Avicenna begins The Canon with a
definition of the science of medicine: Medicine (tibb) is the science by
which we learn the various states of the human body in health and when not
in health, and the means by which health is likely to be lost, and when
lost, is likely to be restored. In other words, medicine is the art
whereby health is conserved and the art whereby it is restored after being
Avicenna insists that the human body cannot be restored to health
unless the causes of both health and disease are determined. In
categorising the causes, he states that a complete knowledge may be, and
should be obtained of the causes and antecedents of a disease, provided,
of course, such causes exist. Sometimes these causes are obvious to the
senses but at other times they may defy direct observation. In such
circumstances, causes and antecedents have to be carefully inferred from
the signs and symptoms of the disease. Hence, a description of the signs
and symptoms of disease is also necessary.
There are four causes: material, efficient, formal and final:
The Material Causes.
cause (maddi) is the physical body which is subject to health and disease.
This may be immediate and involve the organs of the body together with
their vital energies, or remote as involving the humors, or remoter than
these, by involving the elements which are the basis for both structure
and change (or dynamicity). Things which thus provide the foundation of
health and disease, get so thoroughly altered and integrated that from an
initial diversity there emerges a holistic unity with a specific structure
and a specific type of temperament.
The material cause then, is the
physical body, as viewed from the traditional perspective. It consists of
the organs, the vital energy (thymos), the humors and the elements.
constituents of the human body are "the elements." They are the basic
building blocks for the science of medicine.
The four elements - Earth,
Air, Fire and Water - are the simplest building blocks of all that is
material, including our bodies. Each of these has two qualities: Earth is
dry and cold; Water, cold and moist; Air, hot and moist; and Fire is hot
The elements also have special relationships to each other: Earth
is contrary to Air and Water to Fire. Union between the elements is
possible because Water serves as a link between Earth and Air and Air as a
link between Water and Fire.
The elements, like musical tones, possess an
inclination not only to ascend and descend, but also to move in a circular
direction. Each element is joined by one of its qualities to that which is
below and by the other to that which is above it.
Water to Earth beneath
by coldness and to Air above by moisture; Air to Water beneath by moisture
and to Fire above by heat; Fire to Air beneath by heat and to Earth toward
which it declines by dryness; Earth to Water above by coldness and to Fire
towards which it declines by dryness.
Two of the elemental qualities are
active and two passive. Active are hot and cold. Passive are dry and wet.
An ideal combination of elements exists when each one is on an equitable
basis with the other.
Quality results from the opposing qualities of
the elements, a mixture of hot, cold, wet and dry. Balance comes when the
strength of primary qualities are equal and represent an average of these
qualities. In medicine, balance does not depend upon the qualities and
elements being exactly equal, but upon them being "equitable," meaning
that the quality and quantity of the elements are distributed in such a
manner that the resulting pattern or equilibrium of the body as a whole or
of its parts is the one most appropriate for that person.
proportion in which the elements are united with the body has an influence
upon action. Slow and heavy movement signifies a predominance of cold and
dryness (Earth); fearfulness and sluggishness, of cold and wetness
(Water); cheerfulness, of heat and wetness (Air); and sharp, angry
violence, of heat and dryness (Fire).
All living beings consist of
elemental qualities which are interwoven into their physical process. If
something changes at an elemental level, something must have changed in
the physical process. The two stand to each other in the strict
relationship of cause and effect.
The phenomena of the external world
and, in traditional medicine, the inner world, also consist of the
elements and their qualities. Different elemental qualities are always
based on the different properties of the elements (higher, lower, lighter,
heavier, colder, hotter, etc.). The distinguishing characteristic of the
elements is that they differ like two colours, red and green, and like two
shades of a single colour, light and dark blue or like the shapes rough
and square. The properties of the elements distinguish them from one
another and at the same time orders them in definite ways.
quality of the elements is that they have direction. The elements attract
and in turn are attracted and are therefore directional forces. Elemental
motion has its origin not in their different properties but in differences
of dynamic quality as conveyors of motion.
The humors are the
vital essences of the body. These humors affect the function of the body
and are themselves influenced by physical functions.
Food and drink are
transformed into innate heat through the digestive process. The humors
arise in the second stage of digestion in the liver. This process produces
four humors which sustain and nourish the body and move through the
channels or meridians: sanguineous (blood), serous (phlegm), bilious
(choler, yellow bile) and atrabilious (melancholy, black bile); which
correspond respectively to Air (hot and moist), Water (cold and moist),
Fire (hot and dry) and Earth (cold and dry). The humors are subject to
variation in quantity and to variation in degree of purity.
results when there is either a quantitative or qualitative change of a
humor. In a "normal" state, the humors are assimilated by the organs and
completely integrated into the tissues. In an "abnormal" state, which is
due to improper digestion, the material is unsuitable for assimilation and
must therefore be eliminated by the body. Surpluses may be eliminated by
exercise, bathing, coitus, purges and laxatives.
- The sanguineous humor (blood), which is of a balanced nature, is hot
and moist, sweet and red, and exceeds the other humors in proportion to
quantity. It imparts strength and colour to the body and engenders the
drives. Located in the heart, it relates to the Zodiacal constellations
of Leo, Aries and Sagittarius.
- The phlegm humor or serous humor, is next to blood as far as the relative
quantity present in the body is concerned. This humor is watery, cold,
moist and white and moderates the strength, heat and thickness of the
blood, nourishes the brain, and moistens and nourishes the moving
parts of the body. If an abnormality of blood arises, heat will dissolve
the phlegm humor into blood. Cancer, Pisces and Scorpio are the Zodiacal
signs relating to this humor.
- The bilious humor, is less plentiful in the body than either blood
or phlegm. Its quantity is hot and dry, yellow or red and bitter. A part
of it passes from the liver to the gallbladder and another part flows
from the liver with other humors. This humor moderates moisture and
provides a penetrating quality to the blood so that it may enter more
readily into every tissue of the body. The bilious humor prevents the
body from becoming heavy, sleepy and dull. It penetrates and opens
passages and sustains those components of the body in which the fiery
element predominates. Zodiacal signs of the bilious humor are Gemini,
Aquarius and Libra.
- The atrabilious humorís quality is earthy and gross, thick, black
and sour. A part of it is separated out by the spleen and a part remains
within the blood. This humor feeds the bones, the spleen and other parts
of the body which are gross or "melancholy" in nature. It tempers the
two hot humors (sanguineous and bilious) and restrains the vaporous
volatiles that arise from blood. The atrabilious humor thickens the
blood and thus prevents it from flowing too freely through the veins and
arteries. The Zodiacal relationship of this humor is with Taurus, Virgo
Variability of the Humors.
humors vary considerably as regards their quantity and quality.
sanguineous rules from 3 am to 9 am; the bilious from 9 am to 3 pm; the
phlegm humor from 3 pm to 9 pm and the atrabilious humor from 9 pm to 3
am. The sanguineous humor increases in spring. The heat of summer opens
the pores, dissolves excess humors and reduces them, and causes the vital
breath to escape from the body when exhaling, together with moisture and
vapours. During this time, the bilious humor is dominant. Autumn tends to
generate the phlegm humor. During winter the humors thicken, the sinews
are contracted and the natural heat is directed inward. The atrabilious
humor increases and makes people sluggish.
The activity of the
elemental qualities (cold and heat) tends to determine which type of
humors are most likely to form. When the amount of heat present is in
balance, the sanguineous humor will be formed; when heat is in excess, the
bilious humor forms; when there is such an excess of heat that oxidation
occurs, the atrabilious humor forms. When the amount of cold present is
balanced, the phlegm humor forms; when there is an excessive amount of
cold, congelation becomes dominant and the atrabilious humor forms.
predominance of a given humor in the human body provides specific
characteristics of physique and behaviour.
Those dominated by
the sanguinious humor are cheerful, courageous, kind and ingenious. Their
blood, if of good quality, gives them a keen wit.
As a person
accumulates fat, the amount of Phlegm present relative to blood,
increases. Domination of the phlegm humor is present in people who are
generally lazy, given to pleasure, and who are sleepy, idle, dull witted,
heavy and slow. They love rich foods and drink.
Those with a
predominance of the bilious humor are easily provoked, given to treachery
and vehement in action; fierce when attacking, but inconstant in
maintaining the assault; inclined to envy, pride, extravagance and
vindictiveness. If there is corruption of the bilious humor, they
tend to be subject to abnormal desires and terrible nightmares.
dominated by the atrabilious humor are difficult, obstinate, suspicious,
sorrowful and given to terrifying impulses.
The natural predominance of
a given humor in the human body provides specific characteristics of
physique and behaviour.
The Psychic Faculties.
three faculties (Avicenna: souls) within man, the vegetable, animal and
rational. All of which fulfil their own functions. The more refined the
mixture of the humors, the greater is the perfection of the faculties and
the more complete the integration of the soul.Health means the harmony and
total balance of the humors (eucrasia - Classical Greek.), while illness
represents a disruption of the normal balance of the constitution.
course there is never perfect harmony, as living things are always
in a state of dynamic equilibrium in which one state of imbalance
counteracts another state of imbalance; therefore health means the re-
establishment of the balance of the humors relative to an individualís own
constitution and environment. Diagnosis for such disorders as fever are,
in fact, based on searching in order to discover in which way the humors
have become unbalanced. In diseases that are associated with clear
symptoms, diagnosis is made from the most notable sign or signs of the
disease, and a disease will often receive its name from the main signs
associated with it.
The Vital Force.
force (breath - Avicenna, pneuma or thymos - Classical Greek.) acts as
the link between the body, soul and spirit. It is the role of the vital
force to maintain a perfect equilibrium within the elements of the body,
and between the elements of the body and the environment.
The left side
of the heart is hollow in order to serve both as a storehouse of the vital
force, as well as the place of manufacture of the vital force. The vital
force in turn enables the soul to be convey its directions to the body and
its components. In the first place the vital force is a
rallying-point for the vital faculties (of the soul), and in the
second place it is an emanation that penetrates every tissue of the
The vital force is generated from the more refined aspects of the
humors and out of vital heat, while the tissues themselves are produced
from the coarser and earthy aspects of these humors. In other words,
the vital force is related to the refined particles as the body is related
to the coarser particles of the same humors.
There are three aspects or
spirits to the vital force, the natural spirit, the animal spirit and the
vital spirit. Each of these three aspects has its own place and function
and each has its own particular temperament.
Although the body consists
of several organs, there is one from which they all originally arose. As
to what this organ actually was, there are various opinions. The fact
remains that one organ necessarily came to light before other organs could
arise out of it. Exactly the same is true in the case of the vital force,
there is one single vital force that accounts for the origin of the other
vital energies. This vital force, according to the most important
philosophers, arises in the heart, passes thence into the principal
centers of the body, lingering in them long enough to enable them to
impart to it their respective temperamental properties. While it remains
in the cerebrum it receives a temperament that enables it to respond to
the impulses of sensation and movement; in the liver, it receives the
drive of nutrition and growth (vegetative drives); in the generative
glands it acquires a temperament that enables it to respond to the impulse
of generation (reproduction).
Thus the vital force has three components:
- The vital spirit, which is hot and dry, has its centre in the left
ventricle of the heart, preserves life, causes the body to grow, move
and reproduce, and travels through the arteries.
- The psychic spirit, which is cold and moist, has its centre in the
brain, causes sensation and movement, travels through the nerves and is
the source of movement and reason.
- The natural spirit, which is hot and moist, has its centre in the
liver, is concerned with the reception of food, growth and reproduction
and travels through the veins.
The humors are the
constituent elements from which the organs of the body are formed,
just as the humors are derived primarily from the intercombination
of nutrients and the nutrients are primarily composed of a combination
The organs are divided into two types: simple organs, which
have homogeneous parts such as flesh, bones and nerves, and compound
organs such as the hands and face. The organs are the servants of the mind
and are the instruments by the which the mind can control the body.
primary elemental quality of an organ is based on its nutrient while its
secondary quality is determined by what it excretes.
- Hot organs consist of vital force; blood; and tissues of the
heart, liver, flesh, muscle, spleen, kidneys, breasts, testicles,
muscular coats of arteries, veins, and of skin of the palm.
organs consist of phlegm; and tissues such as hair, bones,
cartilage, ligaments, serous membranes, nerves, spinal cord, brain,
solid and liquid fats and skin.
- Moist organs consist of
phlegm; blood; and tissues such as sold and liquid fats, brain, spinal
cord, breast, testicles, lungs, liver, spleen, kidneys, muscles and
- Dry organs consist of tissues such as hair, bones,
cartilage, ligaments, tendons, membranes, arteries, veins, motor nerves,
heart, sensory nerves, and skin.
The Efficient Causes.
The efficient causes (failiya) are capable of either preventing or
inducing change in the human body. They may be external to the person or
be of internal origin. External causes are: age, sex, occupation,
residence and climate and other agents which effect the human body by
contact, whether contrary to nature or not. Internal causes are sleep and
wakefulness, evacuation of secretions and excretions, the changes at
different periods of life in occupation, habits and customs, ethnic group
The efficient causes are clear and vary with each
individual. Whereas the elements, humors, vital force and organs are all
inherent and from nature, the efficient causes are acquired and develop
out of the nurturing process.
The Formal Causes.
There are three
formal causes (suriyah): temperaments (mizajat), the faculties or drives
(qawa) which emerge from it, and the structure.
Temperament arises from
the elements and humors and it determines the way in which the individual
functions. Each kind of living creature, as well as every organ of the
body, has its own temperament which is perfectly suited to its own
functional requirement. Some are more hot, others more cold, others more
dry and others more moist.
The temperament is "equable" (balanced or in
eucrasia - Classical Greek) when the contrary qualities are in perfect
equilibrium, and out of harmony or "inequable" when the temperament tends
toward a particular quality.
Therapeutics, then, are based on the
principle of providing treatments or medicines that have the opposite
quality to the excess of the imbalance. That is, "cold" diseases can be
cured by "hot" remedies and vice versa.
It is worth remembering that
when a medicine is referred to as being temperate (balanced - Avicenna),
it does not mean that its temperament is the same as of a human being, or
that it is even similar to it, for it would then be like a human being. It
merely means that such a medicine, after having been acted upon by the
innate heat [metabolised], fails to produce any material change in the
normal state of the body, and that its pharmacological actions remain
within the limits of the normal human temperament. In other words, when
this medicine is given to a normal person, it does not produce any
appreciable change or imbalance in the body.
When it is said that a
medicine is hot or cold, it does not mean that the physical quality of the
medicine is particularly hot or cold or that it is colder or hotter than
the human body. It just means that such a medicine, when ingested or
applied, produces a greater amount of heat or cold than what was
originally present in the body. A medicine which, for example, is cold for
a human being may be hot for a scorpion, while a medicine which is hot for
the human being may be cold for a serpent. In fact it may also mean that
the same medicine may be less hot for one person than for another. This is
the reason why physicians are advised to change their medicine when it
fails to produce the desired result.
The growth and decay of the human
body is dependent upon the human temperament. Growth depends upon the heat
contained in the inherent generative energy, which is gradually used up.
Meanwhile, the moisture lessens in quantity and quality, thus preserving
the innate heat at a constant level up to the old age. Ultimately,
however, the moisture of the body comes to an end, and the innate heat is
extinguished, thus causing the death to which everyone is destined and the
timing of which depends upon the original temperament of the human
The uniqueness of the temperament of each individual indicates
that each individual is a microcosm that represents a world of its own,
which is not identical with any other microcosm. Yet, the repetition of
the same basic humors in each constitution bears out the fact that each
microcosm presents a morphological resemblance to other
Moreover, there is an analogy between the human body and
the cosmic order, as shown by the correspondence between the humors and
elements. There is in the Hermetico-alchemical natural philosophy, which
has always been closely tied to Graeco-Arabic medicine, which represents a
basic doctrine of the correspondence between all the various orders of
reality: the intelligible hierarchy, the heavenly bodies, the order of
numbers, the parts of the body, the letters of the alphabet which are the
"elements" of the Sacred Book, etc. The seven cervical and the twelve
dorsal vertebrae correspond to the seven planets and the twelve signs of
the Zodiac, as well as to the days of the week and the months of the year;
and the total number of discs of the vertebrae, which are considered to be
twenty-eight, to the stations of the moon. There is, therefore, both
numerical and astrological symbolism connected with medicine.
these correspondences and "sympathy" (sympathia - Classical
various orders of cosmic reality, form the philosophical background of
The Vital Faculties.
also possesses vital faculties or drives, from which originate the
functions of various organs. The major faculties are:
- the vital faculty (hayawaniyah), which is responsible for preserving
the integrity of the vital force, sensation, and movement of the
- the natural faculty (tabiiyah), which governs the nutritive powers
of the liver and the reproductive powers of the generating organs;
- the animal faculty (nafsaniyah), which controls the brain and the
The ability of the different components of the body to function as one
entity arises from the vital faculty, which provides the body with its
inner force. The vital faculty is that which appears in the vital force at
the very moment at which the vital force develops out of the rarefied
particles of the humors.
There is a relationship between the human body
as a whole and its component parts; the whole being is active in any part
or components, while any part or component continually demonstrates its
relationship to the whole. Whenever we encounter a phenomenon that shows
this kind of relationship between its totality and its component parts, we
may assume that there is an ordered action of forces that underpins its
existence. This is the role of the faculties which we can only know
through their effects, as it works through the physical body without ever
being confined by it.
(Special note: according to some of Avicennaís other writings, the
faculties represent the natural laws inherent in the elements, humors and
in the vital force. In the true Hermetic tradition, Avicenna sees these
natural laws as embodying a component of Divine creative perfection, which
to him explains the tendency inherent in natural systems to direct
themselves towards a point of balance or equilibrium.- P.H.)
The Final Causes.
The final causes
(tamamia) are the actions or functions. They can only be understood from a
knowledge of both the faculties or drives (qawa) and the vital energies
(arwah) that are ultimately responsible for them.