Category Archives: History of Science

The “scientific method”, a needless stumbling block. With a note on falsification

Science does not have a separate special method for learning about the world, the “scientific method” as taught in schools is a damaging illusion, and the falsifiability criterion has itself been falsified

Below, R: How not to; “The Scientific Method”, as inflicted on Science Fair participants. Click to enlarge

Consider this, from a justly esteemed chemistry text:

Scientists are always on the lookout for patterns.… Once they have detected patterns, scientists develop hypotheses… After formulating a hypotheses, scientists design further experiments [emphasis in original]

Or this, from a very recent post to a popular website:

The scientific method in a nutshell:
1. Ask a question
2. Do background research
3. Construct a hypothesis
4. Test your hypothesis by doing experiments
5. Analyze your data and draw conclusions
6. Communicate your results [emphasis in original]

Then, if you find yourself nodding in agreement, consider this:

Since a scientific theory, by definition, must be testable by repeatable observations and must be capable of being falsified if indeed it were false, a scientific theory can only attempt to explain processes and events that are presently occurring repeatedly within our observations. Theories about history, although interesting and often fruitful, are not scientific theories, even though they may be related to other theories which do fulfill the criteria of a scientific theory.

If you are familiar with the creation-evolution “controversy”, you may well suspect that last example of being so much creationist waffle, intended to discredit the whole of present-day geology and evolutionary biology. And you would be right. This quotation is from Duane Gish, a major figure in the twentieth century revival of biblical literalist creationism, writing for the Institute of Creation Research.1

L: Mike Pence, ” [N]ow that we have recognised evolution as a theory… can we also consider teaching other theories of the origin of species?”

Such nonsense isn’t funny any more, if it ever was. The man who may very soon find himself President of the United States is an eloquent spokesman for creationism.

And yet Gish’s remarks seem to follow from the view of science put forward in the first two excerpts. What has gone wrong here? Practically everything. Read the rest of this entry

Creationist nonsense on geology; the odd case of Prof McIntosh D.Sc.

Image result for andy mcintoshCatastrophism versus gradualism; this controversy was laid to rest by TH Huxley in his 1869 Address to the Geological Society, but UK Young Earth Creationists persist in parading the corpse as if it presented a living challenge to current thinking. Perhaps it appeals to their absolutist binary mindset.

McIntosh himself is a member of the group mendaciously mislabelled Truth in Science, which distributed the equally mendacious neo-creationist tract Exploring Evolution to UK schools some years ago, and is an author of the error-saturated Origins, Examining the Evidence, published by that group. BCSE has published a detailed review of Exploring Evolution here.

This piece by my friend, the geologist historian Anglican priest Michael Roberts, will tell you more about McIntosh’s writing than you wish to know, but will convey a wealth of fascinating geological and historical information in the process.

Peddling and Scaling God and Darwin


Image result for andy mcintosh

One of the best selling British creationist books is Genesis for Today by Andy McIntosh, which is now in its 5th edition.

Most of the book is a popular exposition of Genesis 1 to 11 – and some of it I agree with, but not his insistence that it is literal history.

In Genesis for Today McIntosh gives three scientific appendices, which are much the same in the 1st and 5th editions.  I could either go through and nit-pick his geological errors or consider them under main headings. I have chosen the latter.

Image result

Most would think that a professor in a scientific discipline at a leading university (with a first-rate geology department) would be able to make a reasonable showing on geology.Many amateurs and non-geologists I’ve met in geological societies have a clear grasp.

From the whole of his book, other writings and…

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The Woman Who Studied the Sun

File:Cecilia Helena Payne Gaposchkin (1900-1979) (3).jpg

Cecilia Payne-Gaposhkin at work; Smithsonian Institute Archives via Wikipedia

I just came across this piece by John Gribbin, interesting for many reasons.
Glasgow University started awarding degrees to women in 1892; contrast Cambridge University’s 1948.
Auguste Comte, 1835: “We will never be able to determine the chemical composition of the stars”.
1802, Wollaston observes Fraunhofer lines
1814, Fraunhofer independently observes Fraunhofer lines. Perhaps a reader can tell me why they are named after Fraunhofer, not Wollaston
1859, Kirchhoff (of circuit laws fame) and, independently, Bunsen (of Bunsen burner fame) match Fraunhofer lines to atomic spectra, infer chemical composition of stars
1868, Lockyer correctly identifies third solar Fraunhofer line in “sodium yellow” region as due to a new element, names it “helium”
1892, Glasgow University starts awarding degrees to women
~1923 (see below), Cecilia Payne (later Payne-Gaposhkin) completes studies at Cambridge, but cannot formally graduate because she is a woman
1925, Cecilia Payne gains Ph.D. from Radcliffe; unravels highly complex (see below) Fraunhofer lines of stars; shows that, contrary to all then current expectation, stellar composition is dominated by hydrogen and helium
1948, Cambridge University starts awarding degrees to women


Posting this in response to a question I was asked.  It is essentially an extract from my book 13.8

Cecilia Payne won a scholarship to Newnham College, Cambridge (the only way she could have afforded a university education) in 1919. She studied botany, physics and chemistry, but also attended a talk by Arthur Eddington about the eclipse expedition on which he had famously “proved Einstein right” by measuring the way light from distant stars was bent by the Sun. This fired her interest in astronomy, and she visited the university’s observatory on an open night, plying the staff with so many questions that Eddington took an interest, and offered her the run of the observatory library, where she read about the latest developments in the astronomical journals.

After completing her studies (as a woman, she was allowed to complete a degree course, but could not be awarded a degree; Cambridge…

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Clay tablet casts new light on origins of Genesis are puzzled by the significance of a cuneiform tablet dating to around 1400 BCE, recently discovered during excavations in Sumeria. A tentative translation, still controversial, is as follows:

“From Moses, General Secretary of the Brickmakers Union, Land of Goshen, greetings.

Moses Michaelangelo September 2015-1.jpg

Moses, contemporary scupture, holding what is thought to be this tablet

From my measurements of the sedimentology of the Nile Delta, I estimate that the river has been depositing sediment there for many tens of thousands of years. Concerning the origin of mankind, I am now convinced that we, the jabbering creatures of West Africa, and the knuckle-walking giants who live beyond Numidia are different species of the same family.

However, You-Know-Who has told me to come up with a simplified version of the story, which my members will be more capable of understanding.

Nile Delta in ancient times (Wikipedia)

I wonder if there is anything suitable among your own traditional mythologies. In particular, since the Internet has not yet been invented, can you send me by camel post a preprint of Enuma Elish. And if possible, an advance copy of your pending publication, The Flood of Gilgamesh. Read the rest of this entry

My “Islamic Foreshadowing of Evolution” has appeared in Muslim Heritage.

I am published in Muslim Heritage.

Islamic Foreshadowing of Evolution (full article here).

Gloriously illustrated by the Muslim Heritage editorial team; so much for the common impression that Islam forbids representational art.

Images assembled by Muslim Heritage editorial team

I briefly describe present-day evolution science, and why the evidence for this is considered overwhelming, having earned endorsements from national academies worldwide, including the academies of several predominantly Muslim countries.

I show how Muslim thinkers (especially Al Biruni and Ibn Sina) went beyond Aristotle’s mere assertion that the Earth is old (for Aristotle, infinitely old), by observing and discussing fossils and sediments in an unmistakably scientific manner. I also discuss widespread claims that Islamic scholars had anticipated modern evolutionary thought, and come to the sad conclusion that these are not warranted. What is being described, by sources as diverse as the poet Rumi, the Ikhwan al-SafaI (Brethren of Purity, 8 – 10 C CE), and the pioneer social scientist Ibn Khaldun in 1377 CE, is the Great Chain of Being, derived from Aristotelian thought, and represents stages of development, but does not imply common descent, or change over time. I also look at the claims made on behalf of al Tusi, but fear that these will not stand examination.

The one clear example that I do find of anticipation of the central ideas of mutability of species and common descent comes from al Jahiz’s delightful Kitab al-Hayawan (Book of Living Things, 9 C CE), where among much other interesting material (though the story of birds cleaning crocodiles’ teeth is, alas, suspect) he correctly suggests common ancestry for wolves, dogs, and foxes.

The Crocodile from The Book of Animals by Al-Jahiz Credit: © Veneranda Biblioteca Ambrosiana, Milan, Italy/Bridgeman Images, via PhotoEditor61

I would be delighted to hear of other examples, provided these are accompanied by links to reliable translations (I regret that I cannot read Arabic or Persian) of the original material. I am of course aware of a great deal of twentieth and twentyfirst century literature that makes such claims, but on examination I have so far found these to be simply back-projection. We must also remember that earlier thinkers must be judge in the context of their own times, that they were unaware of the significance that observations would require at a later stage, and that to judge them according to how well they happen to agree with us, with our vastly expanded knowledge base, is unhistorical and, indeed, patronising.

On the relationship between evolution and Islam, I have this to say:

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 account1). 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,2 and the scientific academies of Bangladesh, Egypt, Indonesia, Morocco, Pakistan, Palestine, Turkey and Uzbekistan have joined others worldwide in affirming evolution.3

On the Muslim Heritage Facebook page, my article has received over 2000 “likes”. I am grateful to the editorial staff of Muslim Heritage for inviting me to contribute this article, and to Ehab Abouheif, Jim Al-Khalili, Glenn Branch, J. E. Montgomery, Cem Nizamoglu, Rebecca Stott, and Douglas Theobald for helpful discussions.

I will be posting a fuller summary of my rather lengthy article in due course.

1] Marwa Elshakry, Reading Darwin in Arabic, 1860-1950, University of Chicago Press, 2013.

2] “Muslim leaders urge Islamic community to rethink evolution theory” by Omar Shahid

3] IAP on the Teaching of Evolution


Is “The Imminent Demise of Evolution” still imminent?

The demise of evolution, and of the geology necessary to support it, has been imminent since 1825. I hear and tremble.

My friend the rev Michael Roberts has reblogged my link here, with reference to his own experience. Michael is Anglican Priest, geologist, and historian, and has been following Creationist infiltration into the UK churches  for some decades.

Troy Britain’s piece reblogged here refers in turn to G.R. Morton’s classical compilation. Morton’s piece was originally posted on Answers in Science. The link from Morton to Answers in Science failed to work for me, but I am happy to say  that a direct link, here, works admirably as a source and resource.

Playing Chess with Pigeons

Ten years ago, in 2006, intelligent design creationistWilliam Dembski predictedthat in a decade evolution would be toast:

LOUISVILLE, Ky. (AP) – To William Dembski, all the debate in this country over evolution won’t matter in a decade.

By then, he says, the theory of evolution put forth by Charles Darwin 150 years ago will be “dead.”

Yeah, well…

Meanwhile I stumbled uponthis today (dated 11-17-2016) from young Earth creationistRichard William Nelson:

Despite a flood of challenges since the publication of The Origin of Species in 1859 by Charles Darwin and more than 150 years of unprecedented scientific efforts in the history of mankind to prove otherwise, the evidence examined in nature tooled with unprecedented technology continues to be compatible with the Genesis record written by Moses…

…Evolution, once a theory in crisis, is now in crisis without even a cohesive unifying theory.

Biological evolution…

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Atoms Old and New, 2: From Newton to Einstein

Part 1 of this series, “Atoms Old and New: Atoms in Antiquity” can be read here.

The transition to modern thinking

“It seems probable to me, that God in the beginning formed matter in solid, massy, hard, impenetrable, movable particles… even so very hard, as never to wear or break in pieces; no ordinary power being able to divide what God Himself made one in the first creation.” So wrote Sir Isaac Newton in his 1704 work, Opticks. Apart from the reference to God, there is nothing here that Democritus would have disagreed with. There is, however, very little that the present-day scientist would fully accept. In this and later posts, I discuss how atoms reemerged as fundamental particles, only to be exposed, in their turn, as less than fundamental.

The scientific revolution and the revival of corpuscular theory – 1543–1687

Read the rest of this entry



Darwin as a young man, watercolour by George Richmond, via Wikipedia

An excellent historical summary by my friend Michael Roberts, who has himself revisited the sites that Darwin explored in Wales. Darwin the geologist and Darwin the naturalist are inseparable.

Peddling and Scaling God and Darwin


Darwin concluded The Origin of Species with this magnificent paragraph;

It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the external conditions of life, and from use and disuse; a Ratio of Increase so high as to lead to a Struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms…

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Then and now; Darwin, Agassiz, global warming, and lakes that vanish overnight

Glen Roy is a valley in the Western Scottish Highlands, just south of the Great Glen (home to Loch Ness), and draining through Glen Spean to Loch Linnhe, an inlet of the Atlantic. It is remarkable for the presence of the Roads, a series of parallel, almost horizontal, grooves in the hills on the sides of the glen. Clearly shorelines; but of what body of water? And why are there more than one of them?


From Darwin, C. R., Philosophical Transactions of the Royal Society 129: 39-81, 1839. Observations on the parallel roads of Glen Roy, and of other parts of Lochaber in Scotland, with an attempt to prove that they are of marine origin.

Darwin thought the Roads represented vanished marine shorelines, one above the other as the result of vertical movement. Agassiz explained them, rather, as successive shorelines of a glacial lake, now vanished because the retaining glacier has melted away. If so, and if global warming is real, we might expect to see vanishing lakes today, as the glaciers retreat. We can, and we do, as my friend Peter Hess explains.


Sedimentary (greywacke) erratic (approx. height 1 m) on glaciated slopes around Dunglass Crag, near Glasgow, transported from original location some 30 km to the North

Charles Darwin visited the Glenroy area in 1838, two years after his return from his round the world voyage on the Beagle. During that voyage, he had examined the geology as well as the plants and animals of the places he visited, and among them was the coastal area of Chile. This is marked by raised beaches inland where once had been shoreline, and Darwin correctly described these as the effects of uplift, which we now know to be driven by plate tectonics. So it was natural that Darwin should have applied a similar explanation to the Roads, suggesting that the Cairngorms, like the Andes, were a zone of uplift, and that the Roads were ancient beaches of the Atlantic, now some ten miles away. The alternative theory, that they represented shorelines of an ancient lake, ran up against a seemingly conclusive objection; such a lake could only have formed if there had been a barrier across the valley, but there was no trace of this.

Only a year later, the Swiss naturalist Louis Agassiz visited the area. He had just published his Ice Age theory, and in the Highlands he found plenty of evidence to support it; scratches on bedrock caused by the passage of glaciers, erratics (boulders far from their parent rock formations),  and moraines (piles of rock rubble that had been carried by glaciers, left in place when the glacier melted).


A glacier-sculpted landscape. The hard basalt of Dunglass Crag, an ancient volcanic plug, has protected the softer rock downstream (right in photograph) from erosion

Evidence of this kind is not difficult to find throughout much of Scotland. I saw some of it myself earlier this month a few miles from Glasgow as a student on Glasgow University extension course (see illustrations). Agassiz realised that his ice age theory also provided the correct answer to the mystery of the Roads. Yes, there had been a lake, and yes, the roads did represent the shorelines at different times, carved into the sides of the valley by fierce freeze-thaw cycles. As for the barriers holding the lake in place at different levels over the course of time, they were a series of long vanished glaciers.

We now know that Agassiz was basically correct. Indeed, we can trace a whole series of glaciations, not just a single ice age. And Darwin was right in thinking that the area has experienced uplift; it could not fail to do so as the weight of ice above it melted away.


Poorly sorted rubble deposited by the glacier near the foot of the Crag

Later Darwin was to write of his paper on the Roads as his greatest blunder. He had visited Snowdonia in North Wales in 1831, as a student companion of the noted geologist Adam Sedgwick, who had been looking for fossils. In his Autobiography (p. 70) he laments how

“neither of us saw a trace of the wonderful glacial phenomena all around us; we did not notice the plainly scored rocks, the perched boulders, the lateral and terminal moraines. Yet these phenomena are so conspicuous that … a house burnt down by fire did not tell its story more plainly than did this valley.”

But it took Darwin several years to reach this point, and even then he persisted for a while with hybrid explanations, in which icebergs rather than retreating glaciers had deposited at least some of the erratics.


“Darwin’s boulders” in Cwm Idwal, Snowdonia, North Wales. Darwin had recognise these as glacial by 1842

Agassiz rejected Darwin’s concept of evolution when it was published twenty years later, but this does not seem to have diminished Darwin’s respect for him. Belief in the fixity of species was, in the 1860s, understandable conservatism, even if now, 150 years later, it is no more than deliberately cultivated ignorance.

The present is key to the past. It follows that the past can increase our understanding of the present. And so it is in this case. The glaciers of Switzerland are receding. Those of the southern Andes are receding even faster. Among them is Chile’s Colonia glacier, which dams a lake, Lake Cachet 2, some 3 square kilometers in area. As the glacier shrinks and weakens, it becomes progressively less able to hold back the water of the lake, which now periodically bursts through; on one recent occasion, the lake emptied itself overnight.


Lake to sandy valley overnight

The overflow channel through which the vanished Loch Roy must have drained can still be detected as an abrupt narrow valley in the surrounding hillsides. The draining of Lake Cachet II sent 200,000 tonnes of water overnight down Chile’s main river, and caused giant waves as far as the Pacific Ocean, 60 miles away.

Since Agassiz and Darwin examined the roads of Glen Roy, the earth’s mean surface temperature has increased by roughly 1oC, with another 0.5oC in the pipeline even if emissions were to be stabilised at the same levels as in the year 2000.

Which, of course, they won’t be.


Global mean surface temperature change from 1880 to 2015, relative to the 1951–1980 mean. The black line is the annual mean and the red line is the 5-year running mean

Darwin’s drawing of the Roads from Darwin Online.  Dunglass Crag, photos by author. Darwin’s boulders photographed by Michael Roberts. Lake Cachet II images via NCSE. Global temperature anomaly graph from NASA GISS via Wikipedia

More on receding glaciers at World Glacier Monitoring Service  and the US Government’s National Snow and Ice Data Center

h/t Michael Roberts, Dana Nuccitelli, Peter Hess. An earlier version of this post appeared in 3 Quarks Daily.

Science in the World of Islam, 1: The Syllable Al-

As in Alcatraz; Alcove; Alfalfa; Alcohol; Alkali; Alizarin; Almanac; Alchemy; Alembic; Algol; Almagest; Algebra; Algorithm; Alhambra

The syllable Al- is Arabic for “The”, and is attached to the beginning of the word to which it applies.

Like English today, or Latin in Renaissance Europe, the dominant language of learned discourse for several centuries was Arabic. Arabic-speaking scholars translated the great works of the Greek philosophers and scientists, as well as studying them in the original, did likewise for the texts of Indian mathematics (from which we derive our modern “Arabic” numbering system), and made important discoveries of their own. Spain was where the worlds of Islam and of Western Christianity met, fought, and mingled for more than seven hundred years, and it is mainly through Spanish that Arabic words have entered the English language.


Prison block, Alcatraz (now a museum)

Alcatraz, an island in California famous for its prison (left), was named by the Spanish explorers for the pelican (Arabic al-qadus, the water carrier), which they wrongly believed to carry water in its bill. In a further misapplication, the word has passed into English as the name for a completely different bird, the “Albatross”. Alcove (al-qubbah, the arch) reminds us of the glories of Moorish architecture, as in the Alhambra (or the red house) in Granada. This building was decorated with abstract designs (Arabesques) of great intricacy, whose patterns show so subtle a use of geometry and symmetry that they are studied by mathematicians even today. Alfalfa (from the Arabic name for the plant) is grown for hay in dry climates, such as that of Spain. The syllable al also occurs in numerous place names. The Algarve to us is the south of Portugal; to the Iberian Arabs, it was al-Gharb, the West. A very common combination is with wadi, valley, as in Guadalquivir (al-wad al-kebir, the Mighty River, the island of Guadalcanal in the Pacific (named after a town in Spain, wad-al-Kanat, valley of merchant stalls), Guadalajara (wad-al-Hajara or valley of stones) in Spain and Mexico. There are even a few Arabic-Spanish or Arabic-Latin hybrid names, such as Alicante (al– tacked onto the Roman name Lucentum, or City of Light) or Guadalupe (wad-al-lupus, valley of the wolf) But most of the Arabic al- words in common English use refer to the Arabic achievements in science and mathematics.


Decorated arch, Alhambra (click to enlarge)

Alchemy, algebra, and Arabic numerals

Historically, the West has failed to give anything like due credit to the Arabic contribution to knowledge. A century ago, the justly renowned physicist, philosopher, and historian Pierre Duhem described the “wise men of Mohammedanism” as “destitute of all originality”.[1] I myself, somewhat more recently, was taught at school that the Renaissance was brought about by Byzantine scholars who alone had been guarding the flame of knowledge kindled in classical times, and who, after the fall of Constantinople to the Turks in 1453, were dispersed throughout Europe. This account is as unhistorical as it is patronising. We can trace the golden age of Arabic science to the eighth century translation project, centred on Baghdad, which made the thought and knowledge of the Greece (and Persia and India) available in Arabic. And we must in turn acknowledge, as among the events leading up to the Renaissance and what we call “the” Scientific Revolution, the translation project centred on Toledo, that four centuries later was to translate the work of Arabic into Latin.

Our system of writing numbers was invented in India, from where Persian scholars brought it to the Arabic world. By the tenth century it had spread from there, through Spain, to the rest of Europe, so that we still refer to Arabic (as opposed to Roman) numerals. (The shapes of the actual numerals that we use follow those of the western part of the Islamic world, and have a clear family relationship to those from the eastern part, which are the ones used in Arabic writing today.)  The word algorithm originally meant calculation with Arabic numerals. The word preserves the name of the Persian mathematician and polymath al-Khwarizmi,[2] who had by around 825 CE worked out the procedures for doing arithmetic as we do, using zero, and positional notation for powers of ten. (If you think this was only a minor advance; just try doing long multiplication using Roman numerals. Masochists are invited to try long division.) The word “algorithm” has now acquired an interesting new meaning, as a procedure or set of rules for calculating an answer, and much of computing science is devoted to finding the best algorithm for a given class of problem.

AL-Khwarismi statue

Statue of al-Khwarismi, Uzbekistan

Al-Khwarismi’s writings also give us the name, and the concept, of algebra (al-jebr, sometimes translated as “balancing” or “completing”), including the rules for solving quadratic equations by completing the square. One other possible meaning of the word is “uniting” or “joining”, and in sixteenth century England it also meant “bone-setting”.

Mathematics finds practical application in astronomy. This is a science of great utility for tracking the seasons, and also for navigation (the Arabs traded as far as Indonesia), and orientation (Moslem worshippers would need to know, as exactly as possible, the correct direction to Mecca). Here Arabic scholars were greatly helped by their access to the work of the Greek astronomers of Alexandria. The Greek theory of planetary motions placed the Earth at the center, with the other heavenly bodies following epicycles, or wheels within wheels. This theory was fully developed by the astronomer Ptolemy in a work still referred to by the name of its translation into Arabic, the Almagest (Arabic al-, the; Greek megisti, greatest). However, Arabic astronomers made original discoveries in both observational and theoretical astronomy. They followed their Hindu precursors in anticipating Copernicus’ shift of the center of the revolutions from the Earth to the Sun, and developed the sophisticated mathematics required to handle the implications of such a shift. When they discovered that a star in the constellation Perseus showed varying intensity over time, they called it Algol, the ghoul (yes; ghoul is also Arabic), because it went against Aristotle’s view that everything above the moon was perfect and unchanging. The predicted motions of the moon (important in Islamic religious observance) and planets, together with a list of dates for planting, can of course be found in an almanac (al-manakh, the calendar).

The language of chemistry in particular shows evidence of its origins in the Arabic science of alchemy (al-Khemiya; from Greek chimeia, art of refining metals). If today we think of alchemy as a benighted precursor to the true science of chemistry, that is just a trick of historical perspective, and indeed the two terms were used more or less interchangeably, both in the Arabic-speaking world and in Europe, until relatively recent times.[3] While greatly discredited by its later practitioners in Europe, alchemy was the first serious attempt to relate observed chemical changes to an underlying theory of elemental composition. One piece of apparatus much used by the alchemists was the alembic (al-anbiq, the vessel, from greek ambix). Arabic craftsmen also developed the practical aspects of the subject, extracting the red dye alizarin (al-asarah, the juice) from the madder plant and developing the process for binding it to cotton. They also extracted potassium carbonate from the alkali (al-qali, the ash) made by burning seaweed, and this process was the main source of alkali for soap making and other purposes until the 19th century. The ladies of the Middle East used al-kohl (the powdered antimony) in eye makeup, a practice mentioned by the Prophet Ezekiel, who did not approve. This, strangely, is the origin of our word alcohol. Over time, this word has changed its meaning completely, from powdered antimony, to any fine powder, to a distilled essence used to suspend the powder, to the intoxicating substance ethyl alcohol (strictly forbidden to Moslems), and finally, in modern scientific usage, to any substance containing a similar carbon-oxygen-hydrogen grouping.


Phases and eclipse of the Moon, from al-Biruni’s Kitab al-Tafhim (Elements of Astrology}

Science, as I have mentioned, was pushed forward by its practical applications. Observational and theoretical astronomy, essential to navigation at that time, were highly advanced. Anatomy and medicine were also well developed, and, more than three hundred years before William Harvey, the Egyptian physician al-Nafis worked out that blood circulates through the lungs. Optics was well advanced, with knowledge of refraction and lenses, the laws of reflection from a curved surface, the fact that in vision the eye focuses incoming light, and the cause of the rainbow, which involves two refractions and one reflection from a curved surface. These discoveries in optics involved both sophisticated calculations (sine, cosine, and tangent functions were known and used), and true experiments involving water-filled bowls and light passing through slits. Arabic alchemists also conducted true experiments, and realized that sulfur and mercury were fundamental “principles” (we would say elements), although they failed to free themselves from the Aristotelian doctrine that the different metals were interconvertible.

While consciously and conscientiously built on classical achievements, Arabic science at its best was original, adventurous, and (especially in astronomy and geography) supported by meticulous observation. One of the greatest of Arabic astronomers and polymaths was al-Biruni, 973 -1048 (in 1970, the crater Al-Biruni on the Moon was named after him). He contributed to the development of observational instruments and numerical and geometric techniques, and recognised that the earth rotated daily on its axis, but was neutral on principle regarding whether the earth went round the Sun once a year, or vice versa, on the grounds that these two were observationally equivalent. He also very clearly distinguished astronomy from astrology, which, as he explained, had been concocted by astronomers to satisfy the popular demand for practical benefit from their science.[4] His other achievements include the recognition of the nature of fossils as petrified plant and animal remains, the realisation that valleys are formed by erosion, and the inference from the nature of the soil and the gradation in size of buried stones, that the plain of the Indus had been formed from river-borne sediments.

Al-Biruni’s contemporaries included Ibn al-Haytham (Alhazen), 965-1039, and Ibn Sina (Avicenna), 980-1037.  Ibn-Sina and al-Buruni agreed on the nature of fossils, the formation of river valleys and alluvial plains, and the implied antiquity of the Earth. Ibn-Sina’s greatest achievements, however, were in the area of medicine. These made his name familiar even in late mediaeval Europe, and he is referred to as an authority on poisons in Chaucer’sCanterbury Tales. Ibn al-Haytham was employed by the notoriously eccentric Egyptian Caliph al-Hakim to supervise engineering works intended to regulate the Nile floods. This proving impossible, he fell from favour, and it is said that he found it prudent to pretend madness. He was placed under house arrest, and his Book of Optics ranks, along with John Bunyan’s Pilgrim’s Progress, Adolf Hitler’s Mein Kampf, and Bertrand Russell’s Introduction to Mathematical Philosophy, among notable works written in prison.

Much Islamic art was highly mathematical. It involved a knowledge of all the ways in which the two-dimensional space of a wall could be symmetrically divided by tiling,[5] and anticipated in its practice even such twentieth century developments as color symmetry and five-fold pseudosymmetry.


Tiling, Alhambra, exhibiting colour symmetry (click to enlarge)

I have carefully referred to “Arabic” scholars and artisans, rather than to “Arabs.” “Islamic” might seem more accurate, for a culture that included Persia (Iran) and much of Central Asia, but the culture we are discussing borrowed freely from pre-Islamic sources, and many of the participants were not themselves Muslims. Throughout its greatest period, from the eighth to the thirteenth centuries, it was a multicultural society, with Zoroastrian, Jewish, and Christian scholars and craftsmen all contributing to its rich intellectual life. Ali ben Isa, the most noted Arabic oculist, was a Christian. Saladin’s family physician, Moses ben Maimon (Maimonides), was a Jew. The Persian mathematician Omar Khayyam, who systematized the solutions of cubic equations (as well as writing the lyric verse for which he is now best remembered in the West) was a free-thinking skeptic.[6] The mathematician al-Khwarizmi, whom we have already met, worked in Baghdad at the heart of the Arab world but borrowed freely from Hindu sources; both he and al-Biruni hailed originally from Central Asia, and Ibn-Sina was Persian.

Islam itself was far from being a single rigid structure. The doctrinal divisions between and within Sunni and Shi’a branches were (and are) as profound as those in Christianity between Catholic and Protestant, and in Sufism (which continues to flourish; you can now download Sufi music online) Islam has a mystical tradition that transcends all orthodoxies.

Arabic science and mathematics formed the bridge between the achievements of the ancient Greeks, and the emergence of modern science in Europe in the sixteenth and seventeenth centuries. By this I do not mean to imply that it was merely a passive vehicle, but rather that all of these should be seen as part of the same ongoing activity. To the enlightened, science was not regarded as hostile to religion; on the contrary, the visible world was seen as testifying to its invisible Creator. When the Arabs first over-ran the Hellenized eastern Mediterranean, a deliberate decision was made to translate the Greek texts available there into Arabic, and it was by way of these Arabic translations, in the multi-cultural societies of late medieval Spain, that this ancient knowledge was restored to pre-Renaissance Europe.

1] Physics, history of; Catholic Encyclopaedia, 11:48 (1911).

2] Or, to give him his full name, Abu-Jafar Mohammed ibn-Musa al-Khwarizmi, “Father of Jafar, Mohammed son of Moses, the man from Khiva (now in the central Asian republic of Uzbekistan)”

3] For this observation, among others here, I am indebted to Jim Al-Khalili’s Pathfinders, Allen Lane, 2010.

4] S. Pines, Isis, 55(3), 343, 1964

5] Technically, the two-dimensional space groups

6] We consider him part of this same cultural community, although, individual in this as in so many other things, he wrote in Persian

Alcatraz prison, (c) David Corby 2006 via Wikipedia; Creative Commons license. Statue of al-Khwarismi, Uzbekistan, Image by © Melvyn Longhurst/Corbis via the blog Missed in History. Alhambra architecture and tiling, photos by author; click to enlarge.

This piece originally appeared in 3 Quarks Daily

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