Darwin’s big idea
Charles Darwin’s theory of evolution by natural selection is that all organisms (living things) develop from characteristics, or traits, that are inherited from their parents.
Certain traits have survival advantages. Traits with survival advantages enable an organism to cope better in the environment in which it lives.
Darwin’s big idea was that over periods of time, usually very long periods, offspring possessing the traits with survival advantages become more common. Those not possessing traits that give a survival advantage become less common and may even die out. The process by which organisms with survival advantages become more prominent and those without them die out is called the process of natural selection.
Natural selection is not a matter of chance in the sense that those traits which cope best with the environment become more dominant. But the genetic variations that occur within a population, which give rise to survival advantages or disadvantages are called mutations. Darwin said that these mutations are a matter of chance.
Darwin’s theory of natural selection is not a theory in the sense of it being unproven. It has been proven by what science later discovered about genes.
An example of how natural selection works
An example which is often used to demonstrate Darwin’s theory of natural selection and how certain traits can give a survival advantage, is the peppered moth.
These moths could be either lighter or darker in colour.
Originally most of them were lighter in colour because the light colour gave them a survival advantage. The trees at this time were light in colour, so the lighter moths could not be seen by predators as easily as darker coloured moths.
But then nearby factories began burning coal. Soot pollution form the coal burning led the trees to become darker. The lighter coloured moths then became less numerous because they stood out to predators against the darker trees. So the darker moths became more numerous because they now had a survival advantage- they could not be seen by predators against the darker trees than the lighter moths. The changes in the survival advantages of dark moths over lighter ones occurred over a relatively short period of time. But in most cases the processes take thousands or millions of years to develop.
In Darwin’s world there is a slow but constant battle between different traits within the same species. But there is also often a battle for survival between different species. This battle can be quite cruel. It can lead to the extinction of species that are “crowded out” by others with superior survival advantages for the particular environment. This is happening today. Many species are being crowded out by human beings who have proved to have survival advantages superior to all other animals, or at least other mammals, on the planet. And animals favoured by human beings- domesticated animals such as cats, dogs, cattle, sheep and horses- have become far more numerous while wild animals have often declined in numbers.
The most important of scientific discoveries?
In his book on the history of science, John Gribbin says that Charles Darwin’s theory of evolution by natural selection may be the most important scientific discovery ever. Why does Gribbin think this? Certainly other scientific discoveries have had greater practical benefits than Darwin’s theory of evolution by natural selection.
For example, the discovery and manufacture of steam powered engines from 1775 led to the industrial revolution and greatly expanded the capacity of human beings to produce a vast range of goods and services. And the production of anti-biotic medication from 1945 has enabled people to recover from previously life threatening infections, saving millions of lives.
n the other hand, Darwin’s theory of evolution by natural selection did not change the way human beings produced anything and did not save a single life.
But Gribbin says Darwin’s ideas were so important because they changed forever the way large numbers of people thought about the world and the place of human beings in it.
Prior to Darwin the common view, among educated people and uneducated people alike, was that the world, including human beings, had been designed and created by God for a special purpose.
Before Darwin almost everybody believed that human beings had a special role because, they alone, had been created in the image, or likeness, of God.
Is there a conflict between natural selection and religious views?
Darwin’s theory is that all species, including human beings, had a common ancestor and that human beings evolved in the way we did due to chance, just like all of the other animals. We were not a “special creation” of God.
Darwin knew that his ideas would come into conflict with religious beliefs.
Darwin himself had lost faith in God. This was because of the early death of his daughter Annie and because of his research into natural selection. His research demonstrated too much misery and cruelty in the world to believe in a kind and all powerful God. Darwin gave examples of parasites that fed on body of caterpillars slowly killing them and of cats, who liked to torture mice before devouring them.
Darwin also worried that people might struggle to find meaning in a world where their own creation, and the creation of everything around them, resulted mainly from chance. But he argued that human beings should still be happy. He thought that natural selection helped to explain the existence of suffering in the world. And he saw the change produced by natural selection as fascinating, describing it as resulting in “in wonderfully complex and changing circumstances.”
Darwin’s was not the first scientific discovery to challenge religious beliefs.
The idea of Copernicus, and later Galileo, that the Earth revolved around the Sun had also challenged religious beliefs.
Both the Catholic Church and the leaders of then new Protestant religion originally condemned these ideas because they were seen as contrary to descriptions that are given in the Bible which suggested that the Sun moved around the Earth. Eventually however further scientific development meant that the reality of Earth moving around the Sun had to be accepted by the churches. And it was still possible for the churches to claim that, even though the Earth moved around the Sun, God had created the entire universe and had given we human beings a special place within it.
But Darwin’s idea that human beings were really just one among other animals and that we are not some kind of “special creation” by God was different. It is impossible to reconcile this idea the central idea within Judaism, Christianity and Islam that human beings are God’s special creation. Those who hold that the two ideas are inconsistent include both people who believe and people who do not believe in God.
Even today Darwin’s theories are either completely rejected, or are rejected in part, by many religious groups. Christian groups who insist on a strict or literal reading of the Bible totally reject Darwin’s ideas that human beings evolved from other species and had a common ancestor with the apes.
On the other hand, faced with scientific evidence supporting Darwin’s idea, the Catholic Church and other Christian groups have tried to accommodate Darwin’s views into their religious teachings.
For example, Pope John Paul claimed that evolution is “a fundamental church teaching”. But is it really? The Catholic Church still teaches that God created human beings, indeed each individual human being as a “special creation”. This is not a teaching of evolutionary theory at all.
The idea that human beings were created as God’s special creation is a necessary teaching for the Church. It cannot let go of this idea because if human beings just evolved from a common ancestor, along with other animals, without any intervention by God, there would be no obvious reason to believe that we are special in the sense of possessing an immortal soul that lives on after death. And life after death is the big reward that most religions promise in exchange for religious belief.
The idea that evolution through natural selection is the correct explanation for the development all other living things but that God nevertheless intervened in the evolutionary process to specially create human beings has a name. It is called “theistic evolution”.
Critics argue that theistic evolution seeks to reconcile religion with science as far as it can. But ultimately it rejects science when it comes into conflict with religious teachings about God having created human beings. Theistic evolution is a view shared by some Muslims. Other Muslims reject Darwinism altogether, just like some Christian groups.
The three views on how human beings developed
In summary then, there are today three basic views about how human beings developed. They are:
- Human beings were developed in their current form by God (creationism)
- Human beings evolved from less advanced beings through evolution but with God’s help or as a “special creation” (theistic evolution)
- Human beings developed through evolution by chance without God having anything to do with it (Darwinism or naturalistic evolution).
Surveys have shown that in the USA, where fundamentalist Christian groups are quite strong, about 47% of people believe in creationism, 36% believe in theistic evolution and only 12 % believe in naturalistic evolution. About 5% have no opinion.
Can creationism be scientific?
In the USA in the 1990’s a major controversy broke out in some states about what children should be taught in science courses about the origins of life. In 1987 the USA’s Supreme Court decided that creationism could not be taught in US classrooms because it violated the USA’s Constitution which prohibits Governments from establishing of religion or preference of one religion over another.
This led to religious groups demanding that a theory called “intelligent design” also be taught in science courses in schools.
Intelligent design does not challenge the idea that living things evolve in the sense that they change over time or even that living things are related through common ancestors. But intelligent design proposes that certain features of the universe, and of living things, are best explained by the existence of an intelligent cause, not by the unguided, or “chance” processes, involved in natural selection.
In 2005 a US Court decided that intelligent design was not science but was based in creationism. This meant intelligent design could not be taught as science because this would breach the US Constitution’s provisions against the State establishing a religion.
So in the USA courts of law have decided that the creationist view that God intelligently designed human beings, is not science.
The next article
Darwin’s theory had a huge impact on religious belief.
But what are the main arguments that have traditionally been put forward for and against the existence of God? What is the “personal God”? And what are the real reasons why most people continue to believe in God despite the account Darwin gives of how human beings developed? Read the next article in the series to find out.