INTRODUCING TAQl AL-DIN B. MA'RUF'S THE NATURE OF LIGHT ...

Muslim Education Quarterly. Vol. 22. No. 3 & 4, 2005
The Islamic Academy, Cambridge, U.K.
INTRODUCING TAQl AL-DIN B. MA'RUF'S THE
NATURE OF LIGHT AND THE FORMATION OF VISION
Hüseyin Gazi Topdemir
Introduction
My chief objective in this article is to introduce in detail the basic ideas expressed in
Taqi al-Din ibn Ma'ruf's Kitabu Nur-i Hadaka el-Ebsar and Nur-i HadTka el-Enzar
(henceforth Kitabu Nur) which has been neglected by the historians of science. Taqi
al-Din was a very productive scholar and one of the most mature scientists of his age.
For instance, he founded Istanbul Observatory in 1577 and compiled his observation
data in Sidra el-Muntaha al-Afkarfi Malakut Falak al-Davvar.
Taqi al-Din b. Ma'ruf was born around 1521 CE in Damascus and was an
eminent astronomer, physician and mathematician. Though we have generally very
limited information about the lives of the old Turkish scientists, we know the life of
Taqi al-Din b. Ma'ruf in detail. 1 Taqi al-Din has written about thirty books on
mathematics, physics, astronomy and automatons.
It is highly probable that Taqi al-Din's optics book was unique and the most
comprehensive work that was written in the sixteenth century in the Ottoman Empire.
Though there are a number of books explaining the formation of the rainbow and the
halo, none of them contains exhaustive information concerning the principles of
optics. 2 Taqi al-Din collected the results of prior successful investigations made in the
eleventh century which is known as the Classical Period of Islam, and transferred
these to the academic circles of his age. As it is generally accepted Avicenna and Ibn
al-Haytham were two pioneering figures for the establishment of optics as a science
in the Islamic World. 3 Besides his adoption of Avicenna and Ibn al-Haytham, Taqi al-
Dln's second main source was Kamal al-Din al-Farisi's Tanqih al-Manazir. 4 Since
there had been no attempt to clarify the value of the book and to determine to what
extent it has spread out yet, as a result of some partial studies on the different parts
of the book it seems that Tanqih al-Manazir whose title means the corrections of the
optics, was the most significant work in the Islamic World ever since the publication
of Kitab al-Manazir. Taqi al-Din's Kitabu Nur was not only the collection of the
optical information of the Classical Period of Islam, but at the same time, it contains
the results of the new experimental and theoretical studies of its writer. 5
1. The Copies of Kitabu Nur
There are four different copies of Taqi al-Din b. Ma'ruf's Kitabu Nur. One of them
is at the Süleymaniye Library, Laleli Collections, number 2558 in Istanbul. This copy
consists of 72 folios. Each folio contains 27 lines. In its introduction it is expressed

66 Muslim Education Quarterly
that this edition of Kitabu Nur was dedicated to al-Kerim ibn al-Kerim ibn al-Kerim
Molla Celebi Efendi Abd al-Kerim. It is not clear who edited this version.
Another copy is recorded at Oxford, Bodleian Library, Marsh 119. This copy of
Kitabu Nur has the dimensions of 25.9 cm x 17.4 cm, and contains a total of 83 folios.
In its introduction, it is stated that this copy is dedicated to Sultan Murad Han III. In the
last paragraph of the last folio of this copy of Kitabu Nur is recorded Taqi al-Din b.
Maruf 's long identity as Taqi al-Din Muhammad ibn Zain al-Din, the glory of sect and
religion and the last of the investigators, Ma'ruf ibn al-Shaikh Shihab al-Din Ahmad ibn
Muhammad ibn Muhammad ibn Ahmad ibn Yusuf ibn Ahmad ibn al-Amir Nasr al-
Din Menkubers ibn al-Amir Naskh al-Din Khumar Takin al-Arin, the prince of virility.
The third copy is also Mehmet Nuri Efendi Collection, number 163/3, at
Süleymaniye Library, in Istanbul, Turkey. The fourth copy is the section of Riyaza,
number 893, at Dar al-Kutub, in Cairo, Egypt.
2. The Analysis of Kitabu Nur
Apart from the "Introduction" (in Arabic, Muqaddimah), the book has three main
parts or books (in Arabic Mir sad). The introductory part draws a historical
background to the subject. The topic of the first part is the direct vision; the reflection
is the second part; and the refraction is the third part. In the first part Taqi al-Din
explains the nature of the relation between light and vision; in the second part the
changes of light on a mirror and the relation between reflected light and vision are
described. The third part is about the changes of light in different media and about the
differences emerging in vision resulting from those changes.
Taqi Aldan investigates the formation of vision, the cone of vision and the
source and target of light in the "Introduction", so that he can easily compare different
views on these matters in the history of optics. He groups these views under two main
camps, i.e. Aristotelians and Platonists. Though they have different explanations for
the source and target of the cone of vision, both the camps, for Taqi al-Din, are in line
with the fact that vision is formed by means of a cone. 6 Since the results of the
historical research on optics have shown that these two camps were dominant until
the eleventh century, and things changed for the Aristotelians only after Ibn al-
Haytham's studies, his explanations seem fully correct.
The first part of Kitabu Nur, which is about the direct vision, consists of six
chapters:
1. Inquiry into the Properties of Direct Vision
2. Inquiry into the Properties of Lights and into the Manner of Radiation of
Lights
3. The Effect of Light upon Sight
4. The Structure of the Eye
5. The Formation and the Nature of Vision
6. The Causes of Errors of Sight
In the first part we observe that Taqi Aldan regards the source of light as the object
itself. After this right contention he puts his main arguments, which were epochmaking
in optics, that light diffuses spherically along linear directions. 7 This
explanation is important in the sense that it makes an early reference to the wave

Introducing Taqi al-Din b. Ma 'ruf's The Nature of Light 67
model of light before that of Huygens.
The second part of Kitabu Nur, which is related to the reflection, consists of
six chapters:
1. Inquiry into the Properties of Reflected Lights
2. Inquiry into the Properties of Reflection
3. Inquiry into the Properties of Reflective Objects
4. On the Formation of Images by Reflection
5. On the Properties of Images by Reflection
6. On the Causes of Errors of Images by Reflection
In this part, Taqi al-Din explains the changes of light on a mirror and the formation
of vision on different mirrors. It is highly difficult to propose that Taqi al-Din
expressed original views concerning reflection, because the nature of reflection was
explained and properly exemplified in ancient times and there was hardly anything
left to be contributed to this particular field of optics.
The third part of Kitabu Nur, which is about refraction, consists of five
chapters:
1. Inquiry into the Properties of Refracted Lights
2. Inquiry into the Properties of Refraction
3. On the Formation of Images by Refraction
4. On the Ratio of Refraction Angels
5. On the Properties of Images by Refraction and On the Causes of Errors of
Images by Refraction
Taqi Aldan, in this part, examines the changes of light regarding its diffusion within
different media with different densities. In this part he made his important
contribution to optics by advocating a quite different approach to the law of refraction.
He expressed the issue not trigonometrically but geometrically by defining the law
of sine as an inequality between angles. 8 This chapter also includes a sub-section that
concentrates on the variations that light are subject to in the atmosphere. According
to Taqi al-Din, the same refraction rules, as in other media, are valid in the
atmosphere. A source of light, for example, the sun, emits rays of light directly in
space, as far as the density of the medium remains unchanged. When these light rays
reach the atmosphere, they are subject to refraction because of a change in density. 9
After the successful application of the principle of refraction to the
atmospheric refraction, in this book of Kitabu Nur, Taqi Aldan mentions an
instrument which clearly shows objects, which are distant from an observer. He
argues:
I made an instrument (billur), which is similar to the one that Greek
scientists had made [beforehand] and placed on the Tower of
Alexandria, displaying in detail the objects which are not visible to the
naked eye because of their distance, and through looking from one of
its edges one can see the sails of the ships at an average distance. 10

68 Muslim Education Quarterly
According to our exegetical analysis of Taqi al-Din's explanations, it seems that he
claims to have invented a kind of telescope. This instrument helps to see an object in
detail by bringing its image very close to the observer. In addition, Taqi al-Din stated
that he had written an article explaining the way of making and using this instrument.
According to known sources, the invention of telescope goes back to end of the 15th
century. It was in 1609 CE that Galileo directed his telescope to the sky and tried to
solve the mysteries of the universe. Taqi al-Din's book had been written nearly 30-
35 years before Galileo's invention. Therefore, it could be argued that Taqi al-Din
invented the telescope before Galileo. This is supported by the fact that none of the
known historical sources mention that there was an instrument like this before. Yet,
there is still confusion emerging from Taqi al-Din's own writing that his instrument
had similar properties to that of an instrument made by ancient Greeks.
3. Conclusion
In the light of all the explanations above, Taqi al-Din's book could be considered as
an invaluable optical book with respect to the way of treating optical problems, their
analysis and its level of optical knowledge in the 16th century. In addition, in order
for a good evaluation of the History of Science in the Ottoman Empire it is a
fundamental source to refer to.
Accordingly, through this book we get some crucial clues about the general
structure and the content of scientific works in the Ottoman Empire, and more
specifically, we unfold the nature of the continuation and the value of the studies
initiated by Ibn al-Haytham and developed by Kamal al-Din al-Farisi.
Taqi al-Din was not the founder of the science of optics in the Ottoman
Empire, but his Kitabu Nur culminates in the classical theories of optics in an
exhaustive manner. Taqi al-Din changed and re-organized the contemporary
knowledge of optics decisively, and he symbolizes for us a turning point in the
understanding of the scientific world of the Ottomans.
Notes
1. Ünver,A. Süheyl, Istanbul Rasathanesi, Ankara 1985, pp. 3-6; Adivar,A.Adnan, Osmanh
Türklerinde İlim, Istanbul 1982, pp. 100-109; Şeşen, Ramazan, "Meşhur Osmanlı
Astronomu Takiyüddin el-Rasid'ın Soyu Üzerine", Erdem, Vol. 4, Number 10,1988, pp.
165-171; Dizer, Muammer, Takiyüddin, Ankara, 1990, pp. 24-34.
2. Topdemir, Hüseyin Gazi, "Osmanlılarda Fizik Calışmaları", Osmanlı, Volume 8, 1999,
pp. 445-460.
3. Sabra, A.I, "Ibn al-Haytham", Dictionary of Scientific Biography, Volume 6, New York,
1972, pp. 189-210; Winter, H.J.J., "The Optical Researches of ibn al-Haitham",
Centaurus, Volume 3, 1954, pp. 190-210; Topdemir, Hüseyin Gazi, "Ibn el Heysem'in
Optik Araştırmaları", Bilim ve Felsefe Metinleri, Volume 1, Number 1, 1992, pp. 67-84;
Lindberg, David C, Theories of Vision, from al-Kindi to Kepler, Chicago 1976, pp. 58-
86; Rashed, Roshdi, "A Polymath in the 10th Century", Science, Volume 297, 2002, p.
773.
4. Taqi al-Din, Kitabu Nur, Muqaddima, O. folio no: 2b-3a; S. folio no: 2a-b.
5. Topdemir, Hüseyin Gazi, Takiyiüddin'in Optik Kitabi,(Taqi al-Din's Optics Book), Ankara

Introducing Taqi al-Din b. Ma 'ruf's The Nature of Light 69
1999.
6. Taqi al-Din, Kitabu Nur, Muqaddima, 0. folio no: 3a-3b; S. folio no: 2b.
7. Taqi al-Din, Kitabu Nur, Mirsad I, O, folio no: 7a; S, folio no: 6a-6b.
8. Taqi al-Din, Kitabu Nur, Mirsad III, O, folio no: 62a-b; S, folio no: 55b-56a.
9. Taqi al-Din, Kitabu Nur, Mirsad III, O, folio no: from 76b to79a; S, folio no: 68a-b.
10. Taqi al-Din, Kitabu Nur, Mirsad III, O. folio no: 81b; S. folio no: 72a.
Bibliography
Adivar, A. Adnan, Osmanlı Türklerinde İlim, Istanbul 1982.
Dizer, Muammer, Takiyüddin, Ankara, 1990.
Lindberg, David C, Theories of Vision, from al-Kindi to Kepler, Chicago 1976.
Rashed, Roshdi, "A Polymath in the 10th Century", Science, Volume 297,2002.
Sabra, A.I., "Ibn al-Haytham", Dictionary of Scientific Biography, Volume 6, New York 1972.
Şeşen, Ramazan, "Meşhur Osmanlı Astronomu Takiyüddin el-Rasid'ın Soyu Üzerine", Erdem,
Vol. 4, Number 10,1988.
Topdemir, Hüseyin Gazi, Takiyüddin'in Optik Kitabi, (Taqi al-Dln's Optics Book), Ankara
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Topdemir, Hüseyin Gazi, "Ibn el Heysem'in Optik Araştırmaları", Bilim ve Felsefe Metinleri,
Volume 1, Number 1,1992.
Ünver,A. Süheyl, Istanbul Rasathanesi, Ankara 1985.
Winter, H. J. J., "The Optical Researches of ibn al-Haitham", Centaurus, Volume 3,1954.