The document summarizes key Pre-Socratic philosophers and some of their important contributions. It discusses Thales of Miletus discovering static electricity in 500 BC by rubbing fur on amber. It also mentions Pythagoras discovering the Pythagorean theorem for which he sacrificed an ox, and Parmenides arguing against nothingness which influenced Democritus to propose atoms. Zeno introduced paradoxes that have challenged philosophers for over two millennia, while Democritus discovered atoms in 400 BC by breaking a seashell into powder.

1. Alejandro, Joanna Raveana
2-1BSIT

2. A number of early
Greek philosophers active before
and during the time of Socrates are
collectively known as the Pre-
Socratics. Their inquiries spanned
the workings of the natural world as
well as human society, ethics, and
religion, seeking explanations based
on natural principles rather than the
actions of supernatural gods. They
introduced to the West the notion of
the world as a kosmos, an ordered
arrangement that could be
understood via rational inquiry.
PRE-SOCRATIC ERA

3. THALES OF
MILETUS
PYTHAGORAS
HERACLITUS
PARMENIDES
ANAXAGORAS
• He was well-known in
antiquity and was
influential on later
philosophers.
•He is famous for the
saying ‘You cannot step
in the same river twice.’
• Another of his sayings
was ‘Everything flows.’
•He is a teacher and
appears to have authored
only one work
•A poem On Nature, this
poem tells of the journey
of him when he search for
wisdom.
•He believed that the
whole universe, all that
exist, is timeless and
unified.
PRE-SOCRATIC ERA
635 BC 575 BC 530 BC 515 BC 500 BC
• First systematic
philosopher of the
Western world.
• First to reject
supernatural explanations
and seek reasons behind
events.
• Devising several
geometric theories
• Static electricity which
Thales’ studied
•Best known of all the
philosophers in pre-socratic era
•Pythagoras took this special case
and worked out a theory which
worked on all right angled
triangles.
•As well as this he worked out
the relationships between musical
notes, figured out all regular
solids, and was the first to study
irrational numbers.
•he also did much work on
mystical beliefs such as
reincarnation
•Treated all events as
scientifically explicable
instead of being caused
by supernatural agents.
•Famously he declared
that the sun was an
enormous, hot rock in
the sky and not the
chariot of Apollo.

4. EMPEDOCLES
GORGIAS
ZENO
PROTAGORAS
DEMOCRITUS
•Universe composed of
Earth, Water, Air, & Fire
•He believe for existing
things to go into
nothing.
•He firm belief in
reincarnation and he
died because he prove it.
• If Plato is to be believed,
Gorgias believed in nothing.
•He was the first known
Nihilist.
•He tried to prove that nothing
exists at all.
•Gorgias used the following line
of argument: Nothing exists, or
if it does exist we cannot know
it, or if we can know it it is
impossible to communicate it.
• Student of Parmenides.
He has staunch support
for the theories of his
teacher.
•He is best known for
his paradoxes, the most
famous are the
arguments against
motion described by
Aristotle in his Physics
•Protagoras famously said
“Man is the measure of all
things.”
•All that exists can be judged
against man’s sensation and
interpretation of it.
•Some philosophers have seen
the whole of Plato’s work as a
way of finding a third path
between Parmenides’ unity
and Protagoras’ relativism.
PRE-SOCRATIC ERA
485 BC 485 BC 485 BC 485 BC 455 BC
•Most successful of the ancient
philosophers from a scientific
standpoint.
•He believed that the whole
universe was governed by
natural laws
•Predicted the existence of
atoms and vacuums.
•His wide ranging studies also
took on the finer points of
philosophy, biology, human
society, and geometry.

5. Thales of Miletus discovered
static electricity in 500 BC.
He discovered that static
could be made by rubbing
fur on substances, such as
amber. The Greeks noted
that the charged amber
buttons could attract light
objects such as hair.

6. Pythagoras has commonly been given
credit for discovering the Pythagorean
theorem, a theorem in geometry that
states that "in a right-angled triangle the
square of the hypotenuse is equal [to the
sum of] the squares of the two other
sides"—that is, According to a
popular legend, after he discovered this
theorem, Pythagoras sacrificed an ox, or
possibly even a whole hecatomb, to the
gods.

7. Parmenides made
the ontological argument
against nothingness, essentially
denying the possible existence
of a void. According
to Aristotle, this
led Democritus and Leucippus,
and many other physicists, to
propose the atomic theory,
which supposes that everything
in the universe is either atoms or
voids, specifically to contradict
Parmenides' argument.

8. It is clear, however, that the work
developed a skeptical argument,
which has been extracted from the
sources and translated as below:
•Nothing exists;
•Even if something exists, nothing can
be known about it; and
•Even if something can be known
about it, knowledge about it can't be
communicated to others.
•Even if it can be communicated, it
cannot be understood.

9. Zeno's paradoxes have puzzled,
challenged, influenced, inspired,
infuriated, and amused
philosophers, mathematicians,
and physicists for over two
millennia. The most famous are
the arguments against motion
described by Aristotle in
his Physics, Book VI

10. Democritus discovered
atoms in 400 BC and made
the first atom model. He
took a simple seashell and
broke it in half. He then took
that half and broke it in half
over and over and over
again until he was finally left
with a powder. He took the
smallest piece and tried to
break that but could not.