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).
Erasmus' 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 defense 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 reassurance 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 Encyclopedia, 1979, p.438)
Malthus' theory was seen as being a dismal expression of the human struggle
for survival. This philosophy 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).
To forge new paths in any area is a difficult task. For Darwin, he presented
ideas which were hard to accept at that point in time. But with the perseverance of
a dedicated scientist, Darwin continued his research and will be remembered for the
theories that he presented.
