The Great Debate: Modern Theory and the
evolution n. the doctrine according to which higher forms of
life have gradually arisen out of lower Chambers 20th Century Dictionary
Charles Darwin first expounded the idea of natural selection in his 1859
book, Origin of Species. Before Darwin, the idea that evolution had
taken place was becoming widely accepted in the scientific establishment. In
Origin of Species he demonstrated two things; that natural selection provided
the mechanism needed to drive evolution and that sufficient time had passed for
natural selection to have worked. This famous text, along with Darwin's 1871
work The Descent of Man, placed human beings firmly in the animal
kingdom for the first time and permanently altered our vision of ourselves.
Darwin's experience of animal husbandry (in particular breeding pigeons)
and selective plant breeding informed his idea of natural selection. He noted
that bloodlines could be changed fairly quickly through selective breeding and
argued that a similar process could take place in nature whereby the attributes
of individuals who were more successful at reproducing than others would spread
through the population over time. Organisms that were better suited to a
particular environment in any generation would have an advantage that would
ensure that the next generation contained a high percentage of their offspring.
Natural selection, then, is the filter which allows only those organisms
with the best traits to produce offspring successfully. Although chance always
plays a role in deciding the fate of an individual organism, over a number of
generations advantages conferred by particular traits make it more likely that
organisms who have those traits survive for long enough to reproduce. Over time
this leads to organisms which are better adapted to the environment they live
in than their predecessors were.
An adaptation is an evolved trait that contributes to the survival
and reproductive success of an organism, i.e. it is a trait designed by natural
selection. It can be a physical or behavioural characteristic. For example,
eyes, the tendency to fly South in the winter.
The importance of certain adaptations is that they make the organism well
suited to its particular environment - we think of natural selection as honing
adaptations over the course of time. For example, camouflage, the ability to
eat particular foods. This notion lies behind the Darwinian explanation of how
the diversity of life we see today evolved, for the forms of life have expanded
to fill an incredible variety of environmental niches, and of course the
development of new forms of life has expanded the number of such niches. For
example, before animals could evolve there had to be plant life for them to
It should be noted that, while adaptation can be optimal (the more
generations have lived in the same environment the more likely this is to be
the case) it is not always so; there are physical and historical constraints on
what traits can evolve; sufficient genetic variability may not be available;
the intricacies of building a complex organism precludes fundamental changes in
design; there is the 'dead hand of history'. The palaeontologists Stephen Jay
Gould and Niles Eldredge accuse the advocates of gene-centred view such as
Richard Dawkins of imagining that all adaptation is optimal, an approach they
describe as 'the Panglossian paradigm' after Voltaire's famous caricature of
Leibniz, Dr. Pangloss who thought of every calamity as, no doubt, being for the
It is worth making the distinction here between an adaptation and a trait
which is adaptive. An adaptive characteristic is one that increases the
likelihood that the organism who possesses it will survive for long enough to
reproduce successfully. Some argue that, if we take an adaptation to be an
evolved trait designed by natural selection it does not necessarily follow that
it is adaptive; the human appendix can be described as an adaptation but it is
not adaptive since it performs no function in modern humans.
gene n. one of the units of DNA, arranged in linear fashion
on one of the chromosomes, responsible for passing on specific characteristics
from parents to offspring. Chambers 20th Century Dictionary
'A gene is life's way of remembering how to perpetuate itself' Suzuki and
Genes can be conceptualised as chunks of information which code for traits
such as those discussed above. Every cell of most plant and animal life
contains DNA (deoxyribonucleic acid). DNA is made up two strands consisting of
small molecules called nucleotides forming a double helix. There are four types
of nucleotide used in DNA, each of which contains a deoxyribose sugar, a
phosphate, and one of four nitrogen-containing bases: adenine, thymine, guanine
and cytosine usually denoted A, T, G and C. These bases provide the code which
is the basis of life; triplets such as AAG, sometimes described as 'words' are
known to code for amino acids. Amino acids are the building blocks of proteins,
which in turn are the building blocks of living cells.
In discussing genes which code for a particular attribute of an organism it
is always tempting to imagine a simple one-to-one correspondence between a
single strip of DNA and the characteristic in question. In reality things are
nowhere near so straightforward; Usually a gene will actually consist of a
number of three-base 'words' distributed in many locations along the length of
the DNA; Many genes have more than one function and different genes can have
the same function; Genes can be switched on and off at different times in an
organism's life; The environment in which an organism lives can have an
influence on development.
It is worth distinguishing here between the ways that geneticists and
evolutionary biologists use the term 'gene'. For geneticists a gene is a
stretch of DNA which codes for a specific protein, while for evolutionary
biologists, as George Williams defined it, 'a gene is any portion of
chromosomal material that potentially lasts for enough generations to serve as
a unit of natural selection.'
From the point of view of using the term meaningfully we will take a gene to
be something which codes for a recognisable or measurable attribute of an
organism. This is a reasonable definition for the purposes of this discussion
despite the complications outlined above since it is meaningful to talk, for
example, about genes for height in human beings; Even though we know that diet
and other environmental factors have some bearing on the height an individual
grows to, we also know that his or her parents' genes will be highly
The Modern Synthesis
It is worth noting that Darwin did not understand the mechanics of
heredity. Although Gregor Mendel's work which established the rules of heredity
was published in 1865, it was not widely discovered until the beginning of the
twentieth century and was presumably never read by Darwin. This underlines the
strength of the notion of natural selection for, while the new science of
genetics and the discovery of mutation in the early twentieth century were at
first taken to undermine Darwin's ideas, it was only twenty years before
natural selection and genetics were brought together in the modern synthesis
which is still the orthodoxy today.
It is fair to say that, even amongst those who argue vociferously about the
relevance of other factors to the study of evolution, the consensus is that
- genetics provides the mechanics for traits to be inherited and
- natural selection is the mechanism which leads to adaptation and diversity
Social Darwinism comprises a variety of doctrines that emerged at the end of
the nineteenth century. What they have in common is that they attempt to apply
Darwinian theory to human social phenomena. One of the most influential forms
of Social Darwinism made an analogy between nature (for animals) and society
(for humans); they argued that society and the economy constitute a competitive
arena in which only the 'fittest' individuals are successful. They claimed that
much inequality was due to innate differences - the working classes were poor
because they were biologically inferior. Biological determinism, as expressed
by Social Darwinism, provided a convenient scapegoat for the persistence of
social inequality. These ideas, which provided the foundation for racial
thought in the first half of the twentieth century, express the more general
retreat from the Enlightenment ideas of equality and human universalism.
However, after the experience of the Holocaust and World War II these ideas
were discredited, and it is the close association of Social Darwinist thought
with eugenics and Nazism which has made some of the discussion of later
theories so vitriolic.
Sociobiology is a term used to describe the new approach to understanding
animal behaviour using methods derived from game theory which emerged in the
1960s and 70s (see for example John Maynard Smith). This approach was
popularised by Richard Dawkins in his 1976 bestseller The Selfish Gene,
the clever title of which captures well the principles underlying the new
model: the theory provided a link between genes and behaviour.
Niles Eldredge (1995), one of the critics of the selfish gene model,
concedes that sociobiology 'is the outstanding achievement of ultra-Darwinian
biology' but writes that he thinks the attention it has attracted 'is a
reflection . . . of the general cultural infatuation with gene-centred
explanations that has become one of the legacies of the molecular biological
Much of the ambivalence towards this approach has arisen because the
sociobiologists, led by Edward O Wilson (who first introduced the term
sociobiology), also made claims regarding human beings - they attempted to
explain human behaviour in terms of adaptation. They argued that since we are
evolved beings our behaviour must be adaptive - that is, that it must
contribute to whether or not we successfully reproduce. This expansion of
theory into the human realm was regarded with some suspicion - it was seen by
many to be too like Social Darwinism and as such was attacked by some as
racist. For this reason many theorists, notably the evolutionary psychologists,
have been anxious to distance themselves from sociobiology.
Richard Dawkins first introduced the idea of the meme in The
Selfish Gene partly because of his discomfort with the sociobiologists
approach to human behaviour. A meme is a unit of cultural transmission or
imitation. Like the gene, which is a self-replicating molecule, the meme is a
replicator; when a meme is imitated it has replicated itself. Dawkins argues
that human beings are determined largely by social factors, not just by genetic
code and, noting also that social change takes place orders of magnitude faster
than genetic change, there must be some other unit of selection at work; the
Examples of memes are as diverse as the god meme, the idea of evolution,
ways of cooking sausages. Unlike the sociobiologists this allows for a whole
range of behaviours which need not confer any reproductive advantage on the
individual. As Dawkins puts it 'a cultural trait may have evolved in the way it
has, simply because it is advantageous to itself.'
Evolutionary Psychology (EP) is a school of thought which emerged over the
last ten years pioneered by Tooby and Cosmides (of The Adapted Mind
fame) and which has been highly influential on authors such as Matt Ridley and
Geoffrey Miller. The evolutionary psychologists go to great lengths to
distinguish their approach from that of the sociobiologists and it is fair to
say that it does differ. What the two approaches do have in common is that they
attempt to understand the modern human mind in evolutionary terms.
Evolutionary psychologists begin by noting that modern humans (homo sapiens
sapiens) first appeared about 100,000 years ago and that those first human
beings had evolved in the environment of evolutionary adaptedness (EEA), which
is presumed to be the savannas of Africa. Certain assumptions are then made
regarding the way of life of our ancestors of that period; that they lived as
hunter gatherers in small kin-based groups, were nomadic or semi-nomadic, had
stone age technology (at most), short life expectancy and a high infant
mortality rate. Evolutionary psychologists argue that our minds as well as our
bodies should be adapted for this lifestyle. They then attempt to explain
various aspects of human behaviour in terms of evolved tendencies or
predispositions to behave and think in particular ways. To obtain clues they
look to the behaviour of our closest cousins, the great apes, and to
anthropological data related to the way of life of modern hunter gatherers.
Implicit in their work is a search for aspects of human nature which are
universal. Matt Ridley gives some examples; male philandering, females being
impressed by male status.
One aspect of EP thought is the view of the mind as made up of specialised
modules; the metaphor of a Swiss army knife is a popular one for this idea.
Like a Swiss army knife, which has many tools, each designed for a specific
purpose, the mind is considered to consist of many modules, each evolved for an
adaptive purpose. Examples include a language module and a 'theory of mind'
Another model of the mind that has become popular in recent years is that
of the mind as a computer. Ever since the dawn of the digital age claims have
been made about artificial intelligence (AI). The AI movement started its life
in the 1950s. Its aim is to create a computer that can think like a human and
thus to explain how the humans think. The computer thus becomes the model of
the mind. Especially in this age of brain scanning technology, where the path
of a thought can be traced as it moves through the brain, it is indeed tempting
to think of the brain as a computer and of the mind as a function of the brain.
Why then, the proponents of AI argue, should a computer not be able to mimic
the human mind?
It is interesting to note that, following early attempts to produce a
general problem solver, there was a move in the 1970s towards developing Expert
Systems; programs designed for specific types of problem. It is here that we
see the seeds of the modern idea of the modular mind discussed above. In the
1980s neural networks became the next generation of AI methods and represented
an attempt to mimic the architecture of the brain more closely.
Despite claims to the contrary the evidence suggests that we are still a
long way from creating sentient, intelligent artificial minds - if only because
of the enormous computational power that would be required to get anywhere near
the complexity of a human brain.
The question is still open over whether the brain and mind can be considered
the same thing.
It is interesting that Matt Ridley, a strong advocate of evolutionary
psychology, sees free will as an adaptation 'there was a reason that evolution
handed our ancestors the ability to take initiatives and the reason was that
free will and initiative are means to satisfy ambition, to compete with fellow
human beings, to deal with life's emergencies, and so eventually to be in a
better position to reproduce and rear children'.
In contrast Rita Carter thinks that free will and agency are illusions
created by the way natural selection designed our brains. She argues that human
beings must be determined because we are part of the natural universe which is
governed by the laws of cause and effect. On the illusion of free will she says
'The reason it is so utterly convincing is that the illusion - like the
illusion that the objects around us are solid, or have some integral colour -
is deeply wired into the brain as a set of mechanisms which automatically
create the sense of self/subjectivity and agency that makes it feel as though
we decide what our acts will be rather than merely respond to stimuli.' She
cites as evidence that this is the case experiments that show that the brain
begins an action before consciousness of it emerges. She also argues that
neuroscience is now unravelling the mechanism of self and agency and claims
that these are charted well enough for them to be copied in AI systems raising
the question; will these "self-sensing" robots develop the same sense
of agency and subjectivity we have?
Susan Blackmore, in her 1999 book The Meme Machine comes to
remarkably similar conclusions. She makes the case that human beings are
products of both natural and memetic selection; 'We humans are simultaneously
two kinds of thing: meme machines and selves . . . Our bodies and brains have
been designed by natural selection . . . In addition, because of our skill with
language and our memetic environment, we are all repositories of vast numbers
of memes' and argues that the idea of an inner self is a 'selfplex' - a
collection of memes creating the illusion of self -
'I' am the product of all the memes that have successfully got
themselves inside this selfplex - whether because my genes have provided the
sort of brain that is particularly conducive to them, or because they have some
selective advantage over other memes . . .
She goes on to argue that the illusion of self gives rise to a number of
other illusions, including free-will, consciousness and foresight. For her,
even human creativity is best understood as the product of memetic evolution;
'the generative power behind this creativity is the competition between
replicators, not a magical, out-of-nowhere power such as consciousness is often
said to be . . . Replicator power is the only design process we know of that
can do the job, and it does it. We do not need conscious human selves messing
about in there as well.'
C. Badcock, Evolutionary Psychology: A Critical Introduction, Polity
Press, Cambridge, 2000
J. Barkow, L. Cosmides and J. Tooby (eds), The Adapted Mind: Evolutionary
Psychology and the Generation of Culture, OUP, 1992
S. Blackmore, The Meme Machine, 1999
R. Carter, Mapping the Mind, Weidenfeld and Nicolson, 1998
C. R. Darwin, On The Origin of Species by Means of Natural Selection,
John Murray, London, 1859
C. R. Darwin, The Descent of Man and Selection in Relation to Sex,
John Murray, London, 1871
R. Dawkins, The Selfish Gene (new edition), OUP, 1989
D. C. Dennett, Kinds of Minds: Towards an Understanding of
Consciousness, Phoenix, 1997
N. Eldredge, Reinventing Darwin, Weidenfeld and Nicolson, 1995
R. A. Fisher, The Genetical Theory of Natural Selection, Clarendon
Press, Oxford, 1930
T. Honderich, The Oxford Companion to Philosophy, OUP, 1995
J. Huxley, Evolution: The Modern Synthesis,1942
S. Ledger and R. Luckhurst (eds) The Fin de Siècle. A Reader in
Cultural History c. 1880-1900 ed. OUP, 2000
K. Malik, Man, Beast and Zombie, Weidenfeld and Nicolson, 2000
J. Maynard Smith, Evolution and the Theory of Games, CUP, 1982
M. Ridley, The Red Queen: Sex and the Evolution of Human Nature,
Penguin, 1993 (reissued 2000)
D. Suzuki and P. Knudtson, Genethics, Unwin, 1990
E. O. Wilson, Sociobiology, Harvard University Press, 1975
F. Arouet de Voltaire, Candide, 1759
1. What aspects of human nature do you think are the same
now as they were in the EEA? Why?
2. Why do you think some of the reactions to evolutionary psychology are so
heated? Is it justified?
3. What implications do these theories have for free will? Do you think
this influences which theories are popular at the moment?
4. Do you think we have free will? What arguments support your conclusion?
1. What do you think distinguishes human beings from animals? In what ways
do these factors influence the study of human beings?
2. The old dichotomy of nurture vs. nature is no longer accepted by most
modern theorists - everyone agrees that human behaviour can only be understood
as a combination of the two. How should this influence the way we interpret the
theories we have discussed?
3. What aspects of human nature do you think are universal? Can they be
explained in evolutionary terms?
4. Do you think we are determined? What by and in what ways? Does
determinism undermine the possibility of free will?
1. Are there contradictions between the EP and AI views of the mind? What
are they? Are they reconcilable?
2. In what ways do you think a computer differs from a human mind? Could a
computer mimic a human mind?
3. How much influence do you think the current view of humanity has on the
modern theories we have discussed? Is it possible to have an objective science
of human nature?
4. Which approach to the study of the mind do you think tells us most about