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Abu Ali
al-Husain ibn Abdallah - Ibn Sina
(Avicenna)
Born: 980 in Kharmaithen (near
Bukhara), Central Asia (now Uzbekistan)
Died: June 1037 in Hamadan, Persia (now Iran)
Ibn Sina is often known by
his Latin name of Avicenna, although most references to him
today have reverted to using the correct version of ibn Sina. We know many details of his
life for he wrote an autobiography which has been supplemented with material from a
biography written by one of his students. The autobiography is not simply an account of
his life, but rather it is written to illustrate his ideas of reaching the ultimate truth,
so it must be carefully interpreted. A useful critical edition of this autobiography
appears in [7] while a new translation appears in [9].
The course of ibn Sina's life was dominated by the
period of great political instability through which he lived. The Samanid dynasty, the
first native dynasty to arise in Iran after the Muslim Arab conquest, controlled
Transoxania and Khorasan from about 900. Bukhara was their capital and it, together with
Samarkand, were the cultural centres of the empire. However, from the middle of the 10th
century, the power of the Samanid's began to weaken. By the time ibn Sina was born, Nuh
ibn Mansur was the Sultan in Bukhara but he was struggling to retain control of the
empire.
Ibn Sina's father was the governor of a village in one
of Nuh ibn Mansur's estates. He was educated by his father, whose home was a meeting place
for men of learning in the area. Certainly ibn Sina was a remarkable child, with a memory
and an ability to learn which amazed the scholars who met in his father's home. By the age
of ten he had memorised the Qur`an and most of the Arabic poetry which he had read. When
ibn Sina reached the age of thirteen he began to study medicine and he had mastered that
subject by the age of sixteen when he began to treat patients. He also studied logic and metaphysics, receiving instruction from some of the
best teachers of his day, but in all areas he continued his studies on his own. In his
autobiography (see [7] or [9]) ibn Sina stresses that he was more or less self-taught but
that at crucial times in his life he received help.
It was his skill in medicine that was to prove of great
value to ibn Sina for it was through his reputation in that area that the Samanid ruler
Nuh ibn Mansur came to hear of him. After ibn Sina had cured the Samanid ruler of an
illness, as a reward, he was allowed to use the Royal Library of the Samanids which proved
important for ibn Sina's development in the whole range of scholarship.
If the fortunes of the Samanid rulers had taken a turn
for the better, ibn Sina's life would have been very different. Nuh ibn Mansur, in an
attempt to keep in power, had put Sebüktigin, a former Turkish slave, as the ruler of
Ghazna and appointed his son Mahmud as governor of Khorasan. However the Turkish
Qarakhanids, already in control of most of Transoxania, joined with Mahmud and moved to
depose the Samanids. After gaining Khorasan they took Bukhara in 999. There followed a
period of five years in which the Samanids tried to regain control but their period of
power was over. As recounted in [2]:-
Destiny had plunged [ibn Sina] into one of the
tumultuous periods of Iranian history, when new Turkish elements were replacing Iranian
domination in Central Asia and local Iranian dynasties were trying to gain political
independence from the 'Abbasid caliphate in Baghdad (in modern Iraq).
The defeat of the Samanids and another traumatic event,
the death of his father, changed ibn Sina's life completely. Without the support of a
patron or his father, he began a life of wandering round different towns of Khorasan,
acting as a physician and administrator by day while every evening he gathered students
round him for philosophical and scientific discussion. He served as a jurist in Gurganj,
was in Khwarazm, then was a teacher in Gurgan and next an administrator in Rayy. Perhaps
most remarkable is the fact that he continued to produce top quality scholarship despite
his chaotic life style. For [2]:-
... the power of concentration and the intellectual
prowess of [ibn Sina] was such that he was able to continue his intellectual work with
remarkable consistency and continuity and was not at all influenced by the outward
disturbances.
After this period of wandering, ibn Sina went to Hamadan
in west-central Iran. Here he settled for a while becoming court physician. The ruling
Buyid prince, Shams ad-Dawlah, twice appointed him vizier. Politics was not easy at that
time and ibn Sina was forced into hiding for a while by his political opponents and he
also spent some time as a political prisoner in prison [26]
... but he escaped to Isafan, disguised as a Sufi, and
joined Ala al-Dwla.
Ibn Sina's two most important works are The Book of
Healing and The Canon of Medicine. The first is a scientific encyclopaedia covering logic,
natural sciences, psychology, geometry, astronomy, arithmetic and music. The second is the
most famous single book in the history of medicine. These works were begun while he was in
Hamadan.
After being imprisoned, ibn Sina decided to leave
Hamadan in 1022 on the death of the Buyid prince who he was serving, and he travelled to
Isfahan. Here he entered the court of the local prince and spent the last years of his
life in comparative peace. At Isfahan he completed his major works begun at Hamadan and
also wrote many other works on philosophy, medicine and the Arabic language.
During military campaigns ibn Sina was expected to
accompany his patron and many of his works were composed on such campaigns. It was on one
such military campaign that he took ill and, despite attempting to apply his medical
skills to himself, died [1]:-
... of a mysterious illness, apparently a colic that was
badly treated; he may, however, have been poisoned by one of his servants.
Ibn Sina's wrote about 450 works, of which around 240
have survived. Of the surviving works, 150 are on philosophy while 40 are devoted to
medicine, the two fields in which he contributed most. He also wrote on psychology,
geology, mathematics, astronomy, and logic. His most important work as far as mathematics
is concerned, however, is his immense encyclopaedic work, the Kitab al-Shifa' (The Book of
Healing). One of the four parts of this work is devoted to mathematics and ibn Sina
includes astronomy and music as branches of mathematics within the encyclopaedia. In fact
he divided mathematics into four branches, geometry, astronomy, arithmetic, and music, and
he then subdivided each of these topics. Geometry he subdivided into geodesy, statics,
kinematics, hydrostatics, and optics; astronomy he subdivided into astronomical and
geographical tables, and the calendar; arithmetic he subdivided into algebra, and Indian
addition and subtraction; music he subdivided into musical instruments.
The geometric section of the encyclopaedia
is, not surprisingly, based on Euclid's Elements. Ibn Sina gives proofs but the
presentation lacks the rigour adopted by Euclid. In fact ibn Sina does not present
geometry as a deductive system from axioms in this work. We should note, however, that
this was the way that ibn Sina chose to present the topic in the encyclopaedia. In other
writings on geometry he, like many Muslim scientists, attempted to give a proof of
Euclid's fifth postulate. The topics dealt with in the geometry section of the
encyclopaedia are: lines, angles, and planes; parallels; triangles; constructions with ruler and compass; areas of parallelograms and
triangles; geometric algebra; properties of circles; proportions without mentioning irrational numbers; proportions relating to areas of
polygons; areas of circles; regular polygons; and volumes of polyhedra and the sphere.
Full details are given in [17].
Ibn Sina made astronomical observations and we know that
some were made at Isfahan and some at Hamadan. He made several correct deductions from his
observations. For example he observed Venus as a spot against the surface of the Sun and
correctly deduced that Venus must be closer to the Earth than the Sun. This observation,
and other related work by ibn Sina, is discussed in [53]. Ibn Sina invented an instrument
for observing the coordinates of a star. The instrument had two legs pivoted at one end;
the lower leg rotated about a horizontal protractor, thus showing the azimuth, while the upper leg marked with a scale and
having observing sights, was raised in the plane vertical to the lower leg to give the
star's altitude. Another of ibn Sina's contributions to astronomy was his attempt to
calculate the difference in longitude between Baghdad and Gurgan by observing a meridian transit of the moon at Gurgan. He also correctly
stated, with what justification it is hard to see, that the velocity of light is finite.
As ibn Sina considered music as one of the branches of
mathematics it is fitting to give a brief indication of his work on this topic which was
mainly on tonic intervals, rhythmic patterns, and musical instruments. Some experts claim
that ibn Sina's promotion of the consonance of the major third led to the use of just
intonation rather than the intonation associated with Pythagoras. More information is
contained in T S Vyzgo's paper "On Ibn Sina's contribution to musicology" in
[5].
Mechanics was a topic which ibn Sina classified under
mathematics. In his work Mi`yar al-`aqul ibn Sina defines simple machines and combinations
of them which involve rollers, levers, windlasses, pulleys, and many others. Although the
material was well-known and certainly not original, nevertheless ibn Sina's classification
of mechanisms, which goes beyond that of Heron, is highly original.
Since ibn Sina's major contributions are in philosophy,
we should at least mention his work in this area, although we shall certainly not devote
the space to it that this work deserves. He discussed reason and reality, claiming that
God is pure intellect and that knowledge consists of the mind grasping the intelligible.
To grasp the intelligible both reason and logic are required. But, claims ibn Sina [26]:-
... it is important to gain knowledge. Grasp of the
intelligibles determines the fate of the rational soul in the hereafter, and therefore is
crucial to human activity.
Ibn Sina gives a theory of knowledge, describing the
abstraction in perceiving an object rather than the concrete form of the object itself. In
metaphysics ibn Sina examined existence. He considers the scientific and mathematical
theory of the world and ultimate causation by God. His aims are described in [1] as
follows:-
Ibn Sina sought to integrate all aspects of science and
religion in a grand metaphysical vision. With this vision he attempted to explain the
formation of the universe as well as to elucidate the problems of evil, prayer,
providence, prophecies, miracles, and marvels. also within its scope fall problems
relating to the organisation of the state in accord with religious law and the question of
the ultimate destiny of man.
Ibn Sina is known to have corresponded with al-Biruni.
In [10], eighteen letters which ibn Sina sent to al-Biruni in answer to questions that he
had posed are given. These letters cover topics such as philosophy, astronomy and physics.
There is other correspondence from ibn Sina which has been preserved which has been
surveyed in the article [31]. The topics of these letters include arguments against
theologians and those professing magical powers, and refutation of the opinions those who
having a superficial interest in a branch of knowledge. Ibn Sina writes on certain topics
in philosophy, and writes letters to students who must have asked him to explain
difficulties they have encountered in some classic text. The authors of [31] see ibn Sina
as promoting natural science and arguing against religious men who attempt to obscure the
truth.
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