Many people, both Christian and Muslim, reject the theory of evolution on religious grounds. Some reject completely the idea that any life forms have evolved. Others accept the theory of evolution with regard to explaining the origin of animals while rejecting the theory as an explanation for the origin of man.
While everyone is in principle free to believe whatever they wish, some religious people also try to prevent children being taught about evolution in schools, or alternatively seek to have their religious views taught as if they were a scientific theory (creationism) meriting parity in the science curriculum with evolution.
Conversely there are many other devout Christians and Muslims who have no difficulty accepting the theory of evolution as an explanation for the origin of all of the life forms that we see today.
There are a number of observational facts regarding the diversity of life forms that we find on planet Earth today that need explanation.
Amongst this diversity we find a great deal of commonality even at the level of organs that could be observed and studied with the tools of 19th-century science. Once we carry out analysis of DNA (Deoxyribonucleic acid) using modern scientific instruments, we find a great deal of overlap in the DNA of the life forms that we see today.
Secondly, we have the fossil record showing that many other types of life form have existed on the planet. The fossil record can be dated. The earliest dating mechanisms looked at steady geological processes such as erosion. We now have much better dating mechanisms which rely upon the rate of decay of radioactive elements. These allow us to estimate how long ago some of the fossils that we find lived.
For thousands of years, humans have actively intervened in the breeding of certain animals such as horses and cows. We did this without any detailed scientific knowledge, simply by selecting animals that had desirable characteristics (such as horses that ran faster) and arranging for them to have superior opportunities for reproduction. Accordingly, when scientists began to grapple with the problem of how species originated, it was natural to consider the inheritance of desirable characteristics and how this might be achieved without the type of intervention that humans have applied to animals.
Originally these scientific theories developed in the absence of any detailed understanding of the chemical or biological mechanisms involved.
Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck (1744 – 1829) known as Lamarck came up with one of the earliest theories. A key element in his theory was the inheritance of acquired characteristics; for example if an animal spends much of its life digging and thereby strengthens certain muscles, its offspring are more likely to inherit those stronger muscles. Over many generations this mechanism could then cause very significant variation in species.
Charles Darwin (1809 – 1882) came up with a more compelling explanation in his book "On the Origin of Species" published in 1859. The essence of Darwin's explanation is that animals experience random variations in the characteristics that they are born with. If a variation makes it less likely that an animal will survive, the variation will be less likely to be inherited by the next generation and will therefore disappear. However if a variation assists the survival of the animal, then the variation is more likely to be inherited by the next generation and will eventually become prevalent within that species. When this process is continued over very long periods of time, species can diverge and change fundamentally.
As mentioned above, at this stage there was no detailed understanding of how such variations might come about or be transmitted to the next generation.
Gregor Johann Mendel (1822 – 1884) was an Augustinian friar in Silesia. In his monastery between 1856 and 1863 Mendel cultivated and tested some 29,000 pea plants. From this work he came up with the idea that inheritable characteristics were transmitted by genes, that genes came in pairs and might be either dominant or recessive. A dominant gene (e.g. for pea plants to be tall) would be expressed in the plant regardless of the nature of the other gene in its pair. However a recessive gene would only be expressed if it was paired with another copy of that same recessive gene.
There was still no way of identifying exactly what a gene might be, but Mendel's theory provided a good explanation of what he observed while breeding peas and what is observed when breeding animals. Charles Darwin appears to have been unaware of Mendel's work but a random variation in genes would provide the mechanism for the variations leading to enhanced survival that lay at the heart of Darwin's theory of evolution.
It was only in the 1950s when Crick and Watson ascertained the structure of DNA that we were finally able to have a detailed understanding of what genes might be and how they can suffer variation by changes in the individual nucleotides in the sequence of the DNA.
The first diagram shows a very short stretch of DNA. It is made up of a series of pairs of chemicals known as bases. The second diagram shows the same stretch of DNA after the simplest kind of mutation has taken place. Just one of the chemical bases has been changed in one place, by swapping thymine for the guanine that was there before. This simplest kind of mutation is known as an SNP (single nucleotide polymorphism) since the structure has been changed by just one nucleotide (base).
Accordingly we have a coherent theory of evolution which goes from detailed mechanisms at the molecular level to explaining how species can develop and differentiate. The overall process of evolution requires no conscious intervention by any party; it merely needs the process of genetic variation that we can explain (because chemical activity and radioactivity can cause changes in the sequence of DNA) and the selection method based upon differential survival which causes some genetic variations to disappear while other genetic variations become widely propagated in subsequent generations.
Interestingly some of the latest research in genetics is partially rehabilitating some of the ideas of Lamarck. We are learning more about the mechanisms that cause some genes to be expressed (by giving rise to the manufacture of proteins) while other genes are not expressed, a subject area known as epigenetics. Indeed in the case of identical twins (who by definition have identical DNA) in one twin a gene may be expressed while in the other twin the gene is not expressed. This appears to be due to the way that other chemicals attach themselves to the DNA in a process known as methylation. This process appears to be affected by the condition of the body; for example stress in a mother can affect the way that genes in an embryo that she is carrying are expressed.
While I have never had any doubts regarding the theory of evolution as a good explanation for the facts relating to current life and the fossil record, a few years ago I decided to read more about it. I highly recommend two books by Richard Dawkins.
"The Selfish Gene" provides an important paradigm shift by explaining that it is not the survival of the individual organism that matters, it is the survival of the specific genes within that organism. Indeed Dawkins gives a perspective whereby animals and humans might be regarded as no more than mechanisms for carrying about genes and for enabling genes to compete with other genes for survival in the form of transmission to the next generation.
"The Blind Watchmaker" provides a detailed explanation of how enormous complexity can develop over long periods of time from very simple mechanisms such as mutation and selection by survival. Even something as apparently complex as the eye can readily be explained as the outcome of this simple process.
As explained in my piece "Why science ignores God", religious explanations are out of scope by definition. The Bible and the Quran do not contain observational data that gives us any more information than we see in the life forms around us today and in the fossil record. Furthermore, there is no way to prove or disprove the statements regarding creation which are set out in the Bible and the Quran.
Accordingly science ignores these texts; that applies regardless of whether the scientist is a religious person or an atheist.
One regularly comes across religious people who are doubters of evolution, both Christians and Muslims, and who assert that the theory of evolution contains many gaps and failings and is wholly inadequate to explain the facts regarding current life and the fossil record.
I have occasionally read some of the writings of such people. It is always based upon a wholly inadequate understanding of evolution, often combined with significant distortion of the factual evidence.
The reality is that there is an overwhelming scientific consensus in favour of evolution while of course debate continues regarding specific issues and points of detail. All scientific theories are strictly contingent, in that they may need to be discarded if new facts are found that the theory cannot explain. However in the case of evolution there are no such fundamentally discordant facts known at present.
The Bible contains a detailed explanation of how God created man. There are in fact two separate explanations in the Book of Genesis. The quotes below are from the New International Version.
Then God said, “Let us make mankind in our image, in our likeness, so that they may rule over the fish in the sea and the birds in the sky, over the livestock and all the wild animals, and over all the creatures that move along the ground.”
So God created mankind in his own image, in the image of God he created them; male and female he created them.
God blessed them and said to them, “Be fruitful and increase in number; fill the earth and subdue it. Rule over the fish in the sea and the birds in the sky and over every living creature that moves on the ground.
Then the Lord God formed a man from the dust of the ground and breathed into his nostrils the breath of life, and the man became a living being.
Now the Lord God had planted a garden in the east, in Eden; and there he put the man he had formed. The Lord God made all kinds of trees grow out of the ground—trees that were pleasing to the eye and good for food. In the middle of the garden were the tree of life and the tree of the knowledge of good and evil.
A river watering the garden flowed from Eden; from there it was separated into four headwaters. The name of the first is the Pishon; it winds through the entire land of Havilah, where there is gold. (The gold of that land is good; aromatic resin and onyx are also there.) The name of the second river is the Gihon; it winds through the entire land of Cush. The name of the third river is the Tigris; it runs along the east side of Ashur. And the fourth river is the Euphrates.
The Lord God took the man and put him in the Garden of Eden to work it and take care of it. And the Lord God commanded the man, “You are free to eat from any tree in the garden; but you must not eat from the tree of the knowledge of good and evil, for when you eat from it you will certainly die.”
The Lord God said, “It is not good for the man to be alone. I will make a helper suitable for him.”
Now the Lord God had formed out of the ground all the wild animals and all the birds in the sky. He brought them to the man to see what he would name them; and whatever the man called each living creature, that was its name. So the man gave names to all the livestock, the birds in the sky and all the wild animals.
But for Adam no suitable helper was found. So the Lord God caused the man to fall into a deep sleep; and while he was sleeping, he took one of the man’s ribs and then closed up the place with flesh. Then the Lord God made a woman from the rib he had taken out of the man, and he brought her to the man.
The man said, “This is now bone of my bones and flesh of my flesh; she shall be called ‘woman,’ for she was taken out of man.”
Unlike the Bible, the Quran does not cover creation in one or two distinct passages. Instead information about creation is given in many different verses. Some of them are copied below, in all cases from the Muhammad Asad translation.
4:1 O MANKIND! Be conscious of your Sustainer, who has created you out of one living entity, and out of it created its mate, and out of the two spread abroad a multitude of men and women. And remain conscious of God, in whose name you demand [your rights] from one another, and of these ties of kinship. Verily, God is ever watchful over you!
6:2-3 He it is who has created you out of clay, and then has decreed a term [for you] - a term known [only] to him. And yet you doubt - although He is God in the heavens and on earth, knowing all that you keep secret as well as all that you do openly, and knowing what you deserve.
15:26-29 AND, INDEED, We have created man out of sounding clay, out of dark slime transmuted - whereas the invisible beings We had created, [long] before that, out of the fire of scorching winds. And lo! Thy Sustainer said unto the angels: "Behold, I am about to create mortal man out of sounding clay, out of dark slime transmuted; and when I have formed him fully and breathed into him of My spirit, fall down before him in prostration!"
21:30 ARE, THEN, they who are bent on denying the truth not aware that the heavens and the earth were [once] one single entity, which We then parted asunder? - and [that] We made out of water every living thing? Will they not, then, [begin to] believe?
23:12-16 NOW, INDEED, We create man out of the essence of clay, and then We cause him to remain as a drop of sperm in [the womb's) firm keeping, and then We create out of the drop of sperm a germ-cell, and then We create out of the germ-cell an embryonic lump, and then We create within the embryonic lump bones, and then We clothe the bones with flesh - and then We bring [all) this into being as a new creation: hallowed, therefore, is God, the best of artisans! And then, behold! after all this, you are destined to die; and then, behold! you shall be raised from the dead on Resurrection Day.
24:45 And it is God who has created all animals out of water; and [He has willed that] among them are such as crawl on their bellies, and such as walk on two legs, and such as walk on four. God creates what He wills: for, verily, God has the power to will anything.
29:19-20 ARE, THEN, they [who deny the truth] not aware of how God creates (life] in the first instance, and then brings it forth anew? This, verily, is easy for God! Say: "Go all over the earth and behold how [wondrously) He has created [man) in the first instance: and thus, too, will God bring into being your second life - for, verily, God has the power to will anything!
30:21-22 And among His wonders is this: He creates for you mates out of your own kind, so that you might incline towards them, and He engenders love and tenderness between you: in this, behold, there are messages indeed for people who think! And among his wonders is the creation of the heavens and the earth, and the diversity of your tongues and colours: for in this, behold, there are messages indeed for all who are possessed of [innate] knowledge!
32:5-9 He governs all that exists, from the celestial space to the earth; and in the end all shall ascend unto Him [for judgment] on a Day the length whereof will be [like] a thousand years of your reckoning. Such is He who knows all that is beyond the reach of a created being's perception, as well as all that can be witnessed by a creature's senses or mind: the Almighty, the Dispenser of Grace, who makes most excellent everything that He creates. Thus, He begins the creation of man out of clay; then He causes him to be begotten out of the essence of a humble fluid; and then He forms him in accordance with what he is meant to be, and breathes into him of His spirit: and [thus, O men,] He endows you with hearing, and sight, and feelings as well as minds: [yet] how seldom are you grateful!
71:17-20 "'And God has caused you to grow out of the earth in [gradual] growth; and thereafter He will return you to it [in death]: and [then] He will bring you forth [from it] in resurrection. "'And God has made the earth a wide expanse for you, so that you might walk thereon on spacious paths.'"
Ultimately that depends upon how one reads them.
If one adopts a very literal reading of the Bible, then one would say that the Earth was created by God in six days consisting of 24 hours each, with man being created from clay and woman then being created from man’s rib. That is not consistent with the theory of evolution. There are many Christians who use this as a reason for rejecting evolution.
The Quranic texts are harder to read literally. For example some of the texts copied above, such as Quran 23:12-16, are clearly addressing the way that human beings are born today, so references to clay in Quran 23:12-16 cannot be intended literally. However there are many Muslims who base their rejection of evolution on the text of the Quran.
One argument often encountered from religious people is that the Bible and Quran came from God. Accordingly if evolution is right then why would He have misled us by giving us texts that were incorrect?
However this argument can be reversed. No religious person can deny that God is responsible for all of the life forms that we see today, and for all of the fossil record. When all of this factual evidence points in the direction of one theory, evolution, one can legitimately ask "Why would God mislead us by surrounding us with all this information?"
There is a different issue where science and religious texts appear to conflict which once caused much controversy.
A literal reading of the Bible and the Quran leads one to believe that the sun moves in the sky, rising and setting, and that the Earth is fixed. Giordano Bruno was burnt at the stake by the Catholic Church for daring to argue that reality was different. Galileo Galilei avoided the death penalty but was forced by the Catholic Church to recant and spent the rest of his life under house imprisonment.
Today no intelligent person, regardless of their religious views, has any doubt that the Earth orbits the sun.
To me it is clear that the observational data from life today, from the fossil record, and also from observing changes in microbes in response to selective environmental pressures such as antibiotics (since microbes have short lives and can go through many generations quickly) all point towards the theory of evolution as a completely satisfactory explanation.
Accordingly, religious texts in the form of the Bible and the Quran must be understood in a manner that is consistent with the world that God has put us in, rather than in a manner that contradicts what we observe. The detailed reading of the texts, and the explanation for that reading, is a matter for each individual to resolve for himself or herself, since each of us is personally accountable to God.
I expect that one day evolution will be as uncontroversial with religious people as is the astronomical issue mentioned above.