Islamic Golden Age
postage stamp depicting al-Kindi
Birth c. 801
Early Islamic philosophy, Mu'tazili, Peripatetic school, Islamic
Main interests Astronomy Mathematics,
Medicine, Philosophy, Psychology, Science, Theology
Abū Yūsuf Yaaqūb
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(c. 801–873 CE), also known to the West by the Latinized version
of his name Alkindus, was an Arab polymath: an Islamic
philosopher, scientist, astrologer, astronomer, cosmologist,
chemist, logician, mathematician, musician, physician,
physicist, psychologist, and meteorologist. Al-Kindi was the
first of the Muslim Peripatetic philosophers, and is known for
his efforts to introduce Greek and Hellenistic philosophy to the
Arab world, and as a pioneer in chemistry, cryptography,
medicine, music theory, physics, psychology, and the philosophy
a descendant of the Kinda tribe. He was born and educated in
Kufa, before pursuing further studies in Baghdad. Al-Kindi
became a prominent figure in the House of Wisdom, and a number
of Abbasid Caliphs appointed him to oversee the translation of
Greek scientific and philosophical texts into the Arabic
language. This contact_us with "the philosophy of the ancients" (as
Greek and Hellenistic philosophy was often referred to by Muslim
scholars) had a profound effect on his intellectual development,
and lead him to write original treatises on subjects ranging
from Islamic ethics and metaphysics to Islamic mathematics and
mathematics, al-Kindi played an important role in introducing
Indian numerals to the Islamic and Christian world. He was a
pioneer in cryptanalysis and cryptology, and devised new methods
of breaking ciphers, including the frequency analysis method.
Using his mathematical and medical expertise, he developed a
scale to allow doctors to quantify the potency of their
medication. He also experimented with music therapy.
theme underpinning al-Kindi's philosophical writings is the
compatibility between philosophy and other orthodox Islamic
sciences, particularly theology. Many of his works deal with
subjects that concerned theology, including the nature of God,
the soul, and prophetic knowledge. However, despite the
important role he played in making philosophy accessible to
Muslim intellectuals, his own philosophical output was largely
overshadowed by that of al-Farabi and very few of his texts are
available for modern scholars to examine. However, he is still
considered one of the greatest philosophers of Arab descent, and
for this reason is known simply as "The Arab Philosopher".
2.1 Astrology, astronomy, and cosmology
2.2 Chemistry and perfumery
2.3 Cryptography and mathematics
2.4 Environmentalism and meteorology
2.6 Music theory
2.7 Philosophy and logic
2.8 Philosophy of science
3 Philosophical thought
3.4 The soul and the afterlife
3.5 The relationship between revelation and philosophy
4 Works translated into English
born in Kufa, Iraq to an aristocratic Kindah family, which had
migrated there from Yemen. His full name was, in
transliteration: Abū-Yūsuf Ya‘qūb ibn Isḥāq
ibn ‘Omrān ibn Isma‘īl al-Kindī; (in Arabic:
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His father was the governor of Kufa, and al-Kindi received his
preliminary education there. He later completed his studies in
Baghdad, where he was patronized by the Abbasid Caliphs
al-Ma'mun and al-Mu'tasim. Because of his learning and aptitude
for study, al-Ma'mun appointed him to House of Wisdom in
Baghdad, a recently established centre for the translation of
philosophical and scientific texts. He was well known for his
beautiful calligraphy, and at one point was employed as a
calligrapher by al-Mutawakkil.
al-Ma'mun died, his brother, al-Mu'tasim became Caliph.
Al-Kindi's position was enhanced under al-Mu'tasim, who
appointed him as a tutor to his son. But on the accession of
al-Wathiq, and especially of al-Mutawakkil, al-Kindi's star
waned. There are various theories why this happened: some
attribute al-Kindi's downfall to scholarly rivalries at the
House of Wisdom; others refer to al-Mutawakkil’s often violent
persecution of unorthodox Muslims (as well as of non-Muslims);
at one point al-Kindi was beaten and his library temporarily
confiscated. Al-Kindi died in Baghdad in 873, during the reign
of Al-Mu'tamid, "a lonely man".
death, al-Kindi's philosophical works quickly fell into
obscurity and many of them were lost even to later Islamic
scholars and historians. This may have occurred for a number of
reasons. Aside from the militant orthodoxy of al-Mutawakkil, the
Mongols destroyed countless libraries during their invasion.
However, the most probable cause was that his writings never
found popularity among influential philosophers such as
al-Farabi and Avicenna, who ultimately overshadowed him.
a master of many different areas of thought. Although he would
eventually be eclipsed by names such as al-Farabi and Avicenna,
he was held to be one of the greatest Islamic philosophers of
his time. The historian Ibn al-Nadim (d. 955), described him
The best man
of his time, unique in his knowledge of all the ancient
sciences. He is called the Philosopher of the Arabs. His books
deal with different sciences, such as logic, philosophy,
geometry, arithmetic, astronomy etc. We have connected him with
the natural philosophers because of his prominence in Science.
Renaissance scholar Geralomo Cardano (1501–1575) considered him
one of the twelve greatest minds of the Middle Ages.
According to Ibn al-Nadim, al-Kindi wrote at least two hundred
and sixty books, contributing heavily to geometry (thirty-two
books), medicine and philosophy (twenty-two books each), logic
(nine books), and physics (twelve books). His influence in
the fields of physics, mathematics, medicine, philosophy and
music were far-reaching and lasted for several centuries.
Although most of his books have been lost over the centuries, a
few have survived in the form of Latin translations by Gerard of
Cremona, and others have been rediscovered in Arabic
manuscripts; most importantly, twenty-four of his lost works
were located in the mid-twentieth century in a Turkish
library. The Theology of Aristotle, a paraphrase of parts of
Plotinus' Six Enneads along with Porphyry's commentary, seems to
have been edited by Al-Kindi.
astronomy, and cosmology
and astronomy, al-Kindi followed Ptolemy's view of the solar
system with the Earth at the centre of a series of concentric
spheres, in which the known heavenly bodies (the Moon, Mercury,
Venus, the Sun, Mars, Jupiter, and the stars) are embedded. In
one of his treatises on the subject, he says that these bodies
are rational entities, whose circular motion is in obedience to
and worship of God. Their role, al-Kindi believes, is to act as
instruments for divine providence. He furnishes empirical
evidence as proof for this assertion: different seasons are
marked by particular arrangements of the planets and stars (most
notably the sun), and (according to al-Kindi) the appearance and
manner of people varies according to the arrangement of heavenly
bodies situated above their homeland.
discussed the process by which the heavenly bodies affect the
material world. One theory he posits in his works is from
Aristotle, who conceived that the movement of these bodies
causes friction in the sub-lunar region, which stirs up the
primary elements of earth, fire, air and water, and these
combine to produce everything in the material world. An
alternative view found in his treatise On Rays is that the
planets exercise their influence in straight lines. In each of
these, he presents two fundamentally different views of physical
interaction; action by contact_us and action at a distance. This
dichotomy is duplicated in his writings on optics.
al-Kindi maintained the traditional Aristotelian view of gravity
according to which heavy bodies, such as the Earth, move
downward toward the centre and light bodies, such as Fire, move
upward away from the centre.
Chemistry and perfumery
advanced chemist, al-Kindi was the first to oppose the practice
of alchemy; he debunked the myth that simple, base metals could
be transformed into precious metals such as gold or silver.
He wrote two treatises on the refutation of alchemy: Warning
against the Deceptions of the Alchemists and Refutation of the
Claim of Those Who Claim the Artificial Fabrication of Gold and
the work of Jabir ibn Hayyan (Geber), the isolation of ethanol
(alcohol) as a relatively pure compound was first achieved by
al-Kindi. He was the first to unambiguously describe the
production of pure distilled alcohol from the distillation of
invented a wide variety of scent and perfume products, and is
considered the father of the perfume industry. He carried out
extensive research and experiments in combining various plants
and other sources to produce a variety of scent products. He
elaborated a vast number of recipes for a wide range of
perfumes, cosmetics and pharmaceuticals. His work in the
laboratory is reported by a witness who said, "I received the
following description, or recipe, from Abu Yusuf Ya'qub b. Ishaq
al-Kindi, and I saw him making it and giving it an addition in
my presence". The writer goes on in the same section to speak of
the preparation of a perfume called ghaliya, which contained
musk, amber and other ingredients, and reveals a long list of
technical names of drugs and apparatus.
Kimiya' al-'Itr (Book of the Chemistry of Perfume) written by
al-Kindi contains recipes for fragrant oils, salves, aromatic
waters, and substitutes or imitations of costly drugs. He also
provided the earliest recipe for the production of camphor.
page of al-Kindi's manuscript On Deciphering Cryptographic
Messages, containing the oldest known description of
cryptanalysis by frequency analysis.
Cryptography and mathematics
a pioneer in cryptography, especially cryptanalysis. He gave the
first known recorded explanation of cryptanalysis in A
Manuscript on Deciphering Cryptographic Messages. In particular,
he is credited with developing the frequency analysis method
whereby variations in the frequency of the occurrence of letters
could be analyzed and exploited to break ciphers (i.e.
cryptanalysis by frequency analysis). This was detailed in a
text recently rediscovered in the Ottoman archives in Istanbul,
A Manuscript on Deciphering Cryptographic Messages, which also
covers methods of cryptanalysis, encipherments, cryptanalysis of
certain encipherments, and statistical analysis of letters and
letter combinations in Arabic. Al-Kindi also had knowledge
of polyalphabetic ciphers centuries before Leon Battista
Alberti. Al-Kindi's book also introduced the classification of
ciphers, developed Arabic phonetics and syntax, and described
the use of several statistical techniques for cryptoanalysis.
This book apparently antedates other cryptology references by
several centuries, and it also predates writings on probability
and statistics by Pascal and Fermat by nearly eight
authored works on a number of other important mathematical
subjects, including arithmetic, geometry, the Indian numbers,
the harmony of numbers, lines and multiplication with numbers,
relative quantities, measuring proportion and time, and
numerical procedures and cancellation. He also wrote four
volumes, On the Use of the Indian Numerals (Ketab fi Isti'mal
al-'Adad al-Hindi) which contributed greatly to diffusion of the
Indian system of numeration in the Middle East and the West. In
geometry, among other works, he wrote on the theory of
parallels. Also related to geometry were two works on optics.
One of the ways in which he made use of mathematics as a
philosopher was to attempt to disprove the eternity of the world
by demonstrating that actual infinity is a mathematical and
Environmentalism and meteorology
known work concerned with environmentalism and pollution was an
Arabic medical treatise written by al-Kindi. His writings, along
with the works of his successors (Qusta ibn Luqa, Muhammad ibn
Zakarīya Rāzi, Ibn Al-Jazzar, al-Tamimi, al-Masihi, Avicenna,
Ali ibn Ridwan, Ibn Jumay, Isaac Israeli ben Solomon,
Abd-el-latif, Ibn al-Quff and Ibn al-Nafis), covered a number of
subjects related to pollution such as air contamination, water
contamination, soil contamination, solid waste mishandling, and
environmental assessments of certain localities.
wrote a treatise on meteorology entitled Risala fi l-Illa
al-Failali l-Madd wa l-Fazr (Treatise on the Efficient Cause of
the Flow and Ebb), in which he presents an argument on tides
which "depends on the changes which take place in bodies owing
to the rise and fall of temperature." He describes the
following clear and precise laboratory experiment in order to
prove his argument:
One can also
observe by the senses... how in consequence of extreme cold air
changes into water. To do this, one takes a glass bottle, fills
it completely with snow, and closes its end carefully. Then one
determines its weight by weighing. One places it in a
container... which has previously been weighed. On the surface
of the bottle the air changes into water, and appears upon it
like the drops on large porous pitchers, so that a considerable
amount of water gradually collects inside the container. One
then weighs the bottle, the water and the container, and finds
their weight greater than previously, which proves the change.
[...] Some foolish persons are of opinion that the snow exudes
through the glass. This is impossible. There is no process by
which water or snow can be made to pass through glass.
more than thirty treatises attributed to al-Kindi in the field
of medicine, in which he was partly influenced by the ideas of
Galen, and partly by his own personal experience and other
Muslim physicians in his time.
most important work in this field is probably De Gradibus, in
which he demonstrates the application of mathematics and
quantification to medicine, particularly in the field of
pharmacology. For example, he developed a mathematical scale to
quantify the strength of a drug and a system, based the phases
of the Moon, that would allow a doctor to determine in advance
the most critical days of a patient's illness.
Treatise on Diseases Caused by Phlegm, he provided the first
scientific explanation and treatment for epilepsy:
phlegm melts and changes to a bad irritant quality, it goes
forth and ascends to the brain from a certain direction, then it
sinks down through the principal veins towards the heart, and by
its irritant quality it deranges the place of sense, thought and
recollection in the brain. It passes through the veins towards
the heart, and if the natural heat whose source is the heart is
strong enough to dissolve it, it does so, and what happens as a
consequence is epilepsy (sar). For the parts of the brain which
we have mentioned, becoming injured, are overcome and cease to
function. The disturbance which we see in the (patient’s) body
is owing to the conflict of the natural (heat) with the
affection. When it prevails over it, it attacks and dissolves
it. This is the meaning of the foam which is seen at the
(patient’s) mouth. When this occurs, his recovery is near.
Aqrabadhin (Medical Formulary), he describes many pharmaceutical
preparations, including simple drugs derived mostly from
botanical sources as well as animal and mineral sources.
Kimiya' al-'Itr (Book of the Chemistry of Perfume) written by
al-Kindi contains recipes for salves and substitutes or
imitations of costly drugs.
the first great theoretician of music in the Arab-Islamic world.
He proposed adding a fifth string to the 'ud and discussed the
cosmological connotations of music. He surpassed the achievement
of the Greek musicians in using the alphabetical annotation for
one eighth. He published fifteen treatises on music theory, but
only five have survived. In one of his treaties the word musiqia
was used for the first time in Arabic, which today means music
in Arabic, Persian, Turkish, English and several other languages
in the Islamic world.
Philosophy and logic
contribution to the development of early Islamic philosophy was
his efforts to make Greek and Hellenistic thought both
accessible and acceptable to a Muslim audience. Al-Kindi carried
out this mission from the House of Wisdom, an institute of
translation and learning patronized by the Abbasid Caliphs, in
Baghdad. As well as translating many important texts, much
of what was to become standard Arabic philosophical vocabulary
originated with al-Kindi; indeed, if it had not been for him,
the work of philosophers like Al-Farabi, Avicenna, and
al-Ghazali might not have been possible.
writings, one of al-Kindi's central concerns was to demonstrate
the compatibility between philosophy and natural theology on the
one hand, and revealed or speculative theology on the other
(though in fact he rejected speculative theology). Despite this,
he did make clear that he believed revelation was a superior
source of knowledge to reason because it guaranteed matters of
faith that reason could not uncover. While his philosophical
approach was not always original, and was even considered clumsy
by later thinkers, he successfully incorporated Aristotelian and
neo-Platonist thought into an Islamic philosophical framework.
This was an important factor in the introduction and
popularization Greek philosophy in the Muslim intellectual
writers on logic in Islamic philosophy during the 8th and 9th
centuries produced commentaries on Aristotelian logic. The first
original Arabic writings on logic were produced by al-Kindi, who
produced a summary on earlier logic up to his time.
Philosophy of science
important contributions to the philosophy of science and the
development of scientific methodology. Like his Arab predecessor
Geber, al-Kindi placed a strong emphasis on experimentation, and
in addition, he introduced a new emphasis on quantification. He
also wrote the following on his view of scientific
We must not
hesitate to recognize the truth and to accept it no matter what
is its origin, no matter if it comes to us from the ancients or
from foreign people... My purpose is first to write down all
that the ancients have left us on a given topic and then, using
the Arabic tongue and taking into account the customs of our
time and our capacities, to complete what they have not fully
al-Kindi held ancient authorities (such as Aristotle) in high
regard, he often criticized them for making claims regarding
natural philosophy without providing any empirical proof, nor
any empirical evidence or scientific demonstration. In many
instances, al-Kindi used experiments and quantitative methods to
verify many of his own theories, as he recognized the importance
of direct observation and empiricism as a source of scientific
knowledge. He also often invented specific laboratory apparatus
in order to carry out his experiments.
theories of optics appear in the writings of al-Kindi;
Aristotelian and Euclidian. Aristotle had believed that in order
for the eye to perceive an object, both the eye and the object
must be in contact_us with a transparent medium (such as air) that
is filled with light. When these criteria are met, the "sensible
form" of the object is transmitted through the medium to the
eye. On the other hand, Euclid proposed that vision occurred in
straight lines when "rays" from the eye reached an illuminated
object and were reflected back. As with his theories on
Astrology, the dichotomy of contact_us and distance is present in
al-Kindi's writings on this subject as well.
which al-Kindi relied upon to determine which of these theories
was most correct was how adequately each one explained the
experience of seeing. For example, Aristotle's theory was unable
to account for why the angle at which an individual sees an
object affects his perception of it. For example, why a circle
viewed from the side will appear as a line. According to
Aristotle, the complete sensible form of a circle should be
transmitted to the eye and it should appear as a circle. On the
other hand, Euclidian optics provided a geometric model that was
able to account for this, as well as the length of shadows and
reflections in mirrors, because Euclid believed that the visual
"rays" could only travel in straight lines (something which is
commonly accepted in modern science). For this reason, al-Kindi
considered the latter preponderant.
In his Kitab
al-Shu'a'at (Book of the Rays), al-Kindi wrote the following
criticism on Anthemius of Tralles for reporting how "ships were
set aflame by burning mirrors during a naval battle" without
should not have accepted information without proof... He tells
how to construct a mirror from which twenty four rays are
reflected on a single point, without showing how to establish
where the rays unite at a given distance from the middle of the
mirror's surface. We, on the other hand, have described this
with as much evidence as our ability permits, furnishing what
was missing, for he has not mentioned a definite distance.
As an Islamic
psychologist, al-Kindi was a pioneer in experimental psychology.
He was the first to use the method of experiment in psychology,
which led to his discovery that sensation is proportionate to
the stimulus. He was also the earliest to realize the
therapeutic value of music and attempted to cure a quadriplegic
boy using music therapy.
He also dealt
with psychology in several other treatises: On Sleep and Dreams
(a treatise on dream interpretation), First Philosophy, and
Eradication of Sorrow. In the latter, he described sorrow as "a
spiritual (Nafsani) grief caused by loss of loved ones or
personal belongings, or by failure in obtaining what one lusts
after" and then added: "If causes of pain are discernible, the
cures can be found." He recommended that "if we do not tolerate
losing or dislike being deprived of what is dear to us, then we
should seek after riches in the world of the intellect. In it we
should treasure our precious and cherished gains where they can
never be dispossessed...for that which is owned by our senses
could easily be taken away from us." He also stated that "sorrow
is not within us we bring it upon ourselves." He developed
cognitive methods to combat depression and discussed the
intellectual operations of human beings.
intellectuals were already acquainted with Greek philosophy
(especially logic), al-Kindi is credited with being the first
real Muslim philosopher. His own thought was largely
influenced by the Neo-Platonic philosophy of Proclus, Plotinus
and John Philoponus, amongst others, although he does appear to
have borrowed ideas from other Hellenistic schools as well.
He makes many references to Aristotle in his writings, but these
are often unwittingly re-interpreted in a Neo-Platonic
framework. This trend is most obvious in areas such as
metaphysics and the nature of God as a causal entity.
Earlier experts had suggested that he was influenced by the
Mutazilite school of theology, because of the mutual concern
both he and they demonstrated for maintaining the pure unity
(tawhid) of God. However, such agreements are now considered
incidental, as further study has shown that they disagreed on a
number of equally important topics.
al-Kindi, the goal of metaphysics is the knowledge of God. For
this reason, he does make a clear distinction between philosophy
and theology, because he believes they are both concerned with
the same subject. Later philosophers, particularly al-Farabi and
Avicenna, would strongly disagree with him on this issue, by
saying that metaphysics is actually concerned with qua being,
and as such, the nature of God is purely incidental.
al-Kindi's understanding of metaphysics is God's absolute
oneness, which he considers an attribute uniquely associated
with God (and therefore not shared with anything else). By this
he means that while we may think of any existent thing as being
"one", it is in fact both "one" and many". For example, he says
that while a body is one, it is also composed of many different
parts. A person might say "I see an elephant", by which he means
"I see one elephant", but the term 'elephant' refers to a
species of animal that contains many. Therefore, only God is
absolutely one, both in being and in concept, lacking any
multiplicity whatsoever. This understanding entails a very
rigorous negative theology because it implies that any
description which can be predicated to anything else, cannot be
said about God.
to absolute oneness, al-Kindi also described God as the Creator.
This means that He acts as both a final and efficient cause.
Unlike later Muslim Neo-Platonic philosophers (who asserted that
the universe existed as a result of God's existence
"overflowing", which is a passive act), al-Kindi conceived of
God as an active agent. In fact, of God as the agent, because
all other intermediary agencies are contingent upon Him. The
key idea here is that God "acts" through created intermediaries,
which in turn "act" on one another - through a chain of cause
and effect - to produce the desired result. In reality, these
intermediary agents do not "act" at all, they are merely a
conduit for God's own action. This is especially significant
in the development of Islamic philosophy, as it portrayed the
"first cause" and "unmoved mover" of Aristotelian philosophy as
compatible with the concept of God according to Islamic
contrast to ancient Greek philosophers such as Aristotle who
believed that the universe had an infinite past with no
beginning, Al-Kindi believed that the universe has a finite past
with a beginning. This view was inspired by the creation
doctrine shared by the three Abrahamic religions: Judaism,
Christianity and Islam. The Christian philosopher, John
Philoponus, presented the first such argument against the
ancient Greek notion of an infinite past. However, the most
sophisticated medieval arguments against an infinite past were
developed by Al-Kindi, Saadia Gaon (Saadia ben Joseph) and
Al-Ghazali (Algazel). They developed two logical arguments
against an infinite past, the first being the "argument from the
impossibility of the existence of an actual infinite", which
infinite cannot exist."
temporal regress of events is an actual infinite."
An infinite temporal regress of events cannot exist."
argument, the "argument from the impossibility of completing an
actual infinite by successive addition", states:
infinite cannot be completed by successive addition."
series of past events has been completed by successive
The temporal series of past events cannot be an actual
arguments were adopted by later Christian philosophers and
theologians, and the second argument in particular became more
famous after it was adopted by Immanuel Kant in his thesis of
the first antimony concerning time.
philosophers such as Plato and Aristotle would
highly revered in the medieval Islamic world.
theorized that there was a separate, incorporeal and universal
intellect (known as the "First Intellect"). It was the first of
God's creation and the intermediary through which all other
things came into creation. Aside from its obvious metaphysical
importance, it was also crucial to al-Kindi's epistemology,
which was influenced by Platonic realism.
Plato, everything that exists in the material world corresponds
to certain universal forms in the heavenly realm. These forms
are really abstract concepts such as a species, quality or
relation, which apply to all physical objects and beings. For
example, a red apple has the quality of "redness" derived from
the appropriate universal. However, al-Kindi says that human
intellects are only potentially able to comprehend these. This
potential is actualized by the First Intellect, which is
perpetually thinking about all of the universals. He argues that
the external agency of this intellect is necessary by saying
that human beings cannot arrive at a universal concept merely
through perception. In other words, an intellect cannot
understand the species of a thing simply by examining one or
more of its instances. According to him, this will only yield an
inferior "sensible form", and not the universal form which we
desire. The universal form can only be attained through
contemplation and actualization by the First Intellect.
he provides to explain his theory is that of wood and fire.
Wood, he argues, is potentially hot (just as a human is
potentially thinking about a universal), and therefore requires
something else which is already hot (such as fire) to actualize
this. This means that for the human intellect to think about
something, the First Intellect must already be thinking about
it. Therefore he says that the First Intellect must always be
thinking about everything. Once the human intellect comprehends
a universal by this process, it becomes part of the individual's
"acquired intellect" and can be thought about whenever he or she
The soul and the afterlife
believed that the soul is a simple, immaterial substance, which
is related to the material world only because of its faculties
which operate through the physical body. To explain the nature
of our worldly existence, he (borrowing from Epictetus) compares
it to a ship which has, during the course of its ocean voyage,
temporarily anchored itself at an island and allowed its
passengers to disembark. The implicit warning is that those
passengers who linger too long on the island may be left behind
when the ship sets sail again. Here, al-Kindi displays a stoic
concept, that we must not become attached to material things
(represented by the island), as they will invariably be taken
away from us (when the ship sets sail again). He then connects
this with a Neo-Platonist idea, by saying that our soul can be
directed towards the pursuit of desire or the pursuit of
intellect; the former will tie it to the body, so that when the
body dies, it will also die, but the latter will free it from
the body and allow it to survive "in the light of the Creator"
in a realm of pure intelligence.
in this phenomenal world is transitory; it is a journey towards
the eternal one. The most miserable man, is he who prefers for
himself the material above the spiritual, for the material,
apart from its ephemeral nature, obstructs our passage to the
spiritual world. Man should not `disregard any means to protect
himself against all human vices, and he should seek to rise to
the highest ends of human virtues..., that is, to the knowledge
by means of which we protect ourselves against spiritual and
bodily disease, and acquire the human virtues in whose very
essence goodness is grounded.
The relationship between revelation and philosophy
In the view
of al-Kindi, prophecy and philosophy were two different routes
to arrive at the truth. He contrasts the two positions in four
ways. Firstly, while a person must undergo a long period of
training and study to become a philosopher, prophecy is bestowed
upon someone by God. Secondly, the philosopher must arrive at
the truth by his own devices (and with great difficulty),
whereas the prophet has the truth revealed to him by God.
Thirdly, the understanding of the prophet - being divinely
revealed - is clearer and more comprehensive than that of the
philosopher. Fourthly, the way in which the prophet is able to
express this understanding to the ordinary people is superior.
Therefore al-Kindi says the prophet is superior in two fields:
the ease and certainty with which he receives the truth, and the
way in which he presents it. However, the crucial implication is
that the content of the prophet's and the philosopher's
knowledge is the same. This, says Adamson, demonstrates how
limited the superiority al-Kindi afforded to prophecy
to this, al-Kindi adopted a naturalistic view of prophetic
visions. He argued that, through the faculty of "imagination" as
conceived of in Aristotelian philosophy, certain "pure" and
well-prepared souls, were able to receive information about
future events. Significantly, he does not attribute such visions
or dreams to revelation from God, but instead explains that
imagination enables human beings to receive the "form" of
something without needing to perceive the physical entity to
which it refers. Therefore, it would seem to imply that anyone
who has purified themselves would be able to receive such
visions. It is precisely this idea, amongst other naturalistic
explanations of prophetic miracles that al-Ghazali attacks in
his Incoherence of the Philosophers.
al-Kindi appreciated the usefulness of philosophy in answering
questions of a religious nature, there were many Islamic
thinkers who were not as enthusiastic about the use of
philosophy. However, it would be incorrect to assume that they
opposed philosophy simply because it was a "foreign science".
Oliver Leaman, an expert on Islamic philosophy, points out that
the objections of notable theologians are rarely directed at
philosophy itself, but rather at the conclusions the
philosophers arrived at. Even al-Ghazali (famous for his
critique of the philosophers, The Incoherence of the
Philosophers), was himself an expert in philosophy and logic.
Al-Ghazali's criticized the philosophers not for their methods,
but for arriving at theologically erroneous conclusions. The
three most serious of these, in his view, were believing in the
co-eternity of the universe with God, denying the bodily
resurrection, and asserting that God only has knowledge of
abstract universals, not of particular things.
life, al-Kindi was fortunate enough to enjoy the patronage of
the pro-Mutazilite Caliphs al-Ma'mun and al-Mu'tasim, which
meant he could carry out his philosophical speculations with
relative ease. This would change significantly towards the end
of his life when al-Mutawakkil supported the traditionalists,
and initiated persecution of various unorthodox schools of
thought, including the philosophers. In his own time, al-Kindi
would be criticized for extolling the "intellect" as being the
most immanent creation in proximity to God, a standing commonly
held to be the position only of the angels. He also engaged
in disputations with the Mutazilites, whom he attacked for their
belief in atoms. But the real role of al-Kindi in the
conflict between philosophers and theologians would be to
prepare the ground for debate. His works, says Deborah Black,
contained all the seeds of future controversy that would be
fully realized in al-Ghazali's book, Incoherence of the
Works translated into English
The Medical Formulary of Aqra¯ba¯dhı¯n of Al-Kindi by M Levey
Al-Kindi's Metaphysics: A Translation of Yaqub ibn Ishaq
al-Kindi's Treatise "On First Philosophy" (Fi al-Falsafah
al-Ula) by Alfred L. Ivry (1974)
Scientific Weather Forecasting in the Middle Ages The Writings
of Al-Kindi by Gerrit Bos and Charles Burnett (2000)
al-Kindi’s Treatise on Cryptanalysis by M. Mrayati, Y. Meer Alam
and M. H. at Tayyan (2003)
^ "Stanford Encyclopedia of Philosophy: Al-Kindi". Stanford
Encyclopedia of Philosophy. Stanford University (2006-12-1).
Retrieved on 2008-08-24.
^ a b c d e f g h i "Al-Kindi". FSTC Limited. Retrieved on
^ Klein-Frank, F. Al-Kindi. In Leaman, O &
Nasr, H (2001). History of Islamic Philosophy. London:
Routledge. p 165
^ Corbin, H. (1993). History of Islamic Philosophy. London:
Keagan Paul International. p154
^ Adamson 2005, P. 'Al-Kindi'. In Adamson, P & Taylor, R.
(2005). The Cambridge Companion to Arabic Philosophy. Cambridge:
Cambridge University Press. p 33
^ "Abu Yusuf Yaqub ibn Ishaq al-Sabbah Al-Kindi" (HTML).
Retrieved on 2007-01-12.
^ Simon Singh. The Code Book. p. 14-20
^ Klein-Franke, p172
^ a b c Saoud, R.. "The Arab Contribution to the Music of the
Western World" (PDF). FSTC. Retrieved on 2007-01-12.
^ Adamson, p34
^ a b c Corbin, p154
^ Corbin, p154
^ Klein-Franke, p166
^ "Al-Kindi, Encyclopaedic Scholar of the Baghdad 'House of
Wisdom'" (HTML). Retrieved on 2007-01-12.
^ George Satron. Introduction to the History of Science.
^ Corbin, pp 154–155
^ Klein-Franke, pp 172–173
^ Adamson, Peter (2002), "Before Essence and Existence:
al-Kindi's Conception of Being", Journal of the History of
Philosophy 40(3): 297-312,
on 21 August 2008
^ Adamson 2005, p.42
^ Adamson 2005, p.43
^ George N. Atiyeh, Al-Kindi: Philosopher of the Arabs,
(Rawalpinidi: Islamic Research Institute, 1966), p. 85
^ Klein-Franke, p174
^ a b c Plinio Prioreschi, "Al-Kindi, A Precursor Of The
Scientific Revolution", Journal of the International Society for
the History of Islamic Medicine, 2002 (2): 17-19 .
^ Hassan, Ahmad Y. "Alcohol and the Distillation of Wine in
Arabic Sources". History of Science and Technology in Islam.
Retrieved on 2008-03-29.
^ Simon Singh. The Code Book. p. 14-20
^ "Al-Kindi, Cryptgraphy, Codebreaking and Ciphers" (HTML).
Retrieved on 2007-01-12.
^ Ibrahim A. Al-Kadi (April 1992), "The origins of cryptology:
The Arab contributions”, Cryptologia 16 (2): 97–126
^ "Abu Yusuf Yaqub ibn Ishaq al-Sabbah Al-Kindi" (HTML).
Retrieved on 2007-01-12.
^ Al-Allaf, M. "Al-Kindi's Mathematical Metaphysics" (PDF).
Retrieved on 2007-01-12.
^ L. Gari (2002), "Arabic Treatises on Environmental Pollution
up to the End of the Thirteenth Century", Environment and
History 8 (4), pp. 475-488.
^ P. Prioreschi. Al-Kindi, A Precursor of the Scientific
^ Klein-Franke, p. 172
^ Plinio Prioreschi, "Al-Kindi, A Precursor Of The Scientific
Revolution", Journal of the International Society for the
History of Islamic Medicine, 2002 (2): 17-19 [17-18].
^ Plinio Prioreschi, "Al-Kindi, A Precursor Of The Scientific
Revolution", Journal of the International Society for the
History of Islamic Medicine, 2002 (2): 17-19 .
^ Adamson 2005, pp 32–33
^ Klein-Franke, pp 166–167
^ Randall R. Dipert. "History of logic". Encyclopædia
Britannica. Retrieved on 2008-08-21.
^ Adamson 2005, p45
^ Iqbal, Muhammad, "The Spirit of Muslim Culture", The
Reconstruction of Religious Thought in Islam,
Retrieved on 25 January 2008
^ Haque, Amber (2004), "Psychology from Islamic Perspective:
Contributions of Early Muslim Scholars and Challenges to
Contemporary Muslim Psychologists", Journal of Religion and
Health 43(4): 357-377 
^ Klein-Frank, p 165
^ Adamson 2005, p37
^ a b Adamson, p36
^ a b Corbin, p155
^ Adamson 2005, p34
^ Adamson 2005, p35
^ Klein-Frank, p167
^ Adamson 2005, p39
^ a b c Craig, William Lane (June 1979), "Whitrow and Popper on
the Impossibility of an Infinite Past", The British Journal for
the Philosophy of Science 30(2): 165-170 [165-6]
^ Klein-Frank, p168
^ Adamson 2005, p40-41
^ Adamson 2005, p40
^ Adamson 2005, p41-42
^ Adamson 2005, p46-47
^ Corbin, p156
^ Adamson 2005, p47
^ Leaman, O. (1999). A Brief Introduction to Islamic Philosophy
Polity Press. p21.
^ Black, p168
^ Black, p169
^ Black, p171
Robert L. Arrington (2001) [ed.] A Companion to the
Philosophers. Oxford: Blackwell. ISBN 0-631-22967-1
Peter J. King (2004) One Hundred Philosophers. New York:
Barron's. ISBN 0-7641-2791-8
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Taylor (eds). The Cambridge Companion to Arabic Philosophy.
Cambridge: Cambridge University Press.
Peter Adamson (2006) Al-Kindi. Oxford: OUP.
Felix Klein-Frank (2001) Al-Kindi. In Oliver Leaman & Hossein
Nasr. History of Islamic Philosophy. London: Routledge.
Henry Corbin (1993). History of Islamic Philosophy. London:
Keagan Paul International.