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Quest: The Essence of Humanity
By Charles Pasternak
John Wiley & Sons
Copyright © 2003
All right reserved.
We're all of us guinea pigs in the laboratory of God.
Humanity is just work in progress (Tennessee Williams)
Scientists have unravelled the human genome. It is time to
take stock. What really makes us human? Philosophers and
scientists have long argued about it. I believe it is our innate
propensity for quest.
The word is derived from the Latin verb quaerere, to search, to
seek. From it we have query and inquisitiveness on the one hand,
conquest on the other. Together the words describe the qualities
that have made us masters of life on earth: we search for new
horizons, we seek explanations for the phenomena around us, but
we also strive to dominate our fellow creatures.
Yet to search is a fundamental quality of all living organisms: it is
as integral to life as growth and reproduction. Plants search and so
do microbes: we all know that plants have a tendency to grow
towards the light-the sun is their only source of energy-and some
microbes swim towards a source of food. So it is not surprising that
animals, sharing a common ancestor with plants and microbes, also
search: primarily for food and amate, and in the non-aquatic animals
for water and shelter also. As animals have become more highly
developed over the past half billion years, so has their capacity to
search. It has reached its peak in Homo sapiens. Not only do we search
for food and water, for a mate and for shelter, but we also search for no
apparent reason at all: it is curiosity alone, not need, that has led men
to seek the source of the Nile and to unravel the origin of the stars.
Pedants may argue that I am using the word 'search' in two
different senses. Plants and microbes respond to light and food in
an involuntary, preprogrammed, manner: it is simply a question of
being attracted to a source of light or a concentration of nutrients.
Man's search is voluntary and variable. Some of us are curious about
the origin of thunderstorms and earthquakes, others are no more
interested in their causes than in the way an automobile or a
computer works, but might like to find out why the most popular
star of the day has abandoned her boyfriend and what the zodiac
holds in store for them this month; they search the media and surf
the Internet for the answers. You are searching for something-entertainment,
knowledge-at this very moment of holding Quest
in your hand.
Physiologists and biochemists, however, have taught us that
there is little fundamental difference between an involuntary act
like the beating of one's heart and a voluntary one like the raising
of an eyebrow, between an involuntary feeling like fear and a
voluntary one like deciding to read this book: the underlying
mechanisms are virtually the same. I will not go into details at this
stage, except to point out that all life-whether that of a bacterium
or a plant, an animal or a human-depends on chemical reactions
between the fundamental units of matter called molecules.
Two types of molecule are the most important for anything that
is alive: genes, which biochemists also know as DNA, and proteins.
Genes are related to proteins in the way that an architect's blueprint
is related to the building he will construct: it defines its shape and its
size. A gene is a set of instructions for making a protein: it specifies
its size and its shape. What proteins do is to endow matter with life:
with movement and growth, with reproduction and an awareness
of the environment, with the ability to search. It is the proteins
underlying the voluntary and involuntary responses of animals
that are similar. Moreover, we now know that some of the genes
involved in the responses of plants and microbes-their search for
light and food-have been retained in animals and man: in other
words, some of the proteins that enable us to search are structurally
related to proteins possessed by much simpler, and older, forms of life.
If there is a continuity of function, and of the underlying molecules,
from ancient bacteria to fish and to birds and to mammals, what is
it that distinguishes one primate-Homo sapiens-from all other
organisms, and especially from that primate's nearest relatives, Pan
troglodytes ,the common chimpanzee, and Pan paniscus, the bonobo
or pygmy chimpanzee? Could it be something as subtle as a
heightened propensity for quest?
For 150 years, since Darwin's time, anthropologists have tried to
identify the qualities that identify man's unique behaviour, but they
have failed. As each suggested characteristic is sought among non-human
primates, it has been found: the use of simple tools, an
ability to reason, the feeling of misery or joy, consciousness and an
awareness of self, the appreciation of humour, the comprehension
of words and an understanding of language. The quality may be
expressed only to a very minor extent, and merely in one or other
species that has been taught by humans, but it leaves us unable to
pinpoint a defining feature of man. Attempts to do so, by writers
as recent as Kenan Malik (2000)in Man, Beast and Zombie, fail
to convince. They have merely fudged the issue by ascribing
man's uniqueness to some non-genetic behavioural trait, like the
development of 'memes', a subject to which we shall return in the
So, in The Rise and Fall of the Third Chimpanzee, the biologist
Jared Diamond rightly describes man as just another primate, to be
classified in the same genus as the bonobo and the common
chimpanzee: provocatively, he calls that genus Homo rather than
Pan. Desmond Morris had done much the same in his book,
The Naked Ape, 30 years earlier. No single feature, it appears,
characterises Homo sapiens: wisdom (sapientia) is certainly not one.
If no discrete attribute explains the essential difference between
chimpanzee and man, we must look for a number of features-none
of which is unique to man-that in combination have
somehow resulted in his altered behaviour, in his increased ability
for quest. What might those features be?
Hundreds of characteristics distinguish man from chimpanzee.
The most obvious to a casual observer are less body hair, a different
type of face, much shorter arms, an upright gait. To a specialist the
features he focuses on are those connected with his particular
discipline. An anatomist will describe in detail the shape of the jaw
and the pelvis as well as every other bone in the body, a nutritionist
will examine the diet in regard to the consumption of animal as
opposed to vegetable protein, an anthropologist will focus on the
earlier onset of reproductive ability and the shorter life span, a
sociologist will observe the mating behaviour in terms of the
duration of sexual urge and number of partners, a statistician will
note the relative differences in height between male and female and
might comment on the larger breasts of human females and the
longer sexual organ of human males.
We will concentrate on just four features that have accompanied
the evolution of man from other primates. The first is a change in
the spine that makes him walk upright. This increases his view of
the horizon and simultaneously frees his hands: you may be able
to wipe the sweat off your brow and to peel a banana walking
along, but a chimpanzee does so sitting down. The second is a
modification in the relative length of thumb and fingers and in the
muscles that control their movement. We can bend our thumb and
move it past each of our finger tips better than a chimpanzee: our
precision grip allows us to sense the shape of objects and to fashion
these in a superior way. Some of us can learn to play a violin or take
out an appendix; a chimpanzee would perform clumsily at either of
these tasks. The third distinguishing feature is the vocal cord. It lies
within the larynx, through which all primates breathe; the cord is
positioned lower down in humans and made into an intricate voice
box through just two small pieces of cartilage. The result is that we
can produce an enormous diversity of sounds-just listen to the
range of Luciano Pavarotti's voice or the recordings of Maria
Callas-whereas a chimpanzee can merely grunt. Yet we are born
with a primitive vocal cord high up in the larynx, just like an ape.
Babies can only whimper and cry, although like chimpanzees they
are able to breathe and swallow at the same time: adult humans
cannot. So a slight lowering of the vocal cord at around a year or so
of age is all it takes to endow a human with the power of speech. The
fourth attribute relates to the millions of neurons or nerve cells that
are responsible for thought and memory, for the power of reasoning.
They are contained in the region of the brain known as the cortex.
Their function is precisely the same in chimpanzees and humans:
the only difference is that we have three times as many.
I believe that it is the combination of these four attributes that has
enabled man to search more widely-both physically and mentally
-than any other animal. In stressing that it is a combination of
qualities that characterises man, I am doing no more than adapting
to a species the definition of individuality formulated by the
immunologist Peter Medawar: 'One individual differs from all
others not because he has unique endowments but because he has
a unique combination of endowments.' On the other hand, man's
heightened ability to search depends so much on his use of
language that I might have chosen to focus on the attribute of
speech alone. In a beguiling book entitled Grooming, Gossip and
the Evolution of Language, the anthropologist Robin Dunbar has
done just that. He suggests that gossiping among humans is an
extension of grooming among apes and that it is gossip that has
led to the evolution of language and thence to man's complex
behaviour. But while speech undoubtedly contributes to man's
superior ability for quest, it alone does not account for the
emergence of civilisations and the development of culture.
Chattering does not produce the great pyramid of Cheops, neither
does it lead to the Mona Lisa or the theory of relativity. Quest does.
The four anatomical differences between man and chimpanzee
on which I have focused-upright gait, agile hand, sophisticated
vocal cord and greater quantity of cortical neurons-have arisen
gradually over the past 5 million years or so. Their appearance was
pure chance; their retention is due only to the fact that their
owners-successive species of primate-outbred others of their
kind. None represents a sudden and dramatic change of form, any
more than does the evolution of terrestrial animals from fish, or of
birds from reptiles. Each of the four anatomical features is specified
by a number of genes. As yet these have not all been identified,
but it is probable that they belong to families that are similar in
humans and chimpanzees. As we shall see in Chapter 4, the
genes responsible for human characteristics are homologues of
genes specifying comparable functions in other primates: so far as
searching is concerned, it would appear unnecessary to postulate
the existence of 'human' genes in order to define the essential
differences between man and ape.
This conclusion applies to all other functions of humans and
chimpanzees as well, and sits easily with the fact that our genetic
make-up resembles that of a chimpanzee by 95%. But a difference
of 5% might still mean that more than 1000 genes are uniquely
human as opposed to chimpanzee-like, and those who subscribe to
this view continue to search for characteristically human genes. I
do not believe they will find them. My interpretation, which is
shared with many molecular scientists, is different. To us, the '95%
similarity' implies that all the genes of chimpanzees and humans
are on average 95% similar and 5%different:some genes, like that
for the alpha chain of haemoglobin, are identical; other genes, like
that for insulin, are almost identical; yet other genes differ by more
than 5%, but even these belong to the same gene family, specifying
the same function, in humans and chimpanzees. There are no
'human' as opposed to 'chimpanzee' genes at all (Figure 1.1).
To summarise the gist of this book. All living organisms, from
bacteria to plants and to animals, search. In humans, the propensity
for quest is amplified; in other primates, it is constrained. Man
has come to dominate the world and every creature on it; the
chimpanzee is in danger of extinction.
* * *
Quest is divided into four parts. In the first, we consider the genetic
basis of searching. In order to do so, the molecular nature of life has
to be appreciated. There is both unity and diversity. All organisms
are made up of the same kind of molecules, but no two organisms,
even of the same species, are exactly alike: they differ in the fine
structure of their constituent DNA and proteins. As a result, one
shrub grows taller than its neighbour, one amoeba swims faster
than its mate, one pigeon coos louder than its sibling, one human
being is more inquisitive than another. It is such subtleties of
molecular structure that also underlie the emergence of new
species: of us humans from an ancient bacterium, as explained in
I have alluded to the search by plants for the light of the sun and
by microbes for food. Because these are relatively simple systems,
many of the molecules that underlie the search have been defined.
It turns out that several of them, proteins as well as smaller
molecules like vitamins, play a role also in the physiological
processes that underlie searching by higher organisms. As will
become apparent in Chapter 3, vision-which is crucial to an
animal's ability to search-is based on a mechanism that has its
origin in the responses of plants and certain microbes to light.
As aquatic organisms moved on to land 400 million years ago,
the search widened. As mammals began to replace reptiles some
65 million years ago, the search widened yet again. And as the
forerunners of modern man began to evolve from other primates
around 5 million years ago, the ability to search increased even
further: the advantages of the attributes I have identified when
looking for food and water, a possible predator, or a new
environment in which to settle, are clear. The benefits of successful
searching in terms of survival and passing on one's genes-the
concept of the selfish gene-are obvious. Recently discovered
molecules related to human quest are introduced in Chapter 4.
The second part of the book traces the quest of modern man, of
Homo sapiens. It is essentially the story of the last 100,000 years,
analysed in terms of man's unceasing search.
Excerpted from Quest: The Essence of Humanity
by Charles Pasternak
Copyright © 2003 by Charles Pasternak.
Excerpted by permission.
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