2. Proto-scientists.
What was known in the ancient world.
Ancient astronomy, time and the seasons, eclipses
and the Antikythera device. Euclid, Archimedes, Hero.
It is fairly clear that science as we understand it today evolved from
the two quite different strands of craftsmanship and philosophy. As
men took up farming and became more settlers than hunters the seasons
must have become of paramount importance, and nowhere was that more
important than in the Nile deleta where the forecasting of the
seasonal inumndation of the delta, which replenished the soil with
silt washed downriver, was a priestly duty.
It is difficult for us, with our modern communication systems, to
understand the difficulty of working out the cyclical nature of the
seasons, and of the marking of the passage of time in months, let alone
hours and minutes. But more primitive men and women had at least one
advantage over us; they could see the stars. In our well lit suburbs it
is difficult to see the stars at all and some people now go to their
graves without having seen the milky way - the mass of faint stars that
we now know to be the edgewise view of our own home galaxy.
So the first astronomers were probably agriculturalists, maybe
shepherds looking for spring, when the lambs would be born, or farmers
who wondered when would be the most appropriate time to plant the seed
saved from last year to provide food for the next. The most obvious
ways of telling the time were by the sun, and telling the time by the
sun was common up until the middle ages in England. The sun, at
least in the northern hemisphere, is lower in the sky at noon in
winter and highest in the sky at midsummer. Once this has been
spotted it is easy to keep track of the passage of days by using
sticks or stones and their shadows to get a very good idea of the
passage of days.
The moon's motion also serves as a clock and beats out the months, as
the word month suggests. Months are not of uneven lengths as our civil
month suggests, the interval between new moons is quite precise. It is
because the number of months does not fit exactly into the year as
measured by the sun that we have devised our calendar of months of
different lengths.
Someone isolated on a desert island with no clocks and no calendar, or
locked in a prison cell will resort to tracking time by scratching
marks on a rock or wall, and such primitive calendars are found. One
such example found recently was at the Grotte du Tai, a cave in the
south-west of France. This bone calendar record has been dated to
the end of the last ice age, roughly 12,000 years ago. The calendar
is about three inches by one inch and has marks which correspond to
the the days, the soltices and the years.
This primitive calendar ante-dates such well known monuments as
Stonehenge by 7,000 years. We don't know what this calendar was used
for, but it is hardly linkely that the record was kept for three years
without some prpose in mind, which is as likely to have been practical
as religous. But, of course the practical and the religous motives of
people are often fused together, and asd recently as four hundred years
ago the phases of the moon were believed to influence the potency of
herbs gathered to cure the multifarious ills of mankind.
We are all now familiar with the idea that the earth is a globe, and
most of us are willing to believe that the earth rotates about the
sun, but these two concepts are by no means obvious, and indeed, they
violate ordinary common-sense. Together with the knowledge that the
moon rotates in its turn about the earth we are able to forecast the
eclipses of the sun and the moon, which again are today phenomena not
often noticed.
Total solar eclipses are very dramatic, but they don't often happen in
England and most people will live out their lives without seeing one.
In the countries around the mediterranean they are more frequent, and
given the importance of the sun in an age without street lighting or
heated greenhouses it is scarecely surpring that explanations for the
solar eclipses should have been sought and attempts made to forecast
them.
Thales 624 BC to 546 BC
-----------------------
Thales was born and died in Miletus and his most enduring work was the
prediction of a solar eclipse in 585 BC, which is supposed to have caused
the warring armies of the Medes and the Lydians to sign a peace treaty.
The story is related by Herodotus 150 years later, but Thales only
forecast the Year in which the eclipse was to take place, not the actual
date, May 28th our style. The aborted battle is said to be the first
historical event which can be dated to the exact day, since the theory of
Newton allows us to calculate the motion of the moon and the Sun and work
out when the shadow band of the eclipse of that year passed through Asia
Minor.
It is believed that Thales visited Babylon and that his knowledge was
derived from the Babylonians. he studied magnetism and deduced the height
of a pyramid in Egypt by measuring its shadow and that of a stick of known
length. Aristotle tells us that Thales was also a successful
entrepreneur who cornered the market in olive presses before a
particularly good year for olives, and thereby made a fortune. Plato
says that he once fell down a well while walking at night with his head up
studying the constellations. Whatever the truth of the stories about
Thales he was certainly well remebered long after his death by his fellow
Greeks and it is right that we should remember him too, for his curiosity
and interests were wide-ranging.
He believed that the fundamental stuff of the universe was water.
Anaximander 610 BC to 546 BC
-----------
A pupil of Thales he introduced the sundial to greece from egypt and
babylonia. He also attempted to draw a map of the known world and
recognized that the heavens appeared to revolve around the pole star.
He taught that the earth as a cylinder curved in the north-south
direction, which accounted for the changing aspect of the stars as
latitude changed.
No copies of his works have been found, we only know of him through
the comments of others.
Pythagoras 582 BC - 497 BC
----------
Anaximenes
----------
Eupalinus fl 600 BC
---------
Democritus 470 BC to 380 BC
----------
Socrates 470 BC to 399 BC
-------
Meton 440 BC to ??
-----
Plato 428 BC to 348 BC
-----
Plato was a Athenian of good family, whose original name was
Aristocles, but he was nicknamed Plato, "broad" for his broad
shoulders, at school and it stuck. Plato was much more like a modern
philosopher than a scientist. He became a disciple of Socrates in 409
BC and after the execution of Socrates in 399 BC he left Athens and
travelled widely in Africa and Italy returning to Athens in 387 BC.
During his travels he is supposed to have been captured and held to
ransom by pirates! His foundation, the Academy, named after the owner
of the site, gave us our word for almost any seat of higher learning.
Plato believed that heavenly bodies moved in circles because circles
were perfect forms, the universe must be spherical, for the sphere was
the most perfect of forms. All this is very mystical and tinged with
the numerology of the Pythagoreans.
In his work, the Timaeus, he develops the idea of an analogy between
the universe and man, the macrocosm and the microcosm, an idea which
persisted into the Middle Ages. He condemned experiment as impious or a
base mechanical art, but praised mathematics. His theory led him to
postulate that "forms" or ideas alone possess reality, which he denied
to individuals. In one of Plato's dialogues he mentions a fictitious
land, Atlantis, which has been a fertile land for fantasy ever since!
His theory that philosophy was a preparation for kingship was put to
the test when he was employed briefly as tutor to the King of Syracuse
(Sicily). The King behaved badly and Plato had difficulty getting back
to Athens.
Plato's school in Athens survived him for nine centuries being finally
closed by the Emperor Justinian in 529 AD!
Aristotle 384 BC - 322 BC
-------------------------
Aristotle was born in 384 BC at Stagira in northern Greece and died in
322 BC on the island of Euboea, in the Aegean. He was the son of the
physician to Philip, King of Macedon, but was brought up by a friend
of the family. He is said to have had a lisp and when young to
have been something of a dandy; but from the age of 17 until Plato's
death he studied philosophy under him in Athens. It is not clear why
he moved from Athens after this, he may have been disappointed at not
being designated Plato's successor, or it may have been for political
reasons, since Macedon was at war with Athens at the time. He himself
gave as his reason the increasing emphasis on mathematics and theory in
the Platonic School, and it is certainly true that Aristotle was a much
more practical man than Plato. He was for a time the tutor of Alexander
the Great.
He founded his own school, the Peripatetics, so called from their habit
of carrying out their discussions whilst walking in the gardens of the
Lyceum in Athens.
Archimedes
----------
Euclid
------
Aristarchus
-----------
Eratosthenes
------------
Hipparchus
----------
Lucretius
---------
Hero b. 20 A.D.?
---
Very little is known about the personal life of Hero - and until
recently it was not clear which century he lived. Unlike most of his
fellow greeks he was an experimenter, an engineer, and he is credited
with using the power of steam for the fist time, although there were no
applications of his discovery other than toys or temple tricks. But, of
course, there was no tradition of the use of other than muscle power to
do useful work.
Ptolemy b. 75 A.D.
-------
Very little is known of the life of Claudius Ptolemy, who was greek, or
perhaps Egyptian. The work for which he became famous was mostly not
original, and his system of astronomy drew principally on the works of
Hipparchus, whose own works are lost. The earth was seen as the centre
of the universe with the moon, Mercury Venus the Sun Mars Jupiter and
Saturn orbiting it. The orbits were circles with superimposed epicycles,
to save the appearances. The use of the system in forecasting positions
was good enough for naked-eye observations, and not until Tycho brahe
in the 16th century were the inaccuracies such as to require refinement
to the theory. His star-catalogue copied from Hipparchus used the same
constellations that we use today, and his work was described by the
Arabs who translated and preserved his work Al-Magest, "The Greatest".
He also wrote on optics and trigonometry and his geographical work,
which used a figure for the radius of the earth which was seriously
smaller tha the true value, was later to mislead Columbus into
attempting to reach the Indies by travelling west.
Galen 130 - 200 A.D.
-----
Galen was born in Pergamum (now Bergama) in Turkey, the son of an
Architect. He travelled extensively in the Eastern Metditerranean in
his youth and visited the medical school at Alexandria. In 159 he was
appointed physician to the gladiatorial school at Pergamum, but by 164
he had settled in Rome where he was for atime court physician to the
Emperor Marcus Aurelius. Galen became famous for his work in anatomy,
but the disection of corpses was in disrepute and his disections were
of animals, dogs, pigs, goats and monkeys. He was an early
vivisectionist, showing the importance of the spinal cord by cutting it
in animals at various points and describing the paralysis so caused.
Galen's system of physiology missed the circulation of the blood.
Although he realised that the blodd must get from the left to the
rightn side of the heart, he believed that there must be very small
holes to allow passage. He was the first to use the pulse as a
diagnostic aid and correctly described the flow of urine through the
ureters to the bladder. He wrote much and thought little of the work of
Hippocrates. Although not a Christian, he was a monotheist, and in his
work he ascribed the nature of all things to the purposes of God. This
made him the most poular of the ancient medical writers to the
Christians, and his authority was absolute up to the time of Vesalius
in the middle ages.
The seven philosophical strands.
-------------------------------
1. Pythagoreanism.
-----------------
2. Eleaticism.
--------------
3. Atomism
----------
4. Platonism.
-------------
5. Aristotleanism
-----------------
6. Stoicicism.
--------------
7. Neo-Platonism.
----------------
References.
-----------
Farrington
Greek Science
Penguin
Last updated 23rd December 1998
Home page!