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by copyright: Antoine
Danchin © & Disclaimer.
These pages represent a biased choice of
dates relevant to biology, obtained by compiling a great many
different sources, often using the original texts and not the
WWW; the information collected here does not use Wikipedia
which, by construction, relies on a process akin to a vote, and
changes over time in order to reflect some kind of a popular
anonymous consensus about knowledge. Care
has been taken to check information and rewrite it when needed; direct
access links to the original sources is provided whenever possible;
however date records still contain many errors; the links are
chosen to be as diverse as possible, they do not engage the responsability
of the author. Note however that many WWW links are generally
unstable, so that many might be obsolete despite regular checks.
Note that the links
in French and in English may differ. Notez que les liens en
Français et en Anglais sont souvent différents.
Please send comments and corrections here.
Back in time, and in civilisations other
than the one located in Greece, it is difficult to collect appropriate
information about what science, and especially biology was. Astronomy
and Medicine were practiced everywhere in the world, associated
to religious or ethical behaviour and practices. It is therefore
impossible to draw a specific line between what became science
and what were other social practices. The choice presented here
is therefore the more biased the more we go back in time. And
we shall certainly amend our presentation as time elapses. This
page is therefore to be considered as under permanent (re)construction.
It is however quite certain that Science had something to do
with the transformation of Myths and Epics into a formalized
representation of the world. The people lacking such organized
view of their origins would not, therefore, easily accept science
when it came and were not prone to develop it.
It is most likely that modern Homo sapiens born 200,000
thousand years ago, somewhere in Eastern (Central) Africa, came
out of that continent, through Ethiopia and Southern Egypt, then
to Mesopotamia, while migrating eastward at the rather fast speed
of about fourty kilometers per century. Western Asia was invaded
first, with a very old human branch going southwards as far as
Australia at a time when glaciations lowered considerably the
Ocean level. It seems now likely that there has been several
waves of migration, with local speciation and mixing. It now
seems that Homo sapiens sapiens mated with Homo
giving birth to Caucasians and Asians, and a second time with Homo
sapiens neanderthalensis Denisova, to give birth to Melanesians.
Appropriate selective mutations, in particular of the skin's
pigmentation, hair production and nose shape had to appear to
create human types more adapted to the local environmental conditions.
In particular a light skin complexion was probably needed to
catch more sun light, and thus prevent rachitism when Man migrated
northward. In the same way, body hair, which had disappeared
earlier, perhaps as a beneficial trait against body parasites,
sometimes reappeared with the selection pressure imposed by low
temperature in northern parts of the world. The neolithic revolution
appeared subsequently some 12,000 years ago. The earliest home
of human written civilisation is now generally supposed to have
been Sumer, with another root in Egypt shortly after the Neolithic
revolution began. The Chinese written civilisation goes way back
in time (several thousand years after Sumer and Egypt however,
consistent with the usual speed of human migration), and there
are most probably links between the former and the latter, through
the West-East link which had to go through the mountains of what
is now Afghanistan and the Xinjiang desert towards the centre
of China. In fact in more recent times this route was followed
by Alexander the
Great (356-323 BC), and there remains valleys in Afghanistan
where people still speak a Greek dialect.
In Egypt, was very early on (starting some 6,000 years ago
at least) developed an art of healing which was certainly based
not merely on superstition (and in particular on superstition
associated to natural numbers, small integers) but also upon
actual observation. Despite its extreme importance for the creation
of knowledge, the contribution of ancient Egypt has usually been
overlooked. Many reasons may account for this, but it is most
likely the development of the three major monotheistic religions
which played the most significant role in what must be considered
as a blind spot or even as a purposedly organized censorship
of the Egyptian thought. One can indeed trace back in history
many of the actual texts found in the hebraïc Bible (and
subsequent christian and islamic derivatives) in Egyptian beliefs
and texts. And of course, religions which state that God reavealed
Himself through talking to prophets can hardly accept that the
content of God's revelation can be deeply rooted in history...
Pharao Amenophis IV, who made himself known as Akhenaton (~1380
- 1337 BC), created a remarkable monotheistic religion which
is likely to be concomitant with and probably predates Moses
travels and sayings. But neither the Israelite Hebrews, who had
to fly away from Egypt, taking the new religion with them (they
would fuse it with the other manichean, babylonian creeds when
in Palestine, hence the two tales of Genesis in the first part
of the Bible), nor the Christians, nor, finally, the Muslims
which now occupy Egypt (the Christian Copts are probably much
nearer the Truth of their fathers than any other religion) could
easily accept that their beliefs have a concrete, factual, history.
High level theologies accept this type of situation, but their
teaching is not spread as a common cultural background... And
it goes without saying that because a significant part of Egypt
was of black complexion and clearly descending from central Africa,
there was and still is a strong reluctance to accept that major
human advances could have come from people with a black skin.
The same is true when we witness the interesting resistance of
many people (especially in Asia) to accept that modern Man is
an ... African.
Sumerians, Egyptians, Babylonians, followed by Indians and
Chinese succeeded in collecting a considerable mass of individual
facts, sometimes extremely astute, which were organised along
the local religious or ethical creeds. Then, about 2,500 years
ago, with the creation of the Presocratic
philosophy in Greece, science was born, with an entirely
new and original way to organise human knowledge.
It is very important to be able to distinguish between religion
and philosophy. Philosophy has many meanings, but it contains
one central point: it is thinking about thinking. Religion is
mostly organized around a reflection about Life and above all,
Death, and it is associated to practices involving the behaviour
of Man facing Death, the only hard fact everyone has to face.
This explains why there may be certain contradictions when people
mix up Philosophy and Religion. For example, in China, Daoism
can be either a Philosophy, or a Religion. As a Philosophy (dao
jia 道 家), the Dao, the Way, encourages people to follow Nature,
as a Religion (dao jiao 道教), it is a set of practices against
Nature, trying to avoid Death. Of course a philosophy is underlying
any type of religion, but a religion implies a social structure,
rites and beliefs organised in a socio-political way. Similarly,
philosophy is concerned by the question of life and death, but,
by construction, philosophy questions the world (including beliefs),
while religion, with its social structure and rites, answers
questions, from all eternity.
Science, the daughter and extension of philosophy, is organized
exploration. That it has been created
by Greek philosophers, travelling from island to island,
from Western Asia to Sicily, is no chance. It is not the place
here to discuss geographic, economic and socio-political reasons
underlying the birth of Science, but the quasi-absence of China
from the scene is no chance despite its extremely old and involved
aptitude in developing new techniques. Probably through interactions
with the Greek world, science certainly started to develop in
China and India (this can be seen in old mathematics treaties).
However, China, geographically, politically, and economically
emphasizes stability, not questioning or exchanging. This explains
why science was uprooted there when it became to be visible.
The main social categories in China (scholars, farmers, artisans,
merchants, in that order of importance, the first three, associated
to production, making "the root"
and the last, associated to exchange, "the branch")
account for the sharp distinction between what is of nature and
what is of man, what is natural
and what is artificial, a distinction which is relevant to
today's reactions about genetically modified organisms, for example.
This being said, we can find dates where scientific facts,
questions and hypotheses were put forward and slowly organised
to yield present day science. We are interested here in biology,
which is science associated to agriculture and medicine. But
since science also means development of reasoning and development
of an experimental approach, the first dates with which we shall
be concerned will correspond to the creation of logics and the
creation of the first experiments.
Science needs stable transmission of knowledge. This requires
something more practical and less error prone than oral transmission.
We need therefore to retain as major dates those in which writing
was invented, then writing on supports that were easy to construct:
stone, clay tablets, papyrus and paper (later on, the skin of
animals). One must be very careful when interpreting later reconstructions
of ancient history: only actual texts and pictures in monuments
and other artefacts, which can be dated precisely, can give a
reliable evaluation of dates of inventions. It must be borne
in mind that all civilisations tend to self-appropriate the origin
of discoveries to their own people, without much control, and
in fact, it seems clear that the origin of most important early
discoveries were made in civilisations no longer extant, the
Sumerian and Egyptian civilisations. It must also be borne in
mind that Man was always mobile, with a speed of invasion rather
fast: well over one hundred kilometers per century after the
beginning of the Neolithic age, because of the help provided
by the domestication of animals, and the possibility to bring
seeds to provide food support. Hence many discoveries traveled
back and forth during the first millenia of the Neolithic age
in a way which is still very poorly documented.
~10000 BC The dog is domesticated in Mesopotamia.
The taming of animals and the cultivation of plants begins to
spread both eastwards and westwards at the speed of about 50-100
km per century.
~6000 BC Yeast is used by Sumerians to make
beer and wine. This practice slowly diffuses southwards, eastwards
and westwards. Process metallurgy begins as one of the oldest
sciences with the processing of gold.
~5000 BC The first cities are created in Mesopotamia.
The horse is domesticated in Ukraine. From this date onwards
diffusion of human knowledge becomes much faster, with the spread
of horses as a means of transport and communication.
~4200 BC Copper is discovered as a metal susceptible
to processing. It remains a symbol of the beginning of civilisation
in the middle East, and its name is associated to this region
(the symbol for copper is Cu and comes from the latin cuprum, meaning
from the island of Cyprus).
~4000 BC The Egyptians discover how to bake
leavened bread using yeast. Donkeys are domesticated. Communication
spreads fast along the Nile river benefiting from the opposition
between the stream of the Nile (which goes North) and the dominant
wind (going South). The Sumerians and the Egyptians discover
~3600 BC Copper alloys are used by Egyptians
and Sumerians. The first copper smelted artifacts are found in
the Nile valley: copper rings, bracelets, chisels; smelting of
gold and silver are known. Exchange with Africa through the Nile
valley brings minerals and metals to Egypt.
~3500 BC The Egyptians begin to write down
accounts of important royal events, first on stones, then on
wood. The Egyptians use galena (lead sulfides with a metallic
shine) as cosmetic for blackening features of the face.
~3400 BC The first symbols for numbers, simple
straight lines, corresponding to a decimal number counting system
(without the zero) appear to be in use in Egypt. The Egyptian
know how to extract the metal from copper ore.
~3300 BC Sumerian writing on clay tablets
becomes a common practice. The Minoan civilisation begins in
Crete, pervading all the Aegean sea.
~3250 BC The wheel is in use in Mesopotamia
~3000 BC Tooth filling is performed in Sumer.
The Sumerian writing evolves into cuneiform. The abacus is developed
in the Middle East and in areas around the Mediterranean. Hieroglyphic
numerals are in use in Egypt.
~3000 BC to 2500 BC Sumerian
medicine discovers the healing qualities of mineral springs.
The weaving loom is known in Europe.
~2800 BC Beginning of systematic astronomical
observations in Egypt, Babylonia, India, and China. Egypt introduces
a calendar of 365 days without adjustments.
~2750 BC The great wall of Uruk, with 900
towers, is built in Mesopotamia. The construction of Cheops Pyramid
conforms in layout and dimensions to astronomical measurements.
Sumerians begin to use a sexagesimal number system for recording
financial transactions. It is a place-value system without a
zero place value. This is the probable date of manufacture of
the first iron objects, but iron smelting is not yet practical.
Iron processing will be exported to the East and North-West following
human migrations, while being continuously improved.
~2500 BC Egyptian carvings depict existing
techniques of surgery. In Egypt, papyrus, the first attempt to
use a convenient light support for writing, becomes a common
support. Another way to make vegetal paper was rediscovered in
China, with a more elaborate process, several thousand years
later and subsequently exported to Europe. Beginning of the historical
record of the Chinese civilisation.
~2100 BC The earliest known legal texts are
written by Ur-Nammu, king of Ur.
~2000 BC In Egypt, the ratio between the radius
of a circle and its circonference is measured as 3. This is later
on transmitted to the Hebrews and to the Greeks. The Egyptians
introduce a form of contraceptive. Egyptians use knotted rope
triangle with whole numbers (a2 + b2 =
c2: "Pythagoras" theorem) to construct right
angles. Harappans adopt a uniform decimal system of weights and
~1900 BC A papyrus written in Egypt (The Moscow
papyrus, also called the Golenishev papyrus) gives details of
Egyptian geometry. Four basic elements are known in India to
describe material objects: Earth, Air, Fire, and Water. The original
place of this description is not known (it could be as far away
as Egypt). It becomes the rational basis of the description of
all forms of matter throughout the Middle East for several millenia.
~1800 BC Babylonians use multiplication tables.
~1750 BC In Crete, Minos palace has light
and air shafts, bathrooms with water supply. Irrigation system
in Egypt systematically utilizes Nile floods. The Code of Hammurabi
(who founds Babylonia) includes guidelines for medical practices
(including eye surgery) and permissible fees. Babylonia uses
highly developed geometry as basis for astronomic measurements
and creates the signs of the zodiac. Tin is discovered and added
to copper in metal alloys. The Babylonians solve linear and quadratic
algebraic equations, compile tables of square and cube roots.
They use Pythagoras' theorem and use mathematics
to extend knowledge of astronomy.
~1700 BC The Rhind papyrus (sometimes called
the Ahmes papyrus) is written. It shows that Egyptian mathematics
has developed many techniques to solve problems. Multiplication
is based on repeated doubling, and division uses successive halving.
~1600 BC A decimal system appears to have
been in use in Crete (or, most likely, introduced from Egypt).
The highly evolved Minoan civilisation flourishes until it is
destroyed, perhaps after the explosion of the volcano in Santorini
which covered most of the region with ashes and sterilized everything
for more than a century. Mercury (Greek- ὑδραργυρος,
liquid silver; latin- argentum vivum, live or quick silver) is
stated to have been found in Egyptian tombs of this time.
~1550-1200 BC The Minoan civilisation develops
its own writing system. The Linear A script was a basis for the
development of the Linear B writing, which emerged here on Crete
in about 1450 BC and soon spread to continental Greece. Both
Linear B and Linear A were written during the 2nd millennium
BC in Minoan Crete. Michael Ventris deciphered Linear B in 1952.
This is the written syllabic language that spread from the Minoans
to the Myceneans. Linear A has not yet been deciphered. The influence
of this civilisation in Greece in terms of Science is therefore
~1500 BC The practice of iron smelting becomes
common in Syria and Palestine. During the Shang 商朝 period
(1700 BC-1027 BC) appear the first Chinese pictograms engraved
on bones. Medicinal bloodletting has been practiced since the
Stone Age. Almost every ancient and modern culture has drawn
blood to cure disease. Early cultures believed that illness was
caused by evil spirits and that these could be removed by withdrawing
blood from the patient. A way to control blood letting is to
use animals: the earliest known illustration of the use of leeches
for medicinal purposes is a painting in an Egyptian tomb. The
sundial is used in Egypt to measure the time of day by the sun's
shadow. Hours are shorter in winter and longer in summer.
~1400 BC An intricate clock, measuring flow
of water, deposited in the tomb of Amenophis III demonstrates
domination of first experimental science by Egyptians. The remains
of glass furnaces discovered by Flinders-Petrie at Tel-El-Amarna
in Egypt illustrate the manufacture of rods, beads, and jars
or other figures, formed apparently by covering clay cores with
glass and later removing the cores.
~1300 BC Mathematical permutations and "magic
squares" are known of Chinese mathematicians. A decimal
number system with no zero starts to be used in China. The properties
of the Pythagorean triangle become known. Using these properties
the height of sun in relation to the incline of polar axis is
measured in China.
~1100 BC First proven domestication of the
silkworm in China (said to have existed well before that date,
but not proven, sure to have existed after 500 BC). Advanced
knowledge of shipbuilding is developed in Mediterranean and Scandinavian
countries, with concomitant exploration of far regions of the
World by sea. The Egyptians make models of Anubis, one of the
Gods of Deads, with a mobile jaw, meant to simulate speech. These
are the first ancestors of modern robots simulating life.
~1000 BC Chinese use counting boards (abacus)
~950 BC "Biotechnology" extends
away from the simple agro-food processes or from medicine: fabric
dyes are made from purple snails and staining with alum practiced
in Mediterranean area. The Indian lunar year has 360 days adjusted
at random to coincide with solar year. A Chinese textbook of
mathematics includes planimetry, proportions, "rule of 3" arithmetic,
root multiplication, geometry, equations with one and more unknown
quantities, and a theory of motion. Earliest use of iron smelting
in Greece. Chaldeans use water-filled cube for measuring time,
weight, and length.
841 BC Beginning of the verified Chinese historical
~800 BC Baudhayana is the
author of one of the earliest of the Indian Sulbasutras (texts
about mathematical problems). The Chinese begin to use iron,
after smelting is slowly introduced from the West. Medicine becomes
divorced from priesthood and medical training in India uses anatomical
models. In Greece, Homer refers to highly developed battlefield
surgery. Sledges with rollers are in use for heavy loads. Assyrians
use animal bladders as swimming aids in warfare.
763 BC King Adadnirari 11 of Assyria starts
a new chronology (verified in connection with solar eclipse of
June 15 of that year).
~750 BC Manava writes a Sulbasutra.
Manava's Sulbasutra, like all the Sulbasutras, contains approximate
constructions of circles from rectangles, and squares from circles,
which can be thought of as giving approximate values of π.
There appear therefore different values of π throughout
the Sulbasutra, essentially every construction involving circles
leads to a different such approximation. An interpretation of
verses 11.14 and 11.15 of Manava's work gives π =
25/8 = 3.125. Babylonian and Chinese astronomy understands planetary
movements; the Babylonian new calendar is confirmed. Spoked wheels
and horseshoes are in use in Europe.
~650 BC King Assurbanipal's famous library,
with over 22,000 clay tablets, covers history, medicine, astronomy,
astrology. The movement of planets and signs of zodiac are recorded
in Assyria, where water clocks are constrructed. King Sermacherib's
garden in Nineveh palace has rare plants and animals; planting
space and irrigation channels are blasted from rock, allowing
improvement in plant breeding and a beginning of hygiene. Progress
in water installations; Jerusalem has subterranean water tunnels;
Sermacherib builds an aqueduct; Nineveh has bucket wells. Kaleos
is the first to sail through the Straits of Gibraltar (Pillars
of Hercules). Glaucos of Chios invents the soldering of iron.
Pharaoh Nechos of Egypt (reigned 609-593) starts
a canal between the Nile and the Red Sea. He also orders the
first reliably recorded circumnavigation of Africa by Phoenicians.
~600 BC Apastamba writes the most interesting
Indian Sulbasutra from a mathematical point of view. In India,
our present decimal-positional method of writing numbers originates.
It took a long time for this mathematical system to make its
way to the Mediterranean/European area and to be accepted. It
took an even longer time to be accepted in China. Witnessing
the archaic system still used for measuring weight and distances
in America today, it is easily understood that very primitive
ideas can have a long life. The decimal system became common
after the Islamic arithmetic was developed.
~590 BC Thales (Milet,
625 - 547) choses the Ocean as the primitive element. He knows
that a magnet attracts iron and that amber, when rubbed, becomes
magnetic. He brings Babylonian mathematical knowledge to Greece.
He uses geometry to solve problems such as calculating the height
of pyramids and the distance of ships from the shore. The "Thales
Proposition" (triangles over the diameter of a circle are
right-angled) is oldest theory of occidental mathematics. A water
system is built by Eupalinos, on the island
of Samos, a three-quarter-mile-long tunnel started simultaneously
at both ends. Priscus builds the first Roman stone bridge. Nebuchadnezzar
11 builds a palace with terrace gardens in Babylon (presumed
to be the legendary "Hanging Gardens," one of seven
wonders of the world); a tunnel more than half a mile long, connecting
the palace and the Temple of the Sun, traverses the Euphrates
below the river bed. Theodoros of Samos is credited
with invention of iron casting, water level, lock and key, carpenter's
square, and shaping clay by wheeling. The Roman lunar year has
10 months of varying lengths (later 12 months). Babylonian astronomy
begins to conform to present reckonings; the lunar year has 354
days regulated into 12 months alternating between 29 and 30 days.
~580 BC Anaximander (Milet,
611 - 547) choses the illimited (Απειρον)
as the primitive element. He also draws the first map (on papyrus).
He is credited with the first written work on natural science,
a classical poem entitled Περι φυσεως (On
Nature). In this poem, he states that human beings must descend
from aquatic animals, presenting what may be the first written
theory of evolution, stating that in the beginning there was
a fish-like creature with scales that arose in and lived in the
world ocean. As some of these advanced, they moved onto land,
shed their scaly coverings, and became the first humans.
~550 BC Anaximenes (Milet,
585 - 528) emphasizes the processes of condensation and rarefaction
needed to create all extant forms, including living organisms.
~540 BC Sushrata teaches
medicine at the University of Benares about surgery, obstetrics,
diet, bathing, drugs, infant feeding and hygiene, and medical
~540 BC Xenophanes (Colophon,
570 - 475) can be said to have been the first to formalize the
hypothetical nature of what we now know as Science, differentiating
between the World and its truth (αληθεια)
and Models of the World (δοξα). Xenophanes is
one of the first people to write about his observations of fossils,
thinking that fossils were an indication that there was water/mud
previously in an area. Counting rods are used in China.
~530 BC Pythagoras (Samos,
560 - ~480) moves to Crotone in southern Italy and teaches mathematics,
geometry, music, and reincarnation. His world is based of the
organisation of Monads: the integers. A link is made between
the alphabet and the whole numbers. In fact this is what prevented
the discovery of the concept of zero, discovered later in India. Zeno (Elee
~570 - ?) emphasizes the question posed by the contradiction
between the continuous and the discontinuous.
~510 BC Heraclitus (Ephese
540 - 475) places emphasis on Change as the principal cause of
~500 BC Human cadavers are dissected for scientific
study by the Greek physician Alcmaeon (Crotone,
535 - ?) who discovers what we know name the Eustachian tubes
in the ear. He states that good health results between the equilibirum
of powers similar to those described by Anaximenes 'humidity/dryness'
'cold/heat' 'bitterness and sweetness', while disequilibrium
causes diseases. He also discovers the difference between veins
and arteries, as well as the connection between brain and sensory
organs. In India, Panini's work on Sanskrit
grammar is the forerunner of the modern formal language theory.
The first known cataract operation is performed by Sushrata in
India (Susrata Samhita). The Babylonian sexagesimal number
system is used by the astronomer Naburiannuto to
record and predict the positions of the Sun, the Moon and the
planets. Hanno the Carthaginian travels down
the western coast of Africa. Hecataeos (549
- 486) mentions India in his writings, proving that the exchange
between Far East and Greece was already significant. Development
of technology and agriculture in China. Confucius (Kong
Fu Zi) (551-479) teaches general rules of behaviour
that are still followed in China in many places. As Socrates or Jesus
Christ he does not directly write, and his sayings are
recorded by followers. Emphasis is not placed on knowledge itself
as a goal, but, in contrast, on knowledge of moral rules (in
particular family values).
494 BC Destruction of Miletus by the Persians.
~490 BC Parmenides (Elea
~515 - ?) in contrast to Heraclitus places
emphasis on Permanence.
461-456 BC The wall from Athens to the Piraeus
~450 BC Empedocles (Agrigente,
492-432) choses the four elements (Earth, Water, Air and Fire)
and their combination as making all things. His view of the creation
of living forms is strikingly similar to the views much later
held by selective theories derived from Darwin's
thought. He also emphasizes the combinatorial nature of living
forms. Before this time, the Greeks disputed which one(s) of
four possibilities were the originalelements: some
said one, some said another, some said two together. Empedocles
said he thought there were four original elements: Earth, Air,
Fire, and Water. He thought that everything else come about through
their combination and/or separation by the two opposite principles
of Attraction and Repulsion. Leucippus (Abdere
~490 - ?) proposes that things are made of Atoms, unbreakable
structures which can combine together in an infinite way "No
Thing comes to being by itself, but everything is derives from
a Law (Λογος) and is under
the constraint of Necessity" Diogenes of Apollonia (Apollonia,
Phrygia or Crete? 499/98 - 428/27) writes his Περι φυσεως in
an eclectic fashion, agreeing in some points with Anaxagoras and
in others with Leucippus. Like Anaximenes,
he says that the primary substance of the universe is Air infinite
and eternal, from which by condensation, rarefaction, and change
of state, the form of everything else arises. Like Anaximander, Diogenes regards
the sea as the remainder of the original moist state, which has
been partially evaporated by the sun, so as to separate out the
remaining earth. The earth itself is round, that is to say, it
is a disc. Its solidification by the cold is due to the fact
that cold is a form of condensation. The chief interest of Diogenes is
a physiological one, of the same character as that of the pseudo-Hippocratean
literature, and there is much to be said for the view that the
writers of these curious tracts made use of him very much as
they did of Anaxagoras and Heraclitus.
Living creatures arise from the earth, doubtless under the influence
of heat. Their souls are air, and their differences are due to
the various degrees in which it is rarefied or condensed. No
special seat, such as the heart or the brain, is assigned to
the soul; it is simply the warm air circulating with the blood
in the veins. The views of Diogenes as to his
theory of sensation amounts to this, that all sensation is due
to the action of air upon the brain and other organs, while pleasure
is aeration of the blood. But the details of the theory can only
be studied properly in connection with the Hippocratean writings;
for Diogenes does not really represent the old
cosmological tradition, but a fresh development of reactionary
philosophical views combined with an entirely new enthusiasm
for detailed investigation and accumulation of facts, in a way
a data-driven complete archaism with respect to the creation
of hypothesis-driven Science that other philosophers developed.
~420 BC Democritus (Abdere
460 - 370 BC) further develops the atomic theory. His main stance
is that atoms whirl in the void, where they can combine together
in all varieties of forms. This reconciles both the Parmenides view
of unchanging matter, and the Heraclitus view
of ever changing matter.
441 BC Melissos (Samos,
500 - 440), commanding the float at Samos defeats Pericles. He
states that the laws of nature are the same everywhere in the
~400 BC Hippocrates (Cos 460 - 377) founds
the profession of medicine in Greece, with scholars studying
under the protection of Asklepios, the god of Health.Among many
observations, mostly inaccurate, Hippocrates determines
that the male contribution to a child's heredity is carried in
the semen. He founds the Asclepiades, a school of medicine that
was to subside for several centuries. One of the things for which
he is remembered is his theory that the human body is composed
of the four elements (earth, air, fire, water) plus four fluids
or humors: αιμα or blood, produced by the
heart; χολη or yellow bile, produced by
the liver; μελανχολη or
black bile, produced by the spleen; and φλεγμα or
phlegm, produced by the brain. Hippocrates is said to have established
the oath that all men professing medicine must obey:
I swear by Phoebos the Physician and Asklepios and Health
and all Heal, and all the gods and goddesses, that, according
to my ability and judgement, I will keep this oath and this
stipulation. I reckon him who taught me this art equally dear
to me as my parents, to share my substance with him, and relieve
his necessities if required, to look upon his offspring in
the same footing as my own brothers, and to teach them this
art, if they shall wish to learn it, without fee or stipulation
and that by precept, lecture and every other mode of instruction,
I will import a knowledge of the art to my own sons, and those
of my teachers and to disciples bound by a stipulation and
oath according to the law of medicine, but to none others.
I will follow that system of regimen which, according to my
ability and judgement, I consider for the benefit of my patients
and abstain from whatever is deleterious and mischievous. I
will give no deadly medicine to anyone if asked, nor suggest
any such counsel, and in like-manner I will not give to a woman
a pessary to produce abortion. With purity and with holiness
I will pass my life and practice my art. I will not cut persons
laboring under the stone, but will leave this to be done by
men who are practitioners of the work. Into whatever houses
I enter, I will go into them for the benefit of the sick, and
will abstain from every voluntary act of mischief and corruption
and further, from the seduction of females or males, of freemen
or slaves. Whatever, in connection with my professional practice,
or not in connection with it, I see or hear, in the life of
men, which ought not to be spoken of abroad, I will not divulge
as reckoning that all such should be kept secret. While I continue
to keep this oath, unviolated, may it be granted to me to enjoy
life and the practice of the art, respected by men, in all
times, but should I trepass and violate this oath, may the
reverse be my lot.
The Greeks use a water clock, which measures the outflow of
water from a vessel, to measure time.
~390 BC Platonos (Plato) (427 - 347) summarizes
the theories developed, but never written, by Socrates.
He states that the world as we understand it is a projection
of Reality, to which we have thus indirectly access. This leads
him to look for Universals (archetypes) to describe Reality,
including biological forms and species. This is often in line
with the development of pythagorean science and places the study
of mathematics at the root of philosophy. Among the many things
for which he is remembered is his idea that there are two worlds.
The world that we see is just a reflection, an imperfect image
of the real world. It is transitory, and will decay. The real
world which we cannot see directly, is good, perfect, eternal,
and static or unchanging. In this way Plato conciliates Parmenides and Heraclitus,
in a way that differs from the way the Atomists chose. In the
real world, there is obviously no variation or change, nor need
for any, because all the organisms there, the Archetypes, are
perfect. The variation we see among organisms here is because
they are imperfect copies of the real Archetypes in the real
~350 BC Aristotle (Stagiros,
384 - Chalcis, 322), one of Platos most
famous pupils, creates the first major rules of logics, which
we know today as first order logics. This is at the root of all
hypothetico-deductive methodology. Logics derives from geometry.
The principle of the excluded party (this or that, and not both
together) means simply that one cannot have two solids at the
same time at the same place. Aristotle defines
ten categories needed to represent knowledge: ουσια, ποσοτης, ποιοτης, προς τι, κεισθαι, εξις, τοπος,
χρονος, πραττειν, παθειν (in
latin essentia, quantitas, qualitas, ad
aliquid, situs, habitus, locus, tempus, agere, pati).
The corresponding classes are kept till their redefinition by Immanuel
Kant during the eighteenth century. Aristotle groups
500 known species of animals into eight classes. In terms of
the organization of the universe, Aristotle asserts
that the Earth is both the center of the universe and, following Empedocles,
one of the four primordial elements. Earth is round. It is the
first sphere followed by spheres of water, air, and fire in that
order, in their proper places (this follows Anaximandre,
with spheres instead of cylinders). This order follows the reasoning
of Anaximenes based on the fact that a thrown
clod of earth always falls, as does rain, while flames of fire
constantly ascend to their sphere. The harmonious relationships
and interworkings of these spheres is inspired from Plato,
it can be perceived as a celestial music: the music of the spheres.
Above fire is the Moon, and this sphere delimits matter of a
different kind. Beyond the Moon are spheres for the Sun, the
planets, and the stars, which are carried around the Earth in
daily, complicated inclined orbits. All matter inside of the
Moons orbit is different in kind from matter above the
Moon. Reminiscent of Platos ideas, Aristotle theory
states that terrestrial matter decays and is ephemeral, while
celestial matter, the aether, is unchanging and eternal. This
idea was subsequently borrowed and incorporated into much Christian
beliefs as the location for Heaven, and thus was important later
in the rejection of Copernicus and Kepler as
heretics because they said the Earth was just another planet
revolving around the Sun. The implication of a Sun-centered system
was definitely not a reassuring thought to Medieval Christians
who thought of heaven as the place in the aether where would
go all the Plague victims who were Christians when they died.
As evidence for his view of a round Earth, Aristotle cites
examples of things like how ships disappear over the horizon,
mast last, as though sailing around a curve. Heraclides
of Pontus (388 - 315), another pupil of Plato is one
of the first people to say that the apparent daily rotation of
the heavenly bodies is not due to their motion, but rather, due
to the rotation of the Earth around its own axis. He also states
that Venus and Mercury revolve around the Sun, not the Earth.
These ideas were not well-accepted by people who thought of down
as down, not to the center,
yet these two discoveries constituted important steps toward
the Copernican theory.
Rain is measured in India on a regular basis. Iron used as a
basic working material in China. Chinese astronomers describe
115 stars and 28 constellations with their coordinates.
332 BC Alexander the Great is
crowned Pharaoh of Egypt in Memphis. It may be that the enthronement
as Pharaoh included divine honours to Alexander.
It is a fact that Persian rule in Egypt, in a strange contradiction
to the Persian treatment of most other conquered nations, had
been oppressive and had included the desacration of Egyptian
holy shrines. The popular image of Alexander being welcomed as
the liberator of Egypt, although Arrian limits this 'friendliness'
to the Persian governor Mazaces, might be rather realistic. The
whole country of Egypt falls into Alexander's hands without a
331 BC Alexander is back
from a 1100 km detour in Lybia, where he consulted the oracle
in Siwa. He is said to establish Alexandria on the Egyptian coast,
the future metropolis of the Hellenistic world (although both
Arrian and Plutarch record the foundation of Alexandria before
the Siwa episode.) All our sources state that, after becoming
master of Egypt, Alexander felt a strong urge (or 'pothos' if
you like) to visit the oracle at Siwa. The Siwa oasis was then
called Ammonium or Hammon, its inhabitants Hammonii. It was considered
to be one of the three great oracles in the ancient world, together
with Delphi and Dodona in Greece. The priests of these oracles
stayed in contact with each other. Especially during the oppressive
Persian reign, for the Siwah priests this contact might have
been quite valuable. Within the polytheistic view, there were
little problems identifying the Egyptian Ammon, the Greek Zeus
or the Roman Jupiter as one and the same deity. Halas
ammoniakôn (ἁλας άμμονιακων ammonium chloride),
which much later played such an important role in bridging mineral
chemistry with organic chemistry, is discovered at the temple
of Zeus Ammon in Lybia.
~330 BC Theophrastos (Eresos, 372-287) describes
more than 550 plants in a treaty that was to be copied for many
generations until printing was invented in Europe. The Greek
explorer Pytheas of Phoceus (Marseilles) reaches
~325 BC Alexander the Great orders
his admiral, Nearchus, to explore the Indian Ocean, Persian Gulf,
and Euphrates. Alexanders conquests bring much of the known
world under Graecian domination, including introduction of Greek
language, thoughts, and philosophies in areas where these were
previously not known.
~320 BC Aristotle states that the male provides
the form and the female the raw material for the construction
of their offspring. His refinement of the systems of animal and
plant classification has profoundly influenced the course of
biological thought ever since. His classification system includes
what was later called in Latin the Scala naturae. He states
that all organisms are arranged in a hierarchy from simplest
to most complex, like rungs on a ladder with no vacancies, no
mobility, and no change possible since all the spots are full.
This idea also was to be borrowed by early Christianity where
it replaced the archaic Hebrew concept of Let the Earth
bring forth. . . Our current technical terms genus and species are
Latin translations of the Greek words first used by Aristotle.
Aristotle thought that pangenes, particles representative of
the various organs, pass from those organs to the reproductive
elements (whatever they may be) and convey their own nature/characteristics
to the a preformed, tiny human that just grows in the mother.
This belief was held by people up through and including Darwin
(in particular by Charles Bonnet), and has led
to some very interesting folkloric explanations for birthmarks
and birth defects justly ridiculed by Maupertuis.
Aristotle speculates whether an embryo just grew/enlarged from
the preformed child or undergoes development from some undifferentiated
(no distinct body parts) unit to a differentiated embryo. This
speculation led to 2000 years of debate and controversy. Praxagoras
of Cos discovers the difference between the arteries
and the veins.
~300 BC Diocles of Karystos (? - 293) writes
a book that advances the knowledge of anatomy. He tries to fathom
the causal connection between symptom and disease, in which endeavours
he is imitated by Praxagoras of Cos, who establishes
the diagnostic importance of the pulse. Epicurus (341-270)
expands the theory of the Atomists. Some of his work is summarized
in Diogenes Laertius Book
X. In fact Epicurus does not improve on the works
of Leucippus and Democritus,
but, rather, regresses. Rather than propose that the movements
of atoms is symmetrical in its principle (i.e. has no preferred
direction) he proposes that there is a preferred direction from "up" to "down",
like in rainfall. This forces him to add a principle of some
kind of shock (πνηγη) to make them collide and interact.
~290 BC Euclid
of Alexandria (325 - 265) writes his "Optica" which
is the first Greek work on perspective. Euclid also
writes the following books which have survived: "Data" (with
94 propositions), which looks at what properties of figures
can be deduced when other properties are given; "On
Divisions" which looks at constructions to divide a
figure into two parts with areas of given ratio; "Phaenomena" which
is an elementary introduction to mathematical astronomy and
gives results on the times stars in certain positions will
rise and set. Euclid's following books have
all been lost: "Surface Loci" (two books), "Porisms" (a
three book work with, according to Pappus, 171 theorems and
38 lemmas), "Conics" (four books), "Book of
Fallacies" and "Elements of Music".
~265 BC First contact of the Romans with Greek
medicine through prisoners of war.
263 BC Travelers from Sicily bring the sundial
to Rome, where it is displayed on the Forum.
~260 BC Archimedes
of Syracuse (287-212) applies the method of
exhaustion, which is the early form of integration, to obtain
a whole rangeof important mathematical results. He also gives
an accurate approximation to p, showing
that the exact value lies between the values 310/71 and 31/7.
This he obtains by circumscribing and inscribing a circle
with regular polygons having 96 sides. He shows that he can
approximate square roots accurately. He invented a system
for expressing large numbers. In mechanics Archimedes discovers
fundamental theorems concerning the centre of gravity of
plane figures and solids. "On floating bodies" is
a work in which Archimedes lays down the
basic principles of hydrostatics. His most famous theorem
which gives the weight of a body immersed in a liquid, called Archimedes'
principle, is contained in this work. He also studies the
stability of various floating bodies of different shapes
and different specific gravities.
~240 BC Eratosthenes
of Cyrene (of Greek or Chaldean descent) (~276-194)
suggests that the Earth moves around the sun and maps out
the course of the Nile. He notes that during the spring or
autumn equinox, the noon Sun is directly overhead for residents
of the (south) upper Nile area, but not at Alexandria, in
Northern Egypt. There, the Sun was 7° off from straight
up. Since this is about 1/50 of 360°, he calculates that
the distance from Alexandria to the upper Nile, which was
known, is also 1/50 of the circumference of the Earth. His
calculations came very close to modern calculations: the
diameter which he calculated in this way is only100 km off
from the currently accepted value of the diameter of the
Earth. Thus, not only is Earth round, but we can measure
its circumference. This was not accepted for many centuries.
For several decades, Eratosthenes serves as the director
of the famous library in Alexandria.
~220 BC Apollonius of Perga (Perga, 265 -
Alexandria, 170) postulates that the planets revolve around the
Sun and the Sun revolves around the Earth. Apollonius is
believed to be the inventor of the system of epicycles and eccentric
circles, used extensively by Hipparchos of Nicaea. He also wrote
a monumental treatise on conic sections "On Conics".
In this treatise, the term ellipse is first used.
206 BC - 220 AD During the Han period, mathematics,
coming from an unknown origin possibly from India, develops briefly
in China. This science is soon almost forgotten, to be replaced
by the study of proper behaviour of the citizen in the Empire
rather than the cultivation and construction of knowledge (development
of Confucean ethics instead of Science and Philosophy).
~200 BC Marcus Porcius Cato (234-149)
publishes a treaty on agricultural techniques De agricultura.
The use of gears leads to invention of ox-driven water wheel
~ 160 BC The first Westerner to document the
therapeutic use of leeches is
Νίκανδρος ὁ Κολοφώνιος Nicander
of Colophon (Clarus,
near Colophon 200-130) in his medical poem, Αλεξιφάρμακα Alexifarmaka. Nicander describes
poisons in general, analyses 19 specific poisons (8 animal and
11 from plants), and lists appropriate cures. He subsequently
writes many books, in particular about medicine and animals.
159 BC The first water clock (clepsydra) is
displayed in Rome.
~140 BC Hipparchos of Nicaea (190 -125) ,
makes important astronomical discoveries and invents trigonometry.
He creates the first catalog of the stars, showing their brightness
and position. He also discovers the precession of the equinoxes
by comparing star observations of different years and noticing
that the stars had shifted eastward. He explains these facts
by a slow forward motion of the equinoxes. Crates of
Mallus forms his great globe of the world.
124 BC The recruitment of administrative personnel
in China is performed by a nation-wide competition. The applicants
are supposed to have an exhaustive knowledge of the classical
texts (meaning texts dealing with behaviour and social rules,
including formalisation of Art, but no Science whatsoever). This
interesting "democratic" system lasted for two millenia
and fixed China to a rigid pattern of behaviour for all this
period of time, preventing access to Science because of the content
of the examinations.
~100 BC The Romans speculate that mares can
be fertilized by the wind.
~70 BC Lucretius (99 BC - 55 BC) in his De
Rerum Natura develops the atomic theory and uses
it to explain Reality. He propagates the error of Epicurus
under the term clinamen.
63 BC Pompeiuss battles and conquests
lead to Roman rule of most of the western world.
January 1, 45 BC On the advice of an Alexandrian
astronomer, Julius Caesar decides to correct the problem of the
non integer number of days in the year by adding a day to the
calendar every fourth year. It had always been difficult for
humans to devise a calendar that works precisely because the
solar year is not exactly 365 days long and the lunar month is
not exactly 29 days. This makes up for the 365.25 days of the
~0 AD-1452 begins
the Christian era, with the spreading of a sect derived from
a proselytic Israelit sect (Essenians) based on the sayings of
prophet Isaiah, among free men but also among slaves. This religion
had to have a decisive impact in the development of Science by
its role in transmitting and interpreting Greek knowledge into
its own categories. Perhaps the most important contribution of
this religion to science is its emphasis about the universality
of knowledge, and the need to spread it throughout the world
(still active today).