This article provides additional comment on general questions that arise in evolutionary biology and also in other articles on this site. See also Nature & nurture
Questions about evolution
From its controversial beginnings, evolutionary theory has continued to tease the mind by provoking further questions, and finding application in disciplines other than biology.
Many people believe its claims are simply untrue; others are unsure how ideas about evolution might impact on religion, culture, ideas of progress and improvement, and where humans are supposed to fit into the evolutionary scheme of things. Can societies evolve in much the same way as organisms and is there such a thing as cultural evolution?
Here are some FAQs:
1. Does evolution have a purpose (teleology)?
2. Does evolution have a direction – is it progressive (orthogenesis)?
3. Why did the universe seemingly become more and more complex over time, originating as an undifferentiated plasma from which emerged . . . first elements, then compounds, then organic molecules and biological systems, and then human consciousness and increasingly integrated, interdependent, and complicated human societies. What has determined the path from undifferentiated plasma to biological matter that has become aware of itself and its own history (complexification)?
4. Do societies evolve in the same way that organisms evolve (social Darwinism, cultural evolution)?
5. Does the apparent pattern, complexity and fine-tuned operation of biological systems suggest an intelligent creator (intelligent design)?
6. Are humans still evolving and, if so, what are the selection pressures – which particular genes are being selected, and how rapid is this process (future human evolution)?
7. Does the mind have limitations – what are the boundaries of thought?
8. What is life?
9. What is it that makes us human?
10. Did the universe and its laws evolve?
Before discussing these questions here is a brief outline of the current theory of evolution:
For most of Western Christian human history it was believed that species were created individually by God: they had not changed from one kind to another – they were immutable.
In spite of this majority-held conviction, the theory of evolution was brewing for a long time. About 2500 years ago the ancient Greeks had speculated about the possibility of organic change – that over long periods of time organisms ‘evolve’. Anaximander from the great Greek trading city of Miletus (c. 610 – c. 546 BCE) on the present-day Turkish coast ‘ . . . attained the conception, in however primitive a form, that living organisms evolve and change, and are adapted to their way of life or would otherwise be weeded out.’ These insights were expressed in more precise terms 50-60 years later by Sicilian philosopher Empedocles (490–430 BCE).
Empedocles is best known for his unification of the world into four fundamental elements (earth, air, fire and water) all interacting through love and strife (attraction and repulsion). He believed that living things evolved from inanimate matter and changed over time by the selection of those that were better adapted to their environment. Only those that were ‘well organised’ would persist. He expressed, more clearly than Anaximander, the possibility of change through variation and selection.
It is easy to forget that, as recently as the early 19th century, there was no theory of evolution. Modern geology had not arrived (the Earth was considered a creation of God only a few thousand years old with fossils placed within geological strata by God himself). Most people were illiterate and there was an almost universal belief in Special Creation. Australia’s greatest ever botanist, Ferdinand Mueller (1825-1896) died near the start of the 20th century believing in the immutability of species and the falsity of Darwin’s theory of evolution.
From at least the time of ancient Greek philosophers, and subsequently within the Christian tradition, there was a perception or image of the world as objects arranged in increasing degrees of importance or value, one above the other like a ladder. At the bottom were rocks and minerals followed by plants and animals and, at the top, was man, the whole edifice surmounted by God. At the foot of the ladder was hard matter, and at the top was pure spirit. This view of everything (or versions of it) is known as The Great Chain of Being (see grand narratives).
During the Renaissance and Enlightenment, scientific and secular ideas found a place in thinking that had previously been controlled by priests and clerics. It did not make sense to give pride of place to some things over others because they were in some way more ‘perfect’ or ‘higher’ in the Great Chain of Being. Organisms were simply different: more or less complex; some better adapted to their environments than others – but not ‘higher’ and ‘lower’ in some cosmic absolute, moral or religious sense.
By Darwin’s day there were various crude speculations about historical organic change (called transformation or transmutation), and although intellectuals and scientists were puzzled by this aspect of nature no-one had come up with a mechanism for this change. It was Darwin and Wallace who provided a compelling explanation of the mechanism that drove this change.
Darwin was aware of the controversial nature of his ideas but was prompted to publish his extensive research when Wallace said that he would print his (Wallace’s) theory.
In his On the Origin of Species published in 1856 Charles Darwin noted that each organism is different from its relatives and that not all individuals survive to reproduce. Those that do survive tend to have characteristics which have aided their survival. That is, they are better adapted to their environment than those that perished. As characteristics are inherited then this process of ‘weeding out’ over generations produces changes in physical form, and this mechanism Darwin called natural selection.
In short, Darwin maintained that in the biological world we have descent with modification as a result of heritable variation and differential reproduction among replicating individuals. This is a mechanical process of fine-tuning using feedback. Natural selection is now the way we account for adaptive (functional, purposive) complexity.
Gold and Silver Chrysanthemum
Daisy native to Japan
Branch tips of a single plant growing in Royal Botanic Gardens Victoria
An example of repeated patterns in nature – but never perfectly identical – the secret of natural selection.
Photo: Roger Spencer 16 Dec. 2010
Since Darwin’s day the theory of descent with modification has been amplified by modern research. Most importantly we now know that the source of inherited characteristics are genes that are located in chromosomes that occur in every cell of every organism’s body in a chemical we call DNA which ‘codes’ for all the characteristics that are manifest in our bodies. We know that sometimes this DNA can ‘mutate’ and that these mutations are subject to the process of natural selection. We now also realise that natural selection is pervasive: it acts on genes, cells, organs, individuals and communities.
The origin of life
The origin of life itself (‘life’ seems to defy consensual definition, but see what is life?) remains one of the greatest mysteries in biology since the confluence of factors that are required to initiate a self-reproducing and adaptive organism are far more complex than was once thought. We still only speculate, cum philosopher Daniel Dennett, that cyclical processes in nature are like ‘do-loops’ in a computer program and once some sorting process becomes incorporated into a system which has metabolic energy utilization, some genetic ability (capacity to build an internal record of the environment that exists outside a permeable membrane), then we have reproduction with adaptive selection as a form of persistence. The mystery remains unsolved.
The Major Transitions in Evolution (1995) is a book on evolutionary biology written by John Maynard Smith and Eörs Szathmáry listing 8 major phases of evolution considered in terms of intergenerational information transference.
1. Replicating molecules to populations of molecules in compartments
2. Independent replicators (~RNA) to Chromosomes
3. RNA as genes and enzymes to DNA as genes and proteins as enzymes
4. Prokaryotes to Eukaryotes
5. Asexual clones to sexual populations
6. Protists to multicellular organisms
7. Solitary individuals to colonies
8. Primate societies to human societies with language enabling memes and sociocultural evolution
Maynard Smith and Szathmáry identified several properties common to these transitions:
1. Smaller entities have often come about together to form larger entities. e.g. Chromosomes, eukaryotes, sex multicellular colonies
2. Smaller entities often become differentiated as part of a larger entity. e.g. DNA & protein, organelles, anisogamy, tissues, castes
3. The smaller entities are often unable to replicate in the absence of the larger entity. e.g. DNA, chromosomes, Organelles, tissues, castes
4. The smaller entities can sometimes disrupt the development of the larger entity, e.g. Meiotic drive (selfish non-Mendelian genes), parthenogenesis, cancers, coup d’état
5. New ways of transmitting information have arisen.e.g. DNA-protein, cell heredity, epigenesis, universal grammar
1. Does evolution have a purpose?
Both scientists and non-scientists speak of biological processes as though they have functions and therefore purpose: we have eyes to see and ears to hear. It certainly seems as if every organ of our bodies, for example, has a purpose. Not just our bodies, but ecosystems and perhaps the biosphere itself. Perhaps there is an overall purpose for all life . . . and inanimate matter . . . or even the universe?
This is not only a question for theology, where it has no doubt existed since the dawn of the human consciousness, but it is also part of today’s biological language and explanation. Referred to as teleology the apparent ‘purpose’ of living things was subjected to critical examination by Aristotle and later incorporated into Christianity as part of the western grand narrative. Darwin was ambivalent about the subject. Teleology is an important aspect of our thinking about living systems and it is therefore the topic of four separate articles under the heading of purpose.
Philosopher Dan Dennett gives us a simplified account of the evolution of purpose as follows:
‘How can a process with no intelligent designer create intelligent designers who can understand how this process occurred?’
The answer is natural selection which is a mindless, uncomprehending and mechanical process of trial and error. It consists of a self-replicating object (organism) that is capable of ‘self-correction’, the ‘correction’ being made as an inherited adjustment in relation to environmental factors such that only those that adjust to the surroundings persist under reproduction. This results in mindless design.
But how can mindless and uncomprehending design become competent and comprehending design?
Much simplified: there is a transition from simple organisms that persist or not (‘survival of the fittest’) to organisms that respond to environmental factors as ‘rewards’ and ‘reinforcement’, to organisms that can test hypotheses internally before enacting them in the world (they do trials offline), to organisms that, as a matter of cultural evolution, can build thinking tools (language, mathematics, calculus etc.) that improve their wellbeing and chances of survival. These are like ‘apps that are downloaded to our neck-tops’. Physical tools like microscopes and telescopes have greatly extended our insight into the nature of the world and, in a similar way, so have our thinking tools. ‘It is difficult to think with a bare brain’ (Dan Dennett) is an expression that conveys the way we use culturally heritable (non-genetic) mental tools to assist our understanding of the world.
2. Does evolution have a direction – is it progressive?
Evolution revolutionised thinking by providing an alternative way of understanding the organic world. Each group of organisms had followed its own path of change depending on its own particular environmental circumstances but in the general scheme of evolution no one organism was privileged over any other and each had passed through the filter of natural selection.
Because mutations are random it is sometimes assumed that evolution itself is random. However, in the sense that natural selection selects the better-adapted organisms this is not a random process, the point being that any ‘direction’ (orthogenesis) is based on adaptations not some future goal. Though there is no fixed destination for evolutionary change present conditions of both both the organism and its environment constrain possible outcomes … it is a path-dependent process.(see teleology in Meaning & purpose) The best ‘solutions’ to environmental problems may be similar no matter what group the animal or plant belongs to, and that is why there is parallel evolution – similar structures in unrelated groups (e.g. succulence in plants growing in dry environments). In this sense evolution is directional, each species is following its own path but there is no overall objective or pre-determined end-point. Having said this directionality must be acknowledged as indicated by the evolution of the eye which has evolved more than 50 times in different evolutionary lines.
Modern evolutionary theory recognises that in biological terms humans are just one of the many branches of the evolutionary tree, they are not its ultimate goal: chimpanzees are not failures on the way to becoming human beings, they are organisms adapted to their environmental circumstances! Selection favours the successful and these are not necessarily organisms with big brains: intelligence is just one of many adaptations favouring survival. Running fast is also a good strategy.
Insofar as cultural evolution is the product of combined human intentions then the future of humanity is neither directionless nor purposeless.
3. How are we to understand the historical increase in complexity of matter, both inorganic and organic ?
Why did the universe seemingly become more and more complex and organised over time, originating as an undifferentiated plasma from which emerged . . . first elements, then compounds, then organic molecules and biological systems, and then the emergence of human consciousness which is biological matter that has become aware of both itself and its history (the universe contemplating itself) – perhaps the most tantalising bio-physical fact of the universe. Is there, as Plato believed, some kind of organising principle responsible for this process?
Our sense of selfhood, of an ‘I’ at the centre of experience remains an enigma. maybe our experience as a whole is simply what we are talking about. Our intuition is to look for a director or controller when we see organized behaviour, something in addition to the processes themselves, like a little man in our heads pulling various levers of perception and cognition. Perhaps the strong sense of self, of an ‘I’ dictating our behaviour is a non-existent second-order illusion – the mind just works the way it does, we do not need an object in the driver’s seat.
Physicists explain the origin of elements and compounds along with the evolution of stars, galaxies and the cosmos as an inevitable consequence of the laws of physics as matter has heated, cooled, disintegrated and recombined following the Big Bang. Perhaps we should ask where the laws of physics came from and why they are as they are – but we would probably not get a coherent answer.
Just as ’purpose’ is present in organisms along a continuum passing from human conscious purpose (teleology) to instinctive behaviour, to the unconscious goal-directed teleonomy of conscious organisms and all living systems, but perhaps crude ‘purpose’ can be seen in inorganic matter as the interplay between entropy and enthalpy. Could this account in some way for the increasing levels of complexity in the inorganic world that eventually gave rise to self-replicating organic molecules and life. Can evolution and mechanistic ‘purpose’ be seen at the molecular as well the organismic mode of material organisation?
The early universe was simple and with low entropy. With the expansion of the universe entropy has increased and increasing entropy facilitates the growth of complexity. Within the life-cycle of the universe we are at present approaching the midpoint at a peak of complexity before matter will likely disappear into black holes leaving empty space or darkness descends in a heat death.
Complexity is not related to high or low entropy but growing entropy. We confuse simplicity with order: as the universe expands it becomes more disorderly.
Biological systems take up the Sun’s energy as low entropy, returning it to the universe as high entropy.
Once replicating molecules appeared a new or emergent set of conditions arose: the constraint of natural selection. Life is both simple and complex depending on perspective. On the one hand biological systems are the most complex and miraculous aggregations of matter that we know. On the other hand we can express the whole of evolution by natural selection in a simple three-step algorithm:
1. Apply random modifications to a set of forms
2. Expose the new forms to selection pressure
3. Surviving forms return to step 1
This, expressed in a highly simplified form, is how we now understand evolution and the vast diversity of the community of life. Evolutionary change does not inevitably result in increasing complexity; adaptation can also produce simplification.
The formation of elements and chemical compounds as plasma cools to become reconfigured in the gravitational, temperature and pressure changes in supernovae according to physical laws.
With the origin of self-replicating molecules a new set of conditions was superimposed on these physical laws – the rules of natural selection. Change in biological systems is clearly functional, the selection of organism traits depends on how well they actually work in the world – so natural selection is about functional adaptive design. This needs to be carefully considered when thinking about other complex systems like galaxies, weather systems, and stock markets.
Consciousness has a soft problem, and a hard problem. The soft problem is to determine the nature of consciousness in terms of the structure and function of processes in the brain. There is every prospect of making headway here. The hard problem is to give a satisfactory account of the actual sensation of awareness (of having an ‘I’) of self and things. For example, we might have a scientifically complete description of the circumstances of the brain that must exist for us to experience the colour red without having any idea of what the actual mental sensation of red is like. For this we may never find a solution.
We can hardly doubt that human society has also become increasingly complex over time – becoming increasingly interdependent over greater distances using increasingly complex technology, transport, communication, economic systems and so on.
There is a general principle here: as systems become increasingly complex there tends to also be an increase in future possibility (choice) and resilience although the integrated parts develop greater interdependence.
4. Do societies evolve?
Social Darwinism, especially popular in the 1870s, applied Darwinian ideas to society and politics. Nature and natural laws, presented as red in tooth and claw, were used to justify the survival of the fittest in the struggle for existence as evolutionary social forces weeded out the weak and ill-adapted. Ideas like this reinforced the competitive instincts of capitalism and were associated with justifications for eugenics and racism, for the superiority of particular nations as demonstrated by their imperialist achievements, to the holocaust and so on. Often an inherent part of such ideas was a strong sense of progress: that out of biologically-ordained social conflict a ‘higher’ or more evolved level of existence would result. At its extreme social Darwinism was used as a justification for inhumane policies and was treated by both biologists and historians as a distortion of Darwin’s ideas.
Because of the negative connotations of the theory of social Darwinism, especially after the atrocities of the Second World War (including the Holocaust the term is generally seen as pejorative, and few people would describe themselves as Social Darwinists after the war. Opponents of evolution theory have often maintained that social Darwinism is a logical entailment of a belief in evolutionary theory, while biologists and historians maintain that it is rather a perversion of Darwin’s ideas. While most scholars recognize the historical link between Darwin’s theory and forms of social Darwinism, they also maintain that social Darwinism is not a necessary consequence of the principles of biological evolution and that using biological evolution as a justification for policies of inequality amounts to committing the naturalistic fallacy.
Of course biological evolution entails: mutation that is mostly non-adaptive; non-inheritance of acquired characteristics; it is the result of genetic inheritance from two parents. Clearly social evolution must have strong differences. This having been said … historians, anthropologists and sociologists can view societal change through evolutionary theory without necessarily assuming approval or disapproval. As with some organisms, some societies have differentiated to become more complex over time. That just like organisms societies may become better adapted to their circumstances but that these circumstances can change requiring new adaptations. The question can be posed as to whether societies have developed in multiple directions or followed a single path to modernity (an explosion of energy capture). Though such questions need unpacking to become coherent, historian Ian Morris would give an unequivocal ‘yes’ to unilinear social development when history is viewed on a long-term scale as farming communities and cities have developed independently, we assume, in different places and there has been a transition from forager, to village society, to agrarian empire to industrialism. ‘On the one hand, there was only one path to modernity; on the other, it was available only to people living in certain places. But on the third hand, once enough people had gone far enough down that path, everyone else was dragged down it too‘.
Cultural evolution (American expression) and social evolution (English expression) can occur because important items of knowledge or memes (e.g. knowledge of the structure of DNA) can be passed on to future generations as a starting point for further development, this is sometimes called Dual Inheritance Theory (DIT) which, like the new and exciting fields of evolutionary psychology, arose in the 1970s and early 1980s, explaining cultural change as the product of two different but interactive processes. We inherit knowledge by social learning, humans being capable of cumulative culture through which we modify the environment (niche construction) that can influences both our genetic and cultural make-up (gene-culture coevolution) DIT can operate very rapidly and is like a supercharged natural selection. This is a like Lamarckian evolution as a kind of ‘inheritance of acquired characteristics’ that have been passed freely between lineages rather that being inherited strictly from parent to child.
Biological and cultural evolution
Historically the physical and mental attributes of humans have arisen as a result of the whole organism interaction with the environment. Until about 10,000 years ago that environment was essentially the natural environment of land, sea, air and water largely unaltered by human activity. At around 10,000 years ago humans started to alter the physical conditions of their physical environment (through technology like tools, ships, and agriculture, settled communities) and social environment (through the use of written languages).
Biological evolution acts by passing on physical characteristics held in genes (but not characteristics that are acquired in the course of a generation like big muscles). Cultural evolution passes on desired characteristics through memes, bits of culturally valuable information and ideas passed on within and between generations: like genes, memes can (replicate) by being passed between people (but unrelated), they can change (mutate), and respond to selection pressure (adapt). Biological evolution is an ‘unconscious’ mode of change, cultural evolution is ‘conscious’ change.
Cultural evolution has changed the physical environment that determines the way that genes are altered. Our nervous systems evolved in relation to a vastly different world.
Planetary communication of memes is now so rapid that the global human community is ‘wired’ in a manner akin to an individual nervous system. Local dangers and changes are quickly transsmitted into the general processing system and a response initiated. Lovelock’s Gaia hypothesis views the planetary ecosystem as self-regulating (acting homeostatically) in this way – up to a point. As ecosystems break down and humans gain in planetary influence they are now vary close to becoming the central nervous system that regulates the planetary environment. This regulation can proceed haphazardly, or by crisis, or it can be planned. Perhapsdetachment fromnature does not matter provided we understand the way nature’s ecosystem operates?
In terms of major aggressive acts like invasions and killing in very general terms it seems that there has been a general expansion of our sphere of altruism from family, to tribe, to organisation, to nation, to world.
The notion of the planet as a global garden, like Eden, seems very apt.
One interesting suggestion for a mechanism of social change is that suggested by Richard Dawkins in The Selfish Gene, especially technological advance through a form of ‘inheritance’ but where the means of inheritance is not the gene but the meme (an important piece of information passed from generation to generation like the way to start fire, build a car, or manipulate genes).
Social learning is clearly different from genetic adaptation in that ‘memes’ are in no way ‘locked in’ but, even so, behavioural traits can alter the social and physical environments in which genetic selection takes place. One example of this would be the genetic selection of traits like efficient starch and digestion in agricultural and dairying communities (Australian Aboriginals are lactose-intolerant). Perhaps the brain has evolved more efficient mechanisms for processing cultural information. Of course, cultural environments can also select traits that are genetically maladaptive or socially undesirable.
Cultural evolution is Lamarckian evolution (the inheritance of information as memes not genes acquired within a lifetime) combined with the anastomosis of lineages (the inheritance of memes acquired by an entire community not just those of the direct parents).
5. Intelligent design
We tend to think of Darwin’s great contribution to science as the theory of natural selection which explained a mechanism for organic change over time and initiating public outcry by the implication that humans could have evolved from ape-like ancestors. But there were two perhaps more fundamental notions that Darwin would not countenance and which undermined the beliefs of his day. The first was his denial that complex design, nature’s signature, demonstrated the presence of a designer with a purpose or plan for all forms of life (see Meaning & purpose). The second was his challenge to the prevailing view that humans were the end-point or crown of God’s Creation, the pre-ordained end-point of the evolutionary process.
Darwin believed that the design in nature was a product of natural selection and did not require the existence of an independent designer or plan (teleology). He also believed that, though humansw ere truly miraculous biological organisms, they were just one branch of the evolutionary tree: they were not privileged in any way. That is, evolution was not guided in some way towards humans as the pinnacle of God’s Creation (orthogenesis and anthropocentrism).
These views were highly controversial even among his peers and in them he parted company with the co-founder of the theory of evolution Alfred Russell Wallace. Darwin was a materialist (he saw no reason to invoke supernatural causes) while Wallace believed in a spiritual domain, a human consciousness that was more than just material causes. Further, Wallace believed that human intelligence far exceeded that needed by our ancestors and therefore could not be explained by natural selection alone.
Intelligence & intelligent design
Wallace was a Creationist who thought that intelligence could only be explained by intelligent design: ‘… the large brain he actually possesses could never have been solely developed by any of those laws of evolution, whose essence is, that they lead to a degree of organization exactly proportionate to the wants of each species, never beyond those wants …’, ‘a superior intelligence has guided the development of man in a definite direction, and for a special purpose’ [Wallace, A.R. 1870. The limits of natural selection as applied to man. Contributions to the Theory of Natural Selection: A Series of Essays ed Wallace A.R. MacMillan, New York p 359 cited in Pinker p. 8993] Wallace wondered how the human capacity for mathematics, science, the capacity for abstract reasoning, even the ability to play chess, had any connection to our forager ancestors.
So how and why did human intelligence evolve and what are its selective advantages?
Cognitive scientist Steven Pinker suggests that Darwin’s insistence on the primacy of natural selection is supported by two hypotheses of cognition.
Firstly, intelligence is an adaptation to a knowledge-using, socially interdependent lifestyle. Intelligence fills a cognitive niche which allows humans to overcome the evolutionary defences of plants and animals through the use of reason (detoxification of poisonous plants in various ways, and to overcome animals by the use of weapons and traps). Humans were now developing strategies, as it were, in real time while animal and plant strategies were still operating in evolutionary time. Humans could ’think ahead’, animals could only behave by reflex or instinct, ’as if’ they could think ahead.
Human reasoning is based on intuitions about objects, forces, paths, places, states, substances, and other peoples’ beliefs and desires. This explains many unusual human traits including our complex toolkit, wide range of habitats and diets, extended childhoods and long lives, hypersociality, complex mating, division into cultures, and language (which multiplies the benefit of knowledge because know-how is useful not only for its practical benefits but as a trade good with others, enhancing the evolution of cooperation).
Secondly, humans possess an ability for metaphorical abstraction that is constantly evidenced in language. Metaphors in language refer again and again to space, force, agency, and causation. Unlearned metaphors of this kind used by children suggest that metaphors are not just figures of speech but manifestations of innate mode of thought that originally evolved for physical problem-solving and social coordination but which could be applied to abstract subject matter.
For the linguist the capacity of the mind to have thoughts that are combinatorial (simple parts combine) and recursive (parts embedded in other parts) has opened up a vast realm of knowledge for communication.
These two hypotheses explain the emergence of abstract cognition without supernatural or exotic evolutionary forces and are in principle testable by analyses of statistical signs of selection in the human genome. They indicate that Darwin had a better grasp of the implications of natural selection than Wallace.
Science does not use supernatural (scientifically untestable) explanations for observed phenomena.
Intelligent design is a variation of the teleological argument for the existence of God.
Variations on the themes of improbability, complexity, and the delicate finely-tuned balance of nature, Earth and the universe are all forms of the argument from design: that something so ordered and finely balanced as planet Earth must be the product of deliberate, intentional design, the designer being God.
Regardless of any religious or other arguments we are confronted with the reality of a universe that, at the time of the Big Bang, consisted of an undifferentiated plasma but in which, over time, matter segregated into the elements of the Periodic Table, and eventually formed organic self-replicating matter. In the form of the human brain this matter has become aware of itself – able to speculate about its own origins and the origin of the universe, and to delve into its laws. The transition from plasma to matter aware of itself is no less miraculous whether the means of its production were the work of a designer or not, and regardless of the anthropomorphism entailed in the selection of the human brain as an object to compare with the original plasma.
Whatever or whoever the cause it is difficult to avoid the fact that there is a trend towards organized adaptive complexity – to complex design. Natural theology in discarding the ‘argument to design’ also rejected, by implication, the ‘argument to complexity’. In the organic world we must admit that as the stars arose from the initial formless plasma a diversity of elements emerged and their compounds. … so on to society.
6. Human evolution today?
Human biological evolution occurred as an adaptation to ancient natural environments. Today’s human environments are mostly artificial or culturally-created environments. Has this altered the way we are changing biologically? And how will this affect our future evolution?
Certainly we are undergoing rapid and seemingly accelerating cultural change as ever new technologies are released and we build cumulatively on the memes of the past. But what about our bodies and minds? Our bodies, along with those of all other living organisms, are the end point of a 3.5 billion-year process of change that started with the replication of simple organisms. Darwin’s theory of natural selection showed how this change was the result of constant interaction between living organisms and their environment. It was a process that preferentially ‘selected’ those organisms that were better adapted to their environments: the better adapted an organism was to its environment, the more likely it was to survive and pass on its genes to a new generation.
Environment of evolutionary adaptiveness
Evolutionary psychology has placed emphasis on the Palaeolithic environment of evolutionary adaptation (EEA) during which 99% of our formative evolutionary history occurred as we lived in small nomadic bands of hunter-gatherers. This, for example, has produced traits that today are maladaptive (Stone Age minds in modern skulls) such as our desire for salt and sugar, our fear of spiders rather than the realistically much more dangerous driving of cars, and our small-group psychology that predisposes us to a mistrust of strangers … and so on. To evolutionary psychology we owe the idea that most of our cognitive capacities have been acquired as adaptations and that we should think of the brain as modular rather than general-purpose, parts of the mind evolving to address particular evolutionary problems in the same way that our bodies are segregated into interconnected but specialised parts like legs and lungs. So to understand the way we are today it will help enormously if we understand the properties of the environments in which our bodies and brains evolved. This view has critics who find this characterisation unnecessarily ‘Palaeocentric’ and restrictive, prefering an expression like ‘adaptively relevant environment’ for a particular trait, or question the need for any special term at all since the idea is a basic part of the evolutionary account anyway: it is simply the environment with the selective pressures that gave rise to a particular trait, whether physical or psychological and regardless of the time when it occurred.(see Zuk (2013))
How well are we currently adapted to our environment?
The human evolutionary environment underwent a drastic change when, with the Neolithic Revolution we adopted agriculture and began to live in settled communities. Put in the simplest terms – at this point in history our environment of evolutionary adaptiveness changed from from ‘wild’ to ‘man-made’, from ‘natural’ to ‘artificial’, from ‘nature’ to ‘culture’. From living in temporary dwellings, gathering plants and hunting animals we began eating domesticated plants and animals and living in larger more population-dense and built environments: it was the first major step on the path to modern city living. Some, like Jared Diamond, believe that it was the reason for a profound schism between humanity and nature. “With agriculture came the gross social and sexual inequality, the disease and despotism that are the curse of our existence”.[Diamond, J. 1987. The Worst Mistake in the History of the Human Race. Discover, May edition.] Others see the matter differently. Do we have pre-agrarian bodies and minds – stone age genes in a space-age environment? Does it matter that when once we were with our animal relatives in the wild and now we live in buildings and cars with artificial climates and we sit in front of computers and assorted electronic gadgetry for hourse every day? For an account of the discussion see see Neolithic Revolution. Writers also make the general points that with the Neolithic Revolution our basic attitude to nature changed from one of ‘respect’ to one of ‘control’. Associated with this is an increasing detachment. Once part of nature we were now separate from it, a view reinforced by the advent of Christianity which reinforced the primacy of humanity in the scheme of things and removed spirituality from nature and placing it in an afterlife. Here we can consider some of the pros and cons of our evolutionary psychology.
Are we now misfits – have we created an evolutionary mismatch?
How well do we fit into our present-day environment of evolutionary adaptedness? What are the selection pressures operating in modern industrial societies and where are they taking our future evolution? They certainly do appear very different from those operating in the Palaeolithic?
Though we cannot assume that we were once perfectly adapted and in sync with our ancestral environment, or that we are no longer evolving, evolving slowly maybe, but not stuck and frozen in the past, there is substantial evidence to suggest that evolution has not prepared us for the 21st century and that culture must address deficiencies that are our evolutionary legacy. Here is some of the downside in our biology:
1.Our craving for salt, sugar and fats which probably relate to our evolutionarty history such as the need for the quick energy present in the sugar of scarce fruits – leading today to obesity, hypertension, heart disease and other physical ailments.
2. An absorption with passive TV viewing because we have are hard-wired to respond to exaggerated social cues like laughter, smiling faces, and attention-grabbing action.
3. Our enormous emotional investment in the inconsequential outcomes of sporting activity
4. Our ancestral fear of dangerous natural objects like snakes and spiders has not been matched by a similar fear of much more dangerous man-made objects like guns and cars? Evolutionary psychology has a major task in taking such theories from the realms of ‘plausible’ to ‘likely’ or preferably ‘scientifically proven’. Cases like this though do illustrate what novelists and playwrights have been telling us for a long time: that humans-evolution is flawed. The array of emotions and drives we have inherited from the past – love, hate, jealousy, anger, fear, and sexual attraction can go awry as it does with crime, they have trade-offs.
5. The psychological drive that stimulates us to reproduce and pass on our genes is the same drive that can lead to rape, sexual harrassment and so on.
6. Much of morality and the law is concerned with the repression of natural desires and emotions.
7. Our demand for meat has, through agriculture and pastoralism, placed an enormous burden on the natural environment.
Can we assume that because our environment of evolutionary adaptiveness has changed so drastically that we are therefore now poorly adapted – we have modern diseases like diabetes, hypertension, and rheumatoid arthritis. Modern medicine has now vastly reduced the high mortality rates that once ‘weeded out’ mal-adapted individuals. Everyone from the mild asthmatic to people with major genetic disorders now live to pass on their genes, if they wish to do so as a result of improved medicine, food production, and sanitation. In Shakespeare’s time only about 35% of babies reached 21; in Darwin’s day it was 50%; nowadays it is over 90%. Indeed it appears inevitable that through this mechanism we are progressively introducing genetic ‘weakness’ into the human race.
Back to the Palaeolithic?
Should be living more like Palaeolithic humans with more ‘natural’ lifestyles and diets that contain more fruit, nuts and cereal and less fats, salt and processed food? Should we be getting back to nature, re-connecting with the natural world and paying more attention to primal needs?
In making such judgments we are not assuming that life ‘then’ was better than ‘now’ or that the way it was then was the way it was ‘meant to be’ or that we were at some time perfectly adapted to our environment, or that there was a period in our cave-living days of blissful harmony when, like noble savages, we lived at peace with our environment and fellow humans. In all probability Palaeolithic humans, like many of us, looked to the past in the belief that this was a better time. Evolution has surely never been ‘finished’ always a constant tussle of trade-offs.
But if we were hunter-gatherers for 99% of our history as Homo sapiens, isn’t this more likely to be a lifestyle to which our bodies and brains are better (but not perfectly) adapted?
There are several ironies here.
Firstly, if this is indeed the case then it would seem that through the effectiveness of our short-term medical expertise that we are increasing the likelihood of our longer-term demise, this is akin to the way that inoculating domestic animals to resist organisms that would normally affect them perpetuates the rist of the spread of those organisms.
Secondly, much of modern medicine is combating infections due to organisms that are themselves evolving and in doing so, overcoming our medical remedies (vaccines, antibiotics and the like) – this is in a sense an arms race with an uncertain outcome: there would always seem to be the chance of a disease arising to which we have no remedy – in which case raw natural selection will return with avengeance.
Apart from this particular scenario, humanity has now entered a new phase of evolution in which through medical technology and genetic engineering we are now writing our own evolutionary future. We are close to the point where we can manipulate our genetic makeup in whatever way we please. Designer children are just a first step along this road.
We are accustomed to the religious idea of life being sacred and sacrosanct. We also at present accept without protest our genetic fate. As genetic knowledge increases it seems likely that acceptance of the ‘genetic lottery’ will diminish.
Tinkering with the DNA at the core of all life is a matter for bioethicists, biotechnology companies and likely to become increasingly a matter of public engagement.
See BBC Television Program Are we still evolving? [reproductive success not mortality]
How fast are we evolving?
Gene frequencies indicate that human evolution has never ben more rapid than in the last 20,000 years, presumably as a result in the huge changes in lifestyles, adjustment to agriculture, new foods, cities and communal disease.
A key example is European lactose-tolerance absent about 20,000 years ago, fairly common at the time of the Romans and now present in over 90% of people.
7. Does the mind have limitations?
What are the things that our brains cannot grasp or encompass?
Part of our puzzlement is the conflict between our belief that it is possible to know and see what reality is truly like, and our realization that reality as we see it is a product of both the observer and the object under scrutiny (see scientific image and manifest image).
From our mindless evolutionary ancestry we have inherited a predisposition towards individual autonomy . . . and a selfish concern for our individual and basic biological needs. The human evolutionary development of reason showed that this is sometimes undesirable and inefficient, so much of our cultural evolution has entailed communal efforts (codes of behaviour of various kinds) to overcome self-centredness, and the downside of biological appetites and intuitions.
More than ever before in history we have become aware that the mind, like the body, evolved to meet the immediate needs of its Palaeolithic ancestry – its formative EEA (environment of evolutionary adaptation). There is no obvious reason why our brains would adapt to answer questions beyond those posed by the necessities of this former human umweldt. Rather than encompassing everything, our minds are simply fit-for-purpose, with all of the limitations that this implies.
Some of these limitations are listed below:
Nothing can travel faster than light so we can never see beyond the edge of the observable universe. General relativity tells us that nothing within a black hole can escape, and quantum physics indicates we can only predict how ‘stuff’ behaves on average. We struggle with concepts like infinity, even in mathematics.
The reason we cannot predict the future – even with the vast computing power that is now available – is simply the complexity of everything. Part of this puzzle relates to chaos theory and the fact that some systems are sensitive to even the tiniest difference in starting conditions, the weather being a famous example.
Foundations of mathematics
For most scientists mathematics provides the sturdy foundations to everything, But mathematics is itself built on unprovable axioms that might, conceivably, change.
We can never know if our experience of the world is exactly the same as that of someone else, a problem that is vastly increased when we contemplate the experiential worlds of other species. What is it like to experience the world, like a bat, using echolocation?
Classical logic and the supply of necessary and sufficient conditions that give us secure knowledge may not be sufficient to describe the world. Like language our understanding of the world might be more a matter of family resenmlance of ideas where things that are true and false are less common than things that are more or less true and more or less false! The world might have more to do with process, change, fuzzy logic, and degree than with stable and static fact.
The possibility that our minds are limited in their scope is suggested by a range of phenomena: we find it difficult if not impossible to conceive of boundaries to space and time and to imagine infinity; we have a mathematical computing power far inferior to that of a mechanical cumputer being capable of retaining relatively few numbers and objects in short-term memory and being capable of only simple multiplication and division in the mind; we cannot account for the first-person experience of consciousness; we find it extremely difficult to reconcile questions of mental free-will and determinism. It has been suggested that the questions of philosophy – especially metaphysics – might mark a boundary of human thought.
How are we to explain what philosophers call qualia, or sentience, the actual quality of sensation, the ‘I’ that experiences images, sensations, thoughts and emotions resulting from the association of 100 billion neurons having a quadrillion connections (how did that evolve?). Not just the consciousness we assume many animals must feel, but self-consciousness. Self-consciousness is our awareness that our experiences are available for higher-order thought, our experience of experience. Hence, conscious experiences have a dual content: while representing the world to us, they also represent themselves to us. A scientist may know everything there is to know about the physical properties of a particular colour without knowing what it is like to ‘experience’ seeing that colour. The executive subjective ‘I’, the focus of brain activity, remains unsatisfactorally accounted for. Perhaps this is a kind of false conundrum, looking for an explanation when none is called for or can be given. Perhaps consciousness is a kind of ‘primitive’ or fundamental property that cannot be further analysed like the fundamental physical properties of space and time or the basic axioms of mathematics. Perhaps consciousness is present in all things to a greater or lesser degree (panpsychism). Maybe it is simply an emergent property of certain kinds of complex system … patterns of information in neural networks. The brain contains about 86 billion neurons and about 100 trillion synapses, impulses travelling at about 2-200 mph, slow compared to the speed of electricity. Its energy is ‘in’ the axons it does not literally pass along it (think of lit gunpowder). Intelligence seems to have much to do with the capacity of our brains to perform logical functions like ‘and’, ‘or’ and ‘not’. Philosophers and scientists are still challenged to find a convincing explanation.
Another way of looking at this problem is as a simple mistake resulting from an error of personification. Because we see around us people who love, hate, and go to the seaside we make the mistaken assumption that there is a little person inside us that also loves, hates and wants to build sandcastles … but there is no little person inside us, we are the loves, hates, and holidaymakers ourselves. There are experiences, yes, but no separate and independent ‘I’ to experience them. We might ponder three things: an experience, the person having the experience, and the content of the experience: could they be one and the same?
Our brains and bodies co-evolved in constant interaction with the external world. We are inclined to speak of the brain and consciousness as though it were independent of these relational factors but this approach is coming under closer scrutiny and being referred to as ‘the naked brain fallacy’.
The ‘self’ is not something in addition to (or controlling) all these processes. ‘Self’ is simply a way of referring to the integrated independence of these processes. Similarly, in human experience there is no independent ‘self’ that is part of our consciousness, there are only mental processes that are part of our integrated autonomy. Our intuition that we have a ‘self’, like another person (a homunculus) observing our mental activity, is an illusion.
8. What is life?
Defining life has proved an intractable problem and of dubious value. Of greater interest is the drawing together of the characteristics that constitute the ‘family resemblance’ of features that we associate with life. One often neglected characteristic is that life manifests agency:
a. Living organisms take in energy from the environment and transform it for growth and reproduction: they exhibit negentropy increasing general disorder but local order (objects that temporarily resist the second law of thermodynamics to create structure, function, and information)
b. The transmission of historical environmental information
c. The operation of self-regulation or homeostasis
d. Replication with variation that is under selection
e. The capacity for growth, reproduction, functional activity, and continual change preceding death.
f. Life is complex and highly organized
g. Organisms respond to external stimuli: more complex forms exhibit learning
h. Organisms grow by consuming, changing biomass, creating new individuals, and eliminating waste products
9. What is it that makes us uniquely human?
See also Human nature
The suite of characteristics we regard as being distinctly human are largely a consequence of the co-evolution of our three major distinguishing characteristics:
- Social cooperation in large numbers that extends beyond our own kin
- The use of language (facilitating trade in free information)
- The capacity to explain, predict, and control, most notably via the use of complex technology
Expressed in other words – only humans use culture as a form of collective learning.
Each of the above skills has a multiplying or synergistic effect on the others, and all are a consequence of our mental capacity – the information processing of our minds as evolved computational systems with specialized modular functionality enabling spontaneous and meaningful behaviour that is both intuitive and learned, combined with the ability to communicate through language, which permits the transmission and accumulation of knowledge which has, historically, been stored in progressively more efficient forms: spoken, written, printed, electronic.
Cognitive scientists have identified more than 100 universal human mental traits.
Other features sometimes listed as being uniquely human:
c. Use of language
d. Use of fire (possibly evolved for cooked foods)
e. Having little body hair
f. Large brains relative to other animals (1200-1400 cc) which requires carrying (muscles), protection (cranium), and high energy use (25% total). More time was needed for hunting food and less muscle to use up energy
g. Bipedal gait producing better vision and freeing the hands for tools but resulting in back problems and narrowing of the hips and birth canal for the large brain. More deaths in childbirth than other primates resulted in premature birth with soft skull. Children were therefore dependent for longer, remaining in the care of parents for longer than other primates, thus favouring social ties and a relatively prolonged period of learning and socialisation
h. Opposable thumbs (thumbs can touch ring and little fingers facilitating the widespread use of tools)
j. A descended larynx, originating c. 350, 000 BP and probably related to speech and language
k. Living beyond reproductive age
l. Our particular mix of universal behavioural characteristics (our human nature)
m. A sense of humour?
n. Creative intelligence that allows us to reflect and communicate to others matters concerning the past, future, abstract notions and our reflections
o. The capacity for reflexive and recursive thought
10. Did the universe and its laws evolve?
Human existence seems infinitely unlikely. If just one of the fundamental physical constants of the universe had been just slightly different then life in this universe would have been impossible. How can we explain the unlikely ‘accident’ of human life? This phenomenon is called the ‘Goldilocks Enigma’ and it is one of the great questions of modern science discussed in a book of the same name published in 2006 by Paul Davies. The laws of physics, boundary conditions, and physical constants all needed to be just right for human life to evolve.
This question begs more fundamental ones ‘Why is there something rather than nothing?’, ‘Why are all the cosmological constants what they are: why are the ‘laws of nature’ what they are and not something else?’ – indeed – ‘Why are there cosmic laws at all?’ Is the ultimate reason for the universe a question of pure chance, probability, necessity, or purpose? The very harmony and elegance of the universe so admired by scientists, the fact that it is amenable to mathematical and rational exploration and that it displays meaningful order gives it a quality of pre-meditation and predeterminism, a hint of purpose. How can that monumental edifice of reason which is science a product of conscious matter in the universe that has become aware of itself and its history, exist reasonlessly? We have proceeded no further than Plato with this puzzle when he proposed that the universe clearly has an ‘organising principle’. The universe is structured into order on so many scales that we may rightly hope for a comprehensible answer to these questions. To what extent, given certain conditions, are particular outcomes inevitable: how do we account for the order in nature? Here are a selection of answers to ponder:
a. God created the universe this way
b. This is simply the way things are – otherwise they would be different!
c. The multiverse (though it cannot be proven, has been predicted in string theory and eternal inflation theory): our universe is one fragment among many universes that exhibit a wide range of physical laws – although this does require metalaws to account for the multiverses
d. The universe evolved by a process of natural selection. Cosmological Natural Selection addresses the existence of complexity and life in the universe. Cosmologists are now seriously considering that the inanimate universe itself may be the product of ‘natural selection’ among multiverses. One appealing aspect of this theorising is the suggestion that the so-called laws of the universe (and time) are not eternal or absolute in a Platonic sense (see Plato in Socrates, Plato, Aristotle) they too have evolved along with the universe and are a product of time: physics, like biology, is ‘path-dependent’.
e. Our minds are the limited adapted product of our human evolution and we are not equipped to grapple with such questions
f. Science is constantly refining its theoretical map of reality but of its nature there can be no end point to this process – we may never know
A major problem here is the infinite regress of explanation: until we accept ‘something’ as beyond question or unchallengable, unexplained laws … like Platonic mathematics, M-theory, multiverses etc. we cannot proceed. Much of physics still places this ‘something’ as outside our universe, that is, transcendental in some Platonic or theistic way. We can perhaps work inside the universe such that the universe is like information – or software – running on a vast processing system or cosmic computer where laws are emergent or intrinsic to it – with maths, laws, information and understanding somehow looped in on themselves rather than being founded on something else.
Evolution is at the heart of biological science and remains a rich source of intellectual challenges. Although the basic science of evolution by natural selection has been resolved and accepted within the scientific community, there are many important related philosophical, scientific, and ethical questions that will demand examination. Topics of special current interest include continuing research into the genome, especially the human genome, the findings of evolutionary psychology, the deciphering of early human migrations across the planet using genetic anthropology and studies of the present-day selection pressures on human evolution and the many questions relating to bioethics as manipulation of our genetics places all kinds of possibilities within our grasp, from designer children to vastly extended lives. We are edging closer to manipulating our own evolution, but what is the best way that this should be done?
Evolutionary theory can find applications in unusual places. Literary Darwinists use evolutionary theory to formulate principles of literary analysis and interpretation. For example, they investigate interactions between universal psychological properties and the forms of cultural imagination. Darwinian literary studies are, in part, a reaction to post-structural and postmodern analysis of the 1970s and 1980s which emphasized the way that language constructs reality. Darwinian literary theory points out that biologically grounded dispositions constrain and inform discourse and takes issue with the social science presumption that it is culture alone which determines human values and behaviors. Indeed, evolutionary biology is a key discipline uniting the hard sciences with the social sciences and humanities.
Religions have their own explanations of the universe and the place of humans within it. The scientific grand narrative does not see any intrinsic meaning or purpose in the universe: these are terms applicable to the human domain. Meaning and purpose are an intrinsic part of human endeavour and we all have all manner of cultural traditions, beliefs, values and norms that give our own lives meaning and purpose. Though we naturally protect the interests of our own species. Although we have mental and other capacities that set us apart from other primates, in an evolutionary sense we are just another branch of the evolutionary tree, we are not the single point to which evolution has been aspiring. Natural selection ensures that organisms are adapted to their environments: this correlation between organism and environment, functional adaptation, gives the impression of a conscious plan or strategy while it is, in fact, simply the result of events that occurred in the past, not the conscious plan of an intelligent Creator.
We can agree with the ancient Greek philosophers that the overall ethical goal of humanity is human flourishing or eudaimonia – the Good life of just people living in just societies. At a crude biological level this equates to the facility to survive and reproduce – but our lives can be much more than that. As we strive to live stimulating and fulfilling lives in secure societies we realise that our flourishing depends on taking care of, not only ourselves, but the natural world as well. Human flourishing or well-being depends on sustainability, the 21st century eudaimonia.
The DNA double helix
A giant replicating molecule encoding genetic instructions
for the development and functioning of all living organisms.
The helical structure was elucidated by
James Watson and Francis Crick in 1953
based on X-ray diffraction images
of Rosalind Franklin and Raymond Gosling
Courtesy Wikimedia Commons
brian0918 Acc. 10 Sept. 2015
Biology Before Darwin
Darwin and Natural Selection
First published on the internet – 1 March 2019