Thales’ ProblemThales’ ProblemNatural Philosophers in Natural Philosophers in

Ancient GreeceAncient Greece

Greek Thought: a Neo WayGreek Thought: a Neo Way

• Did not have to resort to animistic or Did not have to resort to animistic or deistic explanationsdeistic explanations

• Assumed that the cosmos was Assumed that the cosmos was understandable, ordered and constructed understandable, ordered and constructed intelligiblyintelligibly

• That as humans we have the special That as humans we have the special capacity: capacity: we could figure it all outwe could figure it all out…the …the question drove them like a splinter in the question drove them like a splinter in the mind…mind…

Hubris and NemesisHubris and Nemesis

• Be careful!!Be careful!!

• Explosions in Human Knowledge…Explosions in Human Knowledge…

Q: What is the whole world Q: What is the whole world made up of?made up of?

ThalesThales – Thales (625-550bc) was a smart guy, Thales (625-550bc) was a smart guy,

revered by Greeks and Romans in ancient revered by Greeks and Romans in ancient worldworld

– Lived in Lived in MiletusMiletus, an Athenian colony and , an Athenian colony and hotbed of intellectuals on eastern shore hotbed of intellectuals on eastern shore of Aegean (Turkey today)of Aegean (Turkey today)

• Thales’ Answer: Thales’ Answer: waterwater

The Guys from Miletus The Guys from Miletus Debate: Debate: Anaximander’s Anaximander’s AnswerAnswer

• Everything is from and made out of Everything is from and made out of

the Boundlessthe Boundless

The Guys from Miletus The Guys from Miletus Debate: Debate: Anaximenes’ Anaximenes’ AnswerAnswer

• Everything is from and made out of Everything is from and made out of

… ….Vapor….Vapor…

Parmenides’ Answer:Parmenides’ Answer: 540-480bc540-480bc

1.1. Everything has always existedEverything has always existed

2.2. Nothing can come from nothingNothing can come from nothing

3.3. Nothing really changesNothing really changes

4.4. Senses are unreliableSenses are unreliable

• But his problem is how are the But his problem is how are the changes in the constant universe changes in the constant universe generated?generated?

Heraclitus’ Answer Heraclitus’ Answer 540-480bc540-480bc

1.1.Everything is in fluxEverything is in flux2.2.Opposites dominateOpposites dominate3.3.World based on interactions – thus World based on interactions – thus

changechange4.4.Senses are reliableSenses are reliable

• His problem: what holds everything His problem: what holds everything together? together?

Who’s right?Who’s right?• Parmenides Parmenides 540-480bce540-480bce

– Everything has always Everything has always existedexisted

– Nothing can come from Nothing can come from nothingnothing

– Nothing really changesNothing really changes– Our senses are Our senses are

unreliable when they tell unreliable when they tell us of the transitoriness us of the transitoriness of worldof world

– RationalismRationalism

• Heraclitus Heraclitus 540-480bc540-480bc

– Everything is in Everything is in fluxflux

– Opposites Opposites dominatedominate

– World based on World based on interactions – interactions – thus changethus change

– Senses are Senses are reliablereliable

– EmpiricismEmpiricism

Empedocles’ Empedocles’ Answer…Answer…

• From From Parmenides, he took…Parmenides, he took… – There is an unchanging substratumThere is an unchanging substratum– 4 unchanging roots: fire, water, earth and air4 unchanging roots: fire, water, earth and air

• From From Heraclitus , he took…Heraclitus , he took…– But world is changing; you can trust your sensesBut world is changing; you can trust your senses– Yet 2 forces interplay and yield changesYet 2 forces interplay and yield changes

•““love” - attractionlove” - attraction•““strife” – separation/repulsionstrife” – separation/repulsion

He combined the two philosophers’ ideas

Empedocles: 2 ForcesEmpedocles: 2 Forces• Filotis: Filotis:

– love – gravitylove – gravity

• Neikos =Neikos =– escape or strife – escape or strife –

centifugalcentifugal

• He believed planets He believed planets orbiting sun were orbiting sun were result of 2 forces…result of 2 forces…

http://www.petra.gr/Theology/empedocles.htm

Pythagorus’ Answer : Pythagorus’ Answer : NumbersNumbers570-495 BC of Samos570-495 BC of Samos

• ““Numbers are things, things are Numbers are things, things are numbers”numbers”

• ““Music of the spheres”Music of the spheres”– Ratios of numbers explain harmoniesRatios of numbers explain harmonies– In awe of the mysticalIn awe of the mystical

– Irrational numbersIrrational numbers• If numbers are things, where are they?If numbers are things, where are they?•tried to explain themtried to explain them

– Pythagoreanism became a religionPythagoreanism became a religion

3.14.. ∞… ∂…99.999 ∏…

Democritus’ Answer: AtomsDemocritus’ Answer: Atoms

• Eternal and immutable pieces of materialEternal and immutable pieces of material

• Invisibly small and indivisibleInvisibly small and indivisible

• All of it is of the same stuffAll of it is of the same stuff

• Comes in different sizes shapesComes in different sizes shapes

• Cling to each otherCling to each other

• In perpetual motionIn perpetual motion

• Soul is also made of these atomsSoul is also made of these atoms

Sophists v Socrates Sophists v Socrates (470-399BC)(470-399BC)

• Sophists: There is no truthSophists: There is no truth– Everything is in flux, everything is Everything is in flux, everything is

relativerelative– Skeptical that anything can be knownSkeptical that anything can be known– ““Man is the measure of all things” - Man is the measure of all things” -

ProtagorusProtagorus

SocratesSocrates

• Assumes objectivity…a rationalist…Assumes objectivity…a rationalist…

• There are unchangeable truthsThere are unchangeable truths…what are they? …what are they?

• The Power of Socratic dialogueThe Power of Socratic dialogue

• Euthyphro Reading…Euthyphro Reading…

SocratesSocrates

Recall 4 Views of Ethics:Recall 4 Views of Ethics:

•Non-Cognitive Theory: Boo/Yay Non-Cognitive Theory: Boo/Yay theorytheory

•Ethical Subjective TheoryEthical Subjective Theory

•Cultural Subjective TheoryCultural Subjective Theory

•Moral Objective TheoryMoral Objective Theory

Would Socrates Make a Would Socrates Make a Good Teacher at our Good Teacher at our School?School?

Plato: An Idealist Plato: An Idealist Answering Thales’ ProblemAnswering Thales’ Problem

Seeking a Unified Field Theory Seeking a Unified Field Theory to Explain Everythingto Explain Everything

Plato’s Theory of FormsPlato’s Theory of Forms

• Premise: Thales’ answer did not Premise: Thales’ answer did not include everything in the intangible include everything in the intangible world world

1.1. Material stuff changes and erodes Material stuff changes and erodes

2.2. Unchanging is the timeless ideas or Unchanging is the timeless ideas or moldsmolds

Plato’s Theory of FormsPlato’s Theory of Forms• These molds exist in intangible real of ideasThese molds exist in intangible real of ideas

• These immutable molds: called “forms”These immutable molds: called “forms”

• We relate to these “forms” through our We relate to these “forms” through our reasonreason

• The world of senses is transitory and The world of senses is transitory and subject to opinion via the sensessubject to opinion via the senses

True Reality is in the realm of True Reality is in the realm of IdeaIdea• It is immaterial and eternal and It is immaterial and eternal and

unchangingunchanging

• One cannot obtain true knowledge One cannot obtain true knowledge through the sensesthrough the senses– Physical world is a reflection of reality but Physical world is a reflection of reality but

not reality itselfnot reality itself

How do we locate reality?How do we locate reality?

• A rationalist approachA rationalist approach– Dialectical discussions of ideas Dialectical discussions of ideas – Push each idea, probe, questionPush each idea, probe, question– Locate errors and adjust thinkingLocate errors and adjust thinking

……This sounds like someone else we know…This sounds like someone else we know…

Man is a dual creatureMan is a dual creature

• Realm of formsRealm of forms– PermanentPermanent– realreal “a circle”“a circle”

• Realm of sensesRealm of senses– Soap bubbles – fluxSoap bubbles – flux– Poor reflectionsPoor reflections

circle

We are not born tabular rasa;we have latent knowledge of the realm of forms – we recognize types in this world because of inbredknowledge of forms…