Charles Darwin (1809-1882): The Theory of Evolution
(excerpts from An Intellectual History of Modern Europe by Marvin Perry (pp. 249-253)
Perhaps the most important scientific advance of the nineteenth century was the theory of evolution formulated by Charles Darwin, an English naturalist. Darwin did for his discipline what Newton had done for physics: he made biology an objective science based on general principles.
During the eighteenth century, almost all people had adhered to the Biblical account of creation contained in the Book of Genesis. God had instantaneously created the universe and the various species of animal and plant life; he had given every river and mountain and each species of animal and plant life a finished and permanent form distinct from every other species. God had designed the birdís wings so it could fly, the fishís eyes so that it could see under water, and the human legs so that people could walk. All this, it was believed had occurred some five thousand years ago.
Gradually, this view was questioned. Already in 1794, Erasmus Darwin, the grandfather of Charles Darwin, had published Zoonomia, or the Laws of Organic Life, which offered evidence that the earth had existed for millions of years before the appearance of people and that animals experienced modifications that they passed on to their offspring. Between 1830 and 1833, Sir Charles Lyell published his three volume Principles of Geology, which showed that the planet had evolved slowly over many ages.
In December 1831, Charles Darwin sailed as a naturalist on the H.M.S. Beagle, which surveyed the shores of South America and some Pacific islands. During the five year expedition, Darwin collected and examined specimens of plant and animal life. He concluded that many animal species had perished, that new species had emerged, and that there were links between extinct and living species.
Influenced by Lyellís achievement, Darwin sought to interpret distant natural occurrences by means of observable processes that were still going on. He could not accept that a fixed number of separate species had been instantaneously created a mere six thousand years ago. In Origin of Species (1859) and Descent of Man (1871), Darwin used empirical evidence to show that the wide variety of animal species was due to a process of development over many millennia, and he supplied a convincing theory that explained how evolution operates.
Darwin adopted the political economist Thomas Malthus' idea that the population reproduces faster than the food supply, causing a struggle for existence. Not all infant organisms grow to adulthood; not all adult organisms live to old age. The principle of natural selection determines which members of the species have a better chance of survival. The offspring of a lion, giraffe or insect are not exact duplications of their parents. A baby lion might have the potential for being slightly faster or stronger than its parents; a baby giraffe night grow up to have a longer neck than its parents; an insect might have a slightly different color. These small variations give the organism a crucial advantage in the struggle for food against natural enemies. The organism favored by nature is more likely to reach maturity, to mate, and to pass on its superior qualities to its offspring, some of which will acquire the advantageous traits to an even greater degree than the parent. Over many generations the favorable characteristic becomes more pronounced and more widespread within the species. Over many millennia, natural selection causes the death of old species and the creation of new ones. Very few of the species that dwelt on earth ten million years ago still survive, and many new ones, including human beings, have emerged. People themselves are products of natural selection, evolving from earlier non-human forms of life.
In The Descent of Man Darwin stated unequivocally:
The main conclusion here arrived at... is that man is descended from some less highly organized form. The grounds upon which this conclusion rests will never be shaken, for the close similarity between man and the lower animals in embryonic development, as well as in innumerable points of structure and constitution... are facts which cannot be disputed....
We must acknowledge that man with all his noble qualities, with sympathy which feels for the most debased, with benevolence which extends not only to other men but to the humblest living creatures, with his God-like intellect which has penetrated into the movements and constitution of the solar system- with all these exalted powers- Man still bears in his bodily frame the indelible stamp of his lowly origin.
Darwinís theory of evolution had revolutionary consequences in areas other than science. Evolution challenged traditional Christian belief. To some, it undermined the infallibility of Scripture and called into question crucial Christian doctrines-- the Fall of Man, Original Sin, Atonement, Redemption, and human uniqueness-- that rested on the history of humanity as presented in the Bible. Natural selection could explain the development of the organic world without reference to any divine design. Indeed, references to Godís design and purpose now seemed superfluous and an obstacle to a scientific understanding of nature.
In time, religious thinkers tried to reconcile evolution with the Christian view that there was a creation and that it had a purpose. These Christian thinkers held that God was the creator and director of the evolutionary process. The Bible, they contended, was a work of spiritual truth; it was never intended to serve as a textbook or as a work of historical scholarship. Many sections had an allegorical meaning and should not be taken literally. Darwinism ultimately helped to end the practice of relying on the Bible as an authority in questions of science, completing a trend initiated by Galileo.
Darwin also contributed to the waning of religious belief and to a growing secular attitude that dismissed or paid scant attention to the Christian view of a universe designed by God and a soul that rises to heaven. The core idea of Christianity, that people were children of God participating in the drama of salvation, rested more than ever on faith rather than reason. The notion that people are sheer accidents of nature, that they dwell in a purposeless and uncaring universe in which death and not God reigns, was shocking. Copernicus had deprived people of the comforting belief that the earth had been placed in the center of the universe just for them. Darwin deprived people of the privilege of being Godís special creation, thereby contributing to the feeling of anxiety that characterizes the twentieth century.
from On Evolution by Stephen Jay Gould:
The Radical Implications of Darwinís Theory of Natural Selection
The theory of natural selectionís radical implications are still not accepted nor understood today even by people who accept the fact of evolution. Why?
It is not because the ideas are too difficult to grasp. The theory of natural selection is based on three ideas that are generally accepted and understood by thinking people:
Therefore, if only some offspring can survive, then, on average, the survivors will be those within the spectrum of random variation that are better adapted to changing local environments.
That much is clear and generally accepted. However, the reason why Darwinism is still not accepted is because the theory of natural selectionís philosophical implications were too radical for Darwinís time. It challenged so many traditional Western preconceptions that we have not made our peace with it to this very day.
Nineteenth century natural theology presented a vision of Godís relationship to his creation which argued that his attributes are manifest in the design of creation. Nature presents evidence of Godís omnipotence and goodness in the admirable design of its organisms and the harmony of earthís ecosystems. According to natural theology, the design of life makes manifest Godís attributes.
Darwinís sense of naturalism is a direct contradiction of natural theology. In his theory, nature is purposeless. Where natural theology insists nature is benevolent and organisms are well designed, Darwin points to organisms that are full of imperfections, such as the panda and its thumb. To Darwin, even good designs do not reflect the skills and creative powers of a benign deity. Just the opposite. How could a benign God countenance the elimination of so many species? Darwin argued that there is no moral meaning to the processes of nature. The only thing happening out there in the natural world is a struggle for survival through reproductive competition. Organisms struggle to reproduce themselves, and thatís it. Good designs and harmonious ecosystems are side consequences unrelated to the fundamental causality at work.
Darwin got the idea for the theory of natural selection from Adam Smithís liberal economic theories. Smith argued that the optimal national economy could be achieved if the government took a strictly laissez faire approach to regulation. The best government is no government. A harmonious economic system is achieved through an unimpeded struggle for profits. Because humans are moral beings, we have never allowed Adam Smithís theories to gain full sway over our policies. To achieve his vision of the best social system would require the elimination of too many people who have struggled but lost in the competition for profits. Nature, however, is not a moral agent. It can dispassionately eliminate species that are unable to compete for the food supply. Darwinís vision of nature was too radical for people to accept. To Darwin, nature is purposeless, amoral, a pure laissez-faire system.
Darwin also did not use the word
Ďevolutioní in his works. This term implied a mechanism of progress which he
could not accept. Darwinís theory of Ďdescent with modificationí is only
concerned with the adaptation of the species to local circumstances. There is
no inherent, predictable, progressive component to the process, just exquisite
adaptations to the local environment. This aspect of the theory ran counter to
the pervasive belief in progress that generated such optimism in the late
nineteenth century. Most nineteenth century political movements (liberalism,
socialism, conservatism) argued that history was progressing towards the
manifestation of social harmony. Darwin argued that natural history progressed
according to random principles.
Darwin also did not publish the theory for twenty years after it had been formulated. He feared that the radical materialism behind his view of evolution would generate such controversy that his career would be ruined. If one accepts Darwinís theories, one might question the concept of a dual world composed of both matter and spirit. Instead the universe could be understood as a material realm in which matter is the true source of all existence. Furthermore, rigorous application of Darwinís theories suggests that there is no inherent spiritual direction to evolution. Spirit itself can be understood as an illusion born of the complex organization of matter in the brain. This matter is so complex that it can think. The mind has developed a concept of itself that became concrete as a notion of God. In a universe whose whole mechanism can be explained mechanically, God is an illusion born of the sub-state of the brain.
There has been a crisis in the humanist tradition after Darwin, a malaise and angst caused by the fact that we do not know why we are here. Darwinís theories do not destroy morality. Human morality, according to Stephen Jay Gould, should be freed from the constraints of science. The world of facts is what it is, and it is important that we know it, but it can never be the source of direct moral knowledge. Ethical values come from a different source than factual knowledge. We must draw the source of our own values, from our intellect, our experience and our compassion for others.
Life has been around on Earth for a billion years. We have only been here for a couple hundred thousand. Nature is persistent, amoral, utterly fascinating, not immoral or moral. The hardest thing for us is to break our parochial arrogance and to realize that our species is just one more contingent species on earth, just one little twig on an enormously fertile bush of life which if you could replant from seed would never grow anything like us again.