been in Germany. And, of course, it never reached the market again.

What is it, besides offending crude and archaic myth belief, that might make the big, i.e. Hitler Concordat churches hostile to the spreading of paleoanthropological knowledge? It is the insight into the entire lack of mysteries and metaphysical aspects in the fundamentally natural process that led from ape to human. That there is but a gradual difference between the mind of ape and human might be known to all educated people since Jane Goodall’s path-breaking research; but how this difference really did evolve still let room to much flimsy speculation and metaphysical distortion that is either intended or fated to keep superstition alive.

Of course, I cannot present here the whole of recent paleoanthropological research; he who wants to know the details inevitably must turn to Foley’s book itself (that happily is available in its original edition). But I want to stress at least some insights that might deserve more attention than they normally get:

1. The depart of human ancestry from the next-related ape-species whose other offspring became today’s chimps and bonobos began not much more than five millions of years ago in the African »rift valley«, i.e. parts of today’s south Ethiopia-Kenya-Tanzania. Persistent drought that made trees rare and forests decline played an important part in that process, favouring apes that could move more easily on the ground than others. The swinging from branch to branch had prepared them for bipedism that began by a way of locomotion we still can observe in some gibbons (who are closely related to proper apes).

2. It was thought for a long time that once the hands were freed for elaborate work by upright walking, the path to intelligence and even culture was free from all obstacles, the well-known result something like inevitable. Great thinkers from Anaxagoras to Engels shared this opinion. But it is not true; much of the evolutionary momentum still remained left to chance. This may be demonstrated by at least two facts:

a.) About 8 millions of years ago, there lived a biped monkey (not ape!) species on an island that later was to become Tuscany, i.e. some part of today’s central Italy. This gibbon-like species, Oreopithecus bambolii, lived long before the first true ape had definitely left the trees and walked on the ground on its two feet. In spite of this seeming »advance«, it became extinct quite quickly after its island became connected with the mainland by geological change and consequently was invaded by big predators that ate all bipedists that »incautiously« had left their trees. As Oreopithecus existed a reasonable time, this obscure outcome should be considered as more than a premature »accident« on the road of evolution.

b.) As soon as the human branch had split off from its simian or, more precisely, pre-chimp origin, its members forming the genus Australopithecus split again into one secondary branch that developed a stronger and stronger chewing gear: jaws, teeth, and especially muscles, the fixation of which was most efficiently positioned at the crista of the skull, just like in recent gorillas (who, keep that in mind, did not yet exist in their present form), thus stopping any evolution of a bigger brain, but giving more and more perfection to chewing and crushing hard-shelled nuts and tough roots, an evolution that meant eternal condemnation to vegetarianism and, by that, the final obstacle to brain increase. This secondary branch, which itself by geographical isolation and other reasons evolved into several species, makes up the subgenus of »megadonts«, meaning »big teeth apes«.

The other secondary branch of Australopithecus remained and became increasingly able to consume a wider range of food and, what is most interesting to us, developed some unprecedented level of intelligence. Being enabled to better social coordination, they competed with their other Australopithecus relatives for food and habitat and finally either ate them or made them starve.

This other secondary branch the only survivors of which we are ourselves is called the genus or, more precisely, subgenus Homo. This subgenus also was split into several species, seven to eight of which are paleontologically known; all of them became extinct except one, the latest or second latest one we all belong to, Homo sapiens (hope we deserve that name). It is more than probable that no other Homo species survives among us by ancestry; our own ancestors very probably ate them all or made them starve, but only exceptionally had sexual intercourse with them, though never successfully, at least not in the long run, just as lions and tigers the skeletons of which also do not show more difference than those of the most closely related Homo (sub)genus species. But how did this Homo genus develop unprecedented intelligence, doing so within a constant evolutionary trend (so-called ESS, meaning »evolutionary stable strategy«)?

The direct anatomical means of that trend was something like a slight neotenia; for the proportions of a chimp or bonobo infant, especially its head-body ratio, are far more similar to those of a human adult than to a chimp adult. This will roughly mean that its head is bigger and thus might contain more brain. But brain (or any other neuronal tissue) is more »expensive« than any other body tissue; its carrier needs more high-caloric food than another of the same weight. So, parallel to this slight neotenia, Homo and especially Homo sapiens left gorilla-like vegetarianism. You might say – cum grano salis – that the decisive part of the Homo sapiens evolution started as an anti-Jainist movement. Even in very recent times it could be observed that the brains of Pueblo Red Indians – meaning North American Red Indians living on a higher cultural, i.e. agricultural level than their other North American relatives – constantly had a lower brain weight than those on the lowest cultural level, but feeding mainly on salmon and deer, whilst the Pueblo agriculturalists mainly fed on corn and other vegetable stuff. Also European Cro-Magnon humans at least had a slightly bigger skull than their modern descendants, though, of course, we cannot get their exact brain weight. But apart from their unknown intelligence level that surely was at least not lower than ours, their skeletons reveal their normally admirable health status. They lived on nearly the same diet as the said Northwest American Red Indians of (nearly) our times.

Anyway, the question remains: why did the Homo genus and especially the Homo sapiens species evolve their intelligence? For this costly evolution does not, as is often thought, straightforwardly lead to interspecific competition superiority. In that case it were less rare. In fact, quite often a decrease of lifespan, a shrinking of neuronal and other equipment as in many insects or mice will increase the biological success, i.e. the percentage a species will obtain of the whole of bio-mass on Earth or the lineage of an individual of the whole of the individuals of its species. To say it in Sigmund Freud’s words: »(…) the intention that man should be ›happy‹ is not included in the plan of ›Creation‹«[1] (SE XXI 76). Or, to say it in the language of the wisest but least successful religions as Mandaism and Manichaeism: the world is rather Satan’s than God’s creation. Free-thinkers will appreciate that realistic metaphor which challenges human science and technology to fight »Satan’s« heritage, but churches and any major religions – except perhaps Buddhism – will not. Also this insight will explain some part of religious hostility to science, especially biological science.

Now let us apply biological science to our question again. Animals living on islands or being big are less menaced by predators than others; consequently, they need to spend less of their potential to escape them, but being freed of that necessity they inevitably will invest that potential left to their disposal in competing with each other of their species, i.e. in infraspecific competition. A great amount of this competitive energy will end up in sexual activity that diminishes the chances of competitors; that is why island bird species have the most elaborate mating rituals of any birds, island reptiles the highest copulation activity of all reptiles, and big mammals, especially carnivores, just both of that. When their social coherence gives them an even greater protection against predators, these tendencies will increase – their lifespan being extended (because of infraspecific competition – we observe the same tendency in insular organisms of any kind), their progeny less, but better protected (for the same reason), their infraspecific competition increased on any level.

Exactly that happened in humans of any species. Increase of intelligence (and therefore complexity) was one means of that process; costly as it was, only a big and social species could »afford« it. But why is intelligence (of which tool using and tool making is just a side effect gaining its power only on a very late and cultural level) a means of mere infraspecific competition, including even sexual competition?

To cut a long story short: intelligence gives great advantages in individually cooperating with other individuals of the same sex in struggles for a higher rank; these cooperations are regularly observed in ape societies. They are the key to language’s coming into existence, because language will largely contribute to their efficiency. But high rank will dramatically increase the sexual attractivity of its bearers, especially males’ attractivity to females; we might observe this phenomenon even today in human societies. Any mechanism that by some trait arouses sexual attractivity and therefore increases the chance of spreading it directly, such as long feather tails in peacocks or lyre-birds, provided this trait has a hereditary base (i.e. genes), will rapidly evolve in a dramatic fashion. Exactly that happened to the human brain and its capacity, because by the social means just described intelligence leads by far more than mere strength to high rank in the group and consequently to the widest access of males to females. The results of that dramatic process are we ourselves.

But this was not the aim of evolution, simply because evolution has no aim. If the Homo branch had not been split off from the basic Australopithecus branch that in some respect – the chewing apparatus – had been more evolved than the Homo branch, intelligence evolution in spite of all socio-sexual mechanisms had been stopped by simple but compulsive ecological reasons connected with tool-less nut cracking. And the whole other Australopithecus genus might well have gone a similar way as Oreopithecus already did, becoming extinct before ever reaching self-consciousness that gained us the proud title of sapiens.

So we got our marvellous brain without any intrinsic aim or god by bare good luck. This brain can think free or in bondage, rationally as well as foolishly, boldly as well as cowardly. Let us use it to become safer and happier than we are by nature.