The Scientific Method – Part IV (The Golden Age of Islam)

Introduction

"When hearing something unusual, do not preemptively reject it, for that would be folly. Indeed, horrible things may be true, and familiar and praised things may prove to be lies. Truth is truth unto itself, not because [many] people say it is." Ibn Al-Nafis, Sharh' Ma'na Al Qanun.

Do you remember when you were in grade school, first learning about science and the scientific method and were told about the Islamic Golden Age? How about the day when you were introduced to algebra and learned its name was Arabic for "restoration"? Do you remember how your teacher told you about the great Islamic scholars of Baghdad and Cairo who translated Sanskrit, Persian, Greek, and Latin into Arabic, and stored the works in libraries larger than even the Great Library of Alexandria of classical times? Do you remember learning how the city of Baghdad had been the largest city in the world for centuries, with over a million people at a time when London had at best 20,000?

For me, unfortunately, none of the above things ever happened. The thousand years between the fall of Rome and the Renaissance was at best rushed through, and mostly with Western highlights. I learned about the Goths, then the Muslim Conquest, then the Franks and Charlemagne, then the Vikings (counting Normans here, too), then the Crusades (the ones the West won in detail, the others - there were nine - in less detail), then the Mongol Conquest, then Marco Polo, then the Black Death, which is presented in an "it's always darkest before the dawn" sort of for way, and then finally the Renaissance, at which point we slowed down again and started learning names and dates in earnest.

For many of us, there is a giant hole in history we like to call the "Dark Ages". The Dark Ages were anything but dark in the Islamic world. I can't hope to cover the history of the Caliphates in this blog. It would pull the discussion way off topic from my desired goal of examining the development of Epistemology, specifically the Scientific Method. If, however, you someday find yourself bored and are looking for something to do, I recommend reading about the Golden Age of Islam. To help understand how the Islamic advancements to the scientific method were possible, I will provide a brief historical overview to bring us up to speed, but my 300 words below barely scratch the surface.

The Golden Age of Islam

The Islamic Golden Age is generally considered to have begun in 750 AD after the Battle of the Zab and the establishment of the first Abbasid Caliphate and to have ended with the burning of Baghdad by the Mongols in 1258 AD. With the ascension of the Abbassid Caliphate (so named because they were descendents of the prophet Muhammad's youngest uncle, Abbas ibn Abd al-Muttalib), the capital of the Islamic world was moved from Damascus to the newly-built Baghdad in 762 AD. Baghdad quickly became a significant cultural, commercial and intellectual center for Islam. A unique characteristic of the Abbasid Caliphate, often considered a trait derived from Persian influence, was a rapacious desire to collect knowledge. Works in Greek, Latin, Persian, and Sanskrit were translated meticulously into Arabic, cataloged, and then housed in libraries. The newly-learned technology of paper was used instead of fragile papyrus or expensive parchment. Many libraries were built in Baghdad, including a great library called the House of Wisdom.

The House of Wisdom, through the sponsorship of the Abbaisid Caliphs, grew to become the premiere learning center in the world. In the beginning it concentrated on acquiring and translating (into Arabic) any and all works that could be found. Soon, however, the works started to be those of Arab scholars who built upon and extended the knowledge of the classical works. For over 400 years the House of Wisdom in Baghdad and later the House of Knowledge in Cairo (founded in 1004 AD) were centers of learning. Scholars from every country would travel to these cities to study and learn, much as they had to Alexandria and its great library a thousand years earlier. Scholars associated with the House of Wisdom were Sahl ibn Haroun, Muhammad ibn Musa al-Khwarizmi (Mathematician), Mohammad Jafar ibn Musa and al-Hasan ibn Musa (Engineers), Sind ibn Ali (Astronomer, Mathematician), Yaqub ibn Ishaq al-Kindi (Physician, Mathematician), Hunayn ibn Ishaq (Translator), and Sabian Thabit ibn Qurra (Mathematician).


Alhazen

How do we see? This was a subject upon which ancient greats had disagreed. Ptolemy and Euclid believed that the eyes emitted light to see. Aristotle believed objects emitted particles into the eyes. To resolve this issue, Alhazen (Abu Ali al-Hasan ibn al-Hasan ibn al-Haythan) systematically employed experiments and mathematics to confirm or reject these hypotheses.

In Part III of this series, it was shown that Aristotle combined induction and deduction to derive truths. Induction was used primarily as a method of determining first principles which could be used as premises. Then new truths were acquired bv deductive reasoning from these premises. As was stated in that blog entry, this was a monumental step forward for the acquisition of knowledge.

Alhazen realized that induction could be used for more than just determining first principles to be used as premises; induction could also be used to support or disprove premises. In other words, induction could provide truths like deduction. The one caveat is that the truths obtained through inductive methods, though highly probable, could never be definite. Deductive truths, on the other hand, can be definite. One, however, could minimize the uncertainty of inductive truths by controlled scientific observation (as opposed to just scientific observation - collecting empirical evidence). Controlled scientific observation seeks to reduce variables and focus on particular aspects of a problem. The idea being that any single, controlled observation itself was useful only as a part of a corpus of many controlled observations. Today we call controlled scientific observation "experiment".

Alhazen constructed many experiments. Some were used to contradict the theory that light was emitted by the eyes, some were used to contradict the particle theory of light, and some were used to observe the properties of light. Eventually, and after many years of experiments, Alhazen concluded that light reflected off objects to the eyes, a brand new theory born from his careful systematic inductive method.

Scholars of Alhazen's day and later refined the experimental approach to obtaining truth. Al-Biruni developed methods to prevent systematic errors and observational biases and advocated repeating experiments to qualitatively arrive at a "common sense value of measurement" (if you measure 5 times and you get 5.9, 5.8, 6.2, 6.2, 5.9, then a commonsense value would be around 6.0). Avicenna emphasized that hypothesis should come before experiments, not after. This would prevent observational bias.

Al-Jabr

"That fondness for science, ... that affability and condescension which God shows to the learned, that promptitude with which he protects and supports them in the elucidation of obscurities and in the removal of difficulties, has encouraged me to compose a short work on calculating by al-jabr and al-muqabala , confining it to what is easiest and most useful in arithmetic." - Al-Khwarizmi, Al-Kitab Al-Mukhtasar Fi Hisab Al-Jabr Wa'l-Muqabala

Muhammad ibn Musa al-Khwarizmi died about 100 years before Alhazen was born. He was a Persian scholar in the early days of the House of Wisdom in Baghdad. The term "Algebra" comes from his 820 AD book "al-Kitab al-mukhtasar fi hisab al-jabr wa'l-muqabala", in which he provides known rules (at the time) for solving quadratic equations. This is considered to be the foundation of modern algebra.

Why is this significant? Well, we all know mathematics is important to modern science. To the ancient Greeks, mathematics was for the most part geometry and number theory. If you showed Greek mathematicians a formula, they would ask what in geometry it corresponded to. Algebra separates the formulas from the geometry. In algebra, the formulas are the "thing". They are analyzed, characterized, and systematically solved. That is not to say that they aren't connected to geometry, but in algebra the formulas aren't studied for a geometric end; they are studied in their own right.

As I described earlier, the Islamic scholars were translating everything they could get their hands on into Arabic. This meant Sankrit (India) works as well as Greek and Latin. The result was the combination of many different cultures' mathematics into a single, more useful mathematics. The efficient was kept (Hindu numerals and decimals from Sanskrit and Persian) and the cumbersome was discarded (roman numerals, greek numerals). The math born in the Islamic golden age was much more expressive and flexible that earlier math. It was at this time that it began to be thought of in the modern sense. With better mathematics, better theories could be derived.

Alhazen also used geometry to explain the optical phenomenon he saw through his controlled observations (experiments). It wasn't the first time science and math had been tied together, but because of the significant advances made by Islamic scholars in mathematics, Alhazen and other Islamic scientists had many more mathematical tools with which to describe the world.

Conclusions

Significant advances in mathematics, especially the untethering of mathematical formulas from geometry, the adoption of Arabic-Hindu numerals, and the incorporation of decimals, altered the nature of mathematical inquiry and provided scientists with more mathematical tools with which to understand nature. The consolidation of knowledge from four massive cultures (Hindu, Greek, Persian, and Roman) into libraries in Baghdad and Cairo created an easily accessible and deep knowledge base that could be built upon and extended. As a result, scholars began to expand the knowledge obtained during the classical period. As knowledge was expanded, the methods by which knowledge was obtained were reexamined and improved.

The scholars of the Islamic Golden Age introduced systematic experimentation as a method to find truth. Hypotheses were determined before experiments to prevent observational bias. Repetition of experiment was used with common sense selection of the best observed measured value in order to minimize instrumentation error. This systematic inductive procedure of experimentation, applicable to more problems than purely deductive reasoning, greatly expanded the breadth of scientific inquiry and discovery and laid the foundation of the modern scientific method.

In Part V we will see how a friar and some others brought the scientific method back to the West and built upon it.

Useful Links:

http://fourriverscharter.org/projects/Inventions/pages/muslimworld_algebra.htm
http://en.wikipedia.org/wiki/Islam_and_science
http://www.ms.uky.edu/~carl/ma330/project2/al-khwa21.html