…in this article, I will summarise the key elements of the modern science of evolution, and the reasons why the evidence in its favour is generally regarded among scientists as conclusive, before turning to my main theme, which is the extent to which Muslim scholars anticipated key aspects of the modern theory.
We are grateful to Paul S. Braterman for writing this article for the Muslim Heritage website. Images have been added by the Muslim Heritage team. This article includes extensive content relating to the contribution of scholars from Muslim Civilisation to science; especially zoology, a subject of importance and much interest.
Figure 1: Paul S. Braterman (Source)
We know what comes next, and they don’t. Bear that in mind whenever you see scholars commenting on the significance, in the context of today’s science, of thinkers who died centuries ago. To do them justice, we need to see the world through their eyes, not ours. But we too are people of our own time, and if we are looking for the origins of the concepts that concern us today, we would do well to start off by clarifying those concepts.
And so, in this article, I will summarise the key elements of the modern science of evolution, and the reasons why the evidence in its favour is generally regarded among scientists as conclusive, before turning to my main theme, which is the extent to which Muslim scholars anticipated key aspects of the modern theory. But remember that the aim is to understand their thinking in the context of their own time, rather than in the light of later knowledge.
I conclude that they made important contributions, and that one scholar (al Jahiz) even made the crucial step of realising that one species can evolve into another, and that what are now distinct species share a common ancestor. However, this is still a long way from recognising that such change is universal, or that even highly dissimilar species share a common ancestor, or that these facts are significant.
Figure 2: Illustrations from Kitab Al Hayawan (Book of Animals, Ninth Century Basra) by African Arab comparative naturalist Abu Uthman al-Jahiz (Source)
What is evolution?
The present day science of evolution, considerably more advanced than the theory put forward by Darwin and Wallace over 150 years ago, contains the following essential elements:
1) The Earth is ancient; otherwise, there would not have been time for evolution to have taken place
2) New variations continually arise within species, as a result of imperfect copying of DNA, the genetic material. These changes are called mutations
3) Some variants come to predominate, and sufficient variations lead to the formation of new species. Variations that increase fitness are more likely to be passed on, and those that reduce fitness are more likely to be bred out. This is what is called natural selection.
Natural selection was central to evolutionary thinking for decades. However, the current view is that most variations are neutral, leading to a kind of random drift among possibilities.
Figure 3: Page from the Book of Animals by al-Jahiz (Source)
4) Evolution is constrained by history. We have an extremely rich fossil record, showing how each group of living things has emerged by modification of its ancestors. In this way we can understand built-in design faults such as the tortuous paths of nerves and arteries, the persistence of vestigial features, including DNA that in some species has lost its function, and the widespread occurrence of exaptation, where an organ can be traced back to a precursor with a different function.
Evolution is not “Darwinism”
Figure 3: Reading Darwin in Arabic, 1860-1950 by Marwa Elshakry(Source)
This is all a bit different from what Darwin proposed over 150 years ago. Darwin had no idea of how new variants could arise, since he did not understand the principles of genetic inheritance, and the chemistry of his time was nowhere near ready to understand the storage of information at the molecular level, as happens in DNA. Darwin’s family relationships were based on anatomical resemblance, and he could not even have imagined how these would be confirmed and refined by molecular level comparisons.
Moreover, Darwin saw evolution as driven by natural selection, whereas we now think that neutral drift is at least as important. Finally, Darwin complained about the incompleteness of the fossil record, and his complaints are quoted to this day by anti-evolutionists. However, we now have an enormously rich fossil record, showing, for example, multiple stages in the evolution of land vertebrates from lobefish, mammals from reptiles, whales from hoofed land animals, and humans from their common ancestor with chimpanzees. (Notice that I did not say “humans from chimpanzees”. Humans and present-day chimpanzees are cousins, and you are not descended from your cousins, although you and your cousins are descended from the same grandparents.)
Today, only two groups of people use the term “Darwinism”. On the one hand, we have historians of science who are referring, correctly, to an earlier phase of evolution science. On the other, we have evolution deniers, who want to trivialize that science by associating it with a single individual and reviving objections long since refuted.
The evidence for evolution
How good is the evidence for evolution? Overwhelming. A brief summary can be found at “29+ Evidences for Macroevolution”. Evidence comes from family relationships, the fossil record, anatomical homologies (e.g. the common structural features of the human hand, a whale’s flipper skeleton, and a bat’s wing), vestigial organs, the distribution of living things through space and time, actual observations of evolution in progress, the development within the past three decades of family trees based on molecular biology, and the fact that these family trees correspond in great detail to those already inferred in other ways. I should mention that there is also a cottage industry of anti-evolutionists devoted to raising objections, and that an exhaustive (and exhausting) index of these objections and their refutations can be found on the talkorigins.org website.
How compatible is evolution science with Islam?
Figure 4: Charles Darwin’s “The Origin Of Species” in Arabic (Source)
It is not my place to discuss this. I will merely point out that debate between those who accept and those who reject evolution can be found within all the Abrahamic religions, with discussion hingeing on the ways in which the ancient sacred text should be interpreted by a modern reader (Marwa Elshakry, of Columbia University History Department gives a scholarly account). There are those who protect traditional interpretations by rejecting evolution, but such rejection carries a high cost since it creates a conflict between faith and worldly knowledge. And there are those who attempt to evade this conflict by denying the plain scientific facts; here the cost is even higher. There was a recent vigorous discussion of these topics organized by the Deen Institute, and the scientific academies of Bangladesh, Egypt, Indonesia, Morocco, Pakistan, Palestine, Turkey and Uzbekistan have joined others worldwide in affirming evolution.
Evolution, fixism, and the argument from design
The alternative to evolution is fixism, the belief that the existing forms of life came into existence independently of each other. This immediately raises the question of how they come to be so well adapted to their environments, and the traditional explanation is that this is the result of design. As recently as 200 years ago, it was perfectly respectable for William Paley to argue that the intricacy of organisms pointed to a designer, in his famous analogy with a watch, whose existence implied the existence of a watchmaker. Paley’s lifetime saw the harnessing of Newtonian physics to mechanical invention, hence his choice of example. But very much the same thought had been expressed some 700 years earlier by al-Ghazali, who spoke of “the marvellous formation of animals and plants”, whose “well-adapted arrangement” points to “a maker who governs and adapts it.”
There was nothing hostile to the science of its day in such reasoning. Indeed, Darwin himself was much impressed by Paley before coming to reject him, as he explains in his autobiography
The old argument of design in nature, as given by Paley, which formerly seemed to me so conclusive, fails, now that the law of natural selection has been discovered. We can no longer argue that, for instance, the beautiful hinge of a bivalve shell must have been made by an intelligent being, like the hinge of a door by man. There seems to be no more design in the variability of organic beings and in the action of natural selection, than in the course which the wind blows. Everything in nature is the result of fixed laws.”
But remember that Darwin also wrote there:
Another source of conviction in the existence of God, connected with the reason and not with the feelings, impresses me as having much more weight. This follows from the extreme difficulty or rather impossibility of conceiving this immense and wonderful universe, including man with his capacity of looking far backwards and far into futurity, as the result of blind chance or necessity. When thus reflecting I feel compelled to look to a First Cause having an intelligent mind in some degree analogous to that of man; and I deserve to be called a Theist.”
al-Ghazali, I believe, would have approved. The “old argument” from the design of individual organisms is bypassed by modern knowledge, but the more general argument from the overall design of creation retains its power.
Figure 5: Kalila wa-Dimna (Panchatantra) an ancient Indian collection of interrelated animal fables in verse and prose, arranged within a frame story (Source)
Overview of problem
After this long preamble, we can proceed to our main theme, the extent to which the ideas lying behind the modern science of evolution were anticipated by Islamic World scholars. Here we need to content with two different kinds of distortion. There is, or was until recently, a deplorable tendency in mainstream Western discussions of the history of ideas to downplay the enormous Islamic World contribution, and regard it merely as a pathway by which ancient learning re-entered late mediaeval Europe; I have criticised this arrogant and insular view elsewhere. But there is also the opposite tendency, an understandable but unhistorical boosterism which sees far more in these classical writings than is in fact there. It also must be said that a great deal of the boosterist literature is of low quality, relying on unexamined third hand accounts. There is clearly room here for careful scholarship by someone who is familiar with both the content and history of the relevant science, and the classical Islamic literature in question, but such people must be very hard to find. The most I can do, therefore, is to bring my knowledge of the science to bear, while referring back at each step to the most reliable translations I was able to find of the original texts.
Figure 6: The Crocodile from The Book of Animals by al-Jahiz (Source)
al-Biruni [973 – 1048], Ibn Sina [~980 – 1037], and the age of the Earth
Aristotle had both supporters and detractors among Islamic scholars, but all were powerfully influenced by his ideas. One of these was that the Earth was infinitely old, a belief clearly incompatible with the idea of creation, as it occurs in all the Abrahamic religions. But if it is not infinitely old, how old is it?
The Genesis account of creation would if taken at face value imply a young Earth, with a current age of some 6,000 years, in direct conflict with geological studies that implied an age first in many millions, and now in billions, of years. Both Christian and Jewish scholars have for many centuries rejected such narrow literalism. For example, in the 12th C CE Maimonides sought compromise with Aristotle by suggesting that the Days of Genesis reflected indefinitely long periods of time. But this does not qualify as a scientific argument, since Maimonides invoked no observational evidence.
A young Earth has never been part of Islamic teaching. However, the deplorable Adnan Oktar (“Harun Yahya”) has popularised Young Earth creationism in the Muslim world, hence the need to discuss the matter here. Moreover, it gives me the opportunity to highlight some of the intellectual achievements of two of the most eminent scholars of the Islamic Golden Age, al-Biruni and Ibn Sina, both of whom correctly inferred the antiquity of the Earth from geological arguments.
Figure 7: Geological time spiral (Source)
Ibn Sina, fossils, and strata
Figure 8: Illustration of Avicenna’s “Sequence of Events to the Formation of Mountains” Contribution of Ibn Sina to the development of Earth Sciencesby Munim al-Rawi
Ibn Sina’s work was well known in late mediaeval Europe, and is even mentioned by Chaucer. The material we consider here was translated into Latin as early as around 1200 C.E. by Alfred of Sareshel, who attributed it to Aristotle himself.