Great Philosophers of Ancient
Greece: Plato and Aristotle
James A. Van Slyke, Ph.D.
Two Philosophers
Plato (428-348 B.C.)
Born into wealth and political power
Rejected a political career after the
death of Socrates
Socrates’ student
His school, The Academy, located next
to his house
Taught both academics and political
leaders
Died at the age of 81 at a wedding
feast
Two Philosophers
Aristotle (384 -322 B.C.)
Born in Macedonia 15 years after
Socrates’ death
In 367 B.C Aristotle at the age of 17
moved to Athens and studied at The
Academy for 20 years
Tutored Alexander the Great
Aristotle later set up his own school,
The Lyceum, outside of Athens
Great library and students
Many free lectures
Theory or Common sense?
 Plato
Pointing
towards the sky
Emphasized
theoretical
knowledge
Clothed in red
the volatile
element of fire
 Aristotle
Feet firmly on
the ground
Clothed in the
colors of green
(earth) and blue
(water)
Emphasized
the empirical,
what can be
demonstrated
and observed
Plato’s Thought
The Republic (written 375 B.C.)
Sought a definition of Justice
Explores several definitions
Statement of the aims of The Academy
Characters
Socrates – Narrator
Glaucon and Adeimantus
Primary respondents, elder brothers of Plato
Thrasymachus
Sophist
The Republic
Definitions of Justice
Objection of Thrasymachus
Justice is not virtue, but foolishness
Used for the interest of the powerful
Self-interest is more important than morality
Objections of Glaucon and Adeimantus
Means to avoid punishment
Gain a good reputation; social approval
Plato tries to show that justice is a good to be sought for
its own reward
The Republic
To understand justice, the philosopher must
understand “the form of the good”
Forms –
Idea or Essence of something
That which unites things into a particular category
Theory of Ideas
The allegory of the sun
The allegory of the cave
Philosopher is sent to rescue people from the cave
From the world of appearance to the reality of the good
The Republic
Plato’s society has three classes
1. Ruling class – soldiers
Selected through competition
Philosopher Kings
2. Auxiliary soldiers
Carried out necessary functions
3. Farmers and Artisans
Gave consent to rulers
Virtuous city is based on a proper division of labor
The Republic
Inner soul is similar to the division of labor in the city
Reason
Rules over the tempers and appetites
Tempers
Fight and punish
Anger
Appetite
Sexual desire
Hunger, thirst
The Republic
Justice is an individual in harmony with the three parts
of the soul; discord leads to injustice
A proper balance of the soul is based on the exercise of
reason
This leads to a just person and a just society
Thus, justice or goodness is its own reward
Better to fill the soul with understanding rather than
simply fulfilling the appetites
Justice or goodness leads to a healthy soul and a
healthy life
The Republic
Education
Imagination
Poets and Drama, story
Beliefs
Establishing a contingent fact
Mathematics
Abstract numbers
Geometrical proofs
Dialectic (philosophical) reasoning
proposes a hypothesis and
tries to show that it leads to a contradiction or elenchus if
successful the hypothesis is refuted
Tries to reach a premise that is unquestionable
Plato’s Cosmology
Form of the Good
Forms
stars/planets = divinities
humans
animals
plants
inorganic material
more order, goodness, beauty, less corruptibility as we go up the hierarchy
Aristotle
More interested in the empirical
Classification of animal behavior
Theories of causation
Efficient causation – sculptor
Material cause - stone
Formal cause – forms
Final cause – function something serves
Expanded and reformed Plato’s thought
Hylomorphic view of matter
Form and matter work together; interdependent
Aristotle
Understanding of the soul
Hierarchy of the soul
Different types of souls provide different functions
plants have vegetative/nutrition – about nutrient,
reproductive, grow
animals have animal/sensitive – sensation, locomotion,
humans rational soul – intellect