Charles Darwin
 
The theory of Evolution as presented by Charles Darwin has
had a great impact on the world today. It has caused many
debates between religious authorities and those from the
scientific community. This theory had prompted individuals
to think about themselves, their origins and it has changed
the way in which they view themselves in the environment.
However, Darwin was not the first person to write on
evolution. There were many others before him such as
Lamarck, Buffon, and Darwin's grandfather Erasmus Darwin.
However, what distinguishes Charles Darwin from the others
is the fact that he collected and provided substantial
proofs and he related various branches of science such as
geology, botany and biology which helped validate his
theories. His theory of natural selection as stated by
Nelson and Jurmain (1991, p.606) in the modern form is that
"the evolutionary factor causes changes in allele
frequencies in populations due to differential net
reproductive success of individuals." His grasp of the
evolutionary process and the clarity of his work makes
Charles Darwin the most popular figure in the scientific
field of Evolution (Francoeur, 1965, p.34). Charles Darwin
(1809-1882) was the fourth child of Dr. Robert Darwin and
grandson of Erasmus Darwin.
 
Much of Charles' childhood was spent collecting insects,
coins and reading various literature on natural history,
travel and poetry. Charles Darwin was not a scholarly
student during his years at Edinburgh Medical College. He
disliked what was taught and found most of the lectures
boring, yet he developed a natural interest in studying
rocks and fossils. He convinced his father that he could
not be a doctor as his father had wished, so instead
Charles Darwin studied Theology at the University of
Cambridge. After his studies he was given the opportunity
to travel on the H.M.S. Beagle as a naturalist. Darwin took
this opportunity and it is this voyage that propelled him
to begin his work on evolution. During his research, Darwin
read several references which greatly influenced his own
writings. Although there were many factors which affected
Darwin's theories this paper will discuss how Darwin was
influenced by the beliefs of William Paley, Erasmus Darwin,
Thomas Malthus and Charles Lyell.
 
Erasmus Darwin (1731-1802) was a well renowned doctor, poet
and philosopher who wrote many books concerning nature.
Among his works Zoonomia, a medical textbook, has received
the most attention. In this work Erasmus Darwin expressed
such ideas as "evolution by natural and sexual selection,
protective adaptation, inheritance of acquired
characteristics, and even the evolution of mankind" almost
fifty years before Charles Darwin (Nelson & Jurmain., 1991,
p.32). Erasmus Darwin had said that all different living
things were produced over millions of years by one original
ancient parent, such that each offspring had a natural
tendency to improve itself (Karp, 1968, p.14). However,
fossil records show that this theory of one original parent
was not probable (Karp, 1968, p.14).
 
His opposition toward any form of organized religion and
his rejection of Christianity was considered to be
superficial and eccentric (Chancellor, 1973, p.21). His
 
tendency to theorize and create wild speculations without
testing his theories caused his reputation as a scientist
to suffer. By the end of the 18th century all discussions
of evolution were suppressed because of the rigid
creationist views held by the Church who persecuted anyone
who challenged their beliefs (Chancellor, 1973, p.41). It
was not until the publication of Charles Darwin's The
Origin of Species that the discussion of evolution was
revived.
 
Being well renowned, Erasmus' work was discussed in his
family circle thus exposing Charles to the work of his
grandfather early on in his life. Moreover, Charles Darwin
having interest in poetry and philosophy 

was naturally inclined to study the work of his
grandfather. Although Erasmus did not solve the problem of
the process of evolution, the reading and exposure of his
work made it easier for Charles Darwin to approach the
topic and see it in a different perspective from Erasmus
(Karp, 1968, p.17).
 
In his early days at Cambridge University, Darwin was
heavily interested in the works of William Paley
(1743-1805) a famous theologist in his time. Paley's works
which include Evidences of Christianity and Principles of
Moral and Political Philosophy were required reading at the
university. However, Darwin was most impressed by Natural
Theology at the time. In this paper Paley examined the
mechanism of the earth, its creatures, the complexity of
their adaptations, their effective use of natural resources
and their successful defence against nature. Paley also
argued the inevitability of a Creator: "Design must have a
designer. That designer must have been a person. That
person is God" (Brent, 1981, p.274). As a student Darwin
admired Paley and agreed with his philosophy. Paley had
said that every species in existence was separately created
by God. According to Paley nothing evolved. However, while
Darwin was conducting research in evolution, he reread
Paley's paper and discovering the flaw in it's logic proved
it to be an important element in Darwin's reassurrance of
the evolutionary process (Brent, 1981, p.306).
 
Darwin disagreed with Paley on how species came to exist.
Darwin argued that God had created species and through
natural selection these species evolved over periods of
time into the species that exist today. In the end Darwin
used the power of the paper against itself in order to
prove his theory of evolution. "Adaptation turned out not
to be the result of some limitlessly benevolent design, but
the very mechanism through which natural selection was
expressed." (Brent, 1981, 

p.304). Darwin's rejection of Paley's ideology gave him a
sense of pride and acted as a catalyst in his work on
evolution. (Eiseley, 1961, p.178)
 
Although Thomas Malthus was not a scientific writer like
Erasmus Darwin and Charles Lyell, he had quite a strong
influence on the intellectuals of his era due to the
popularity and acceptance of his theories on population
growth. One of these intellectuals was Charles Darwin.
 
Thomas Malthus (1766-1834) was an English clergyman and
political economist in the times of Darwin and his primary
contribution to the economic world was the his theory of
population which was published in Essay on the Principles
of Population in 1798.
 
According to Malthus, population tends to increase faster
than the
 
supply of goods available for its needs. Whenever there is
 
relative gain in production over population growth, it
stimulates
 
a higher rate of population increase; on the other hand, if
 
population grows too much faster than production, the
growth is
 
checked by famine, disease, and war. (Funk & Wagnall's New
 
Encylopedia, 1979, p.438)
 
Malthus' theory was seen as being a dismal expression of
the human struggle for survival. This philosopy of survival
of the fittest was used by many to prevent society from
improving living conditions for the poor.
 
For Charles Darwin, this theory provided an answer to the
problem of evolutionary change through the process of
natural selection. Darwin was impressed by Malthus' work
and realized that the population theory could be applied to
all aspects of organic life and provided a solid base in
which natural selection could be studied. Darwin believed
that the theories of biological variation combined with the
struggle for existence explained the biological divergence
found in organic life. Darwin had such strong beliefs 

in Malthus' theory that he used the population theory to
help explain his own theory about natural selection in his
book The Origin of Species (Darwin, 1859, p.13):
 
In the next chapter the Struggle for Existence among all
organic
 
beings throughout the world, which inevitably follows from
the
 
high geometrical ratio of their increase, will be
considered.
 
This is a doctrine of Malthus applied to the whole animal
and
 
vegetable kingdoms.
 
Since Malthus' theory was very popular and well accepted
amongst the scholars of that era, Darwin used it so that
his theory of natural selection would also be understood
and accepted.
 
Darwin had developed his theories before reading the works
of Malthus, however his ideas were reinforced and this gave
him the confidence to continue. Knowing that Malthus was
popular and well received at the time, Darwin considered
him a powerful ally who could assist him in presenting his
theory of natural selection to the scientific world
(Francoeur, 1965, p.53) .
 
The geometric growth of life as expressed by Malthus greatly
 
impressed him and may have turned his thoughts more
intensively
 
upon the struggle for existence. There is evidence in
Darwin's
 
essay of 1842 of his impressed reaction to the mathematical
 
approach of Malthus. He comments almost as a memorandum to
 
himself: "Study Malthus and calculate rates of increase [for
 
various species]." (Eiseley, 1961, p.53)
 
From the admiration and references Darwin gives to Malthus,
it can be concluded that the ideas expressed by Malthus
made him a key figure involved in Darwin's conclusions
about evolution and natural selection.
 
Sir Charles Lyell (1797-1875) was a British geologist born
in Scotland. Although he studied law at the University of
Oxford and was admitted to the bar, he followed a route
that was completely different. He become a world renowned
scientist famous for his studies and works in the field of
geology.
 
Both Charles Lyell and Charles Darwin were devoted
believers of Uniformitarianism which established that "no
forces had been active in the past history of the earth
that are not also working today" (Nelson & Jurmain., 1991,
p.36). The work that brought Charles Lyell acclaim was
Principles of Geology . This was published when Lyell was
virtually unknown as a geologist by his contemporaries
(Chancellor, 1973, p.81).
 
Lyell showed, through the process of uniformitarianism,
that the
 
earth's crust was formed via a series of slow and gradual
changes.
 
Mountains, rivers, valleys, lakes, deserts, and coastlines
were
 
not the sudden result of cataclysms, but rather the result
of
 
purely natural forces, such as erosion by land, water,
frost, ice,
 
and rain.
 
(Nelson & Jurmain., 1991, p.37)
 
This theory was highly debated amongst the geologists of
the time but Lyell's training in law allowed him to
"marshal the facts of an argument, to weigh evidence and to
present it well" (Eiseley, 1961, p.98). Because of the
simplicity of his writing, his book was read by the curious
public as well as professional geologists. Due to the large
amount of exposure of his book, his theories were gradually
accepted by the scientific community and this cleared the
way for Darwin (Brent, 1981, p.353).
 
Being inclined towards geology, more than any other
science, Darwin read the first volume of Principles of
Geology, during his voyage on the H.M.S. Beagle. This was
very important because Darwin observed evidence