Transcript Plato and Aristotle

Plato
Plato
• Born in Athens in 428 or 427 BC, died at 80
in 348 or 347 BC. Youngest of 3 children
(all male). Aristocratic and politicallyconnected family. Father descended from
Athenian kings; died while Plato was
young. His mother remarried an associate of
Pericles’.
• Plato had political ambitions, but became
disillusioned with Athenian politics
– Empire in decline since the Peloponnesian war several
yrs before Plato was born
– Tyrannical junta ca 400 BC seized estates and executed
many.
– P witnessed trial/execution of Socrates in 399 BC in a
restored democracy on charges of corrupting youth,
introducing new gods, atheism, etc.
• Plato became thoroughly jaded, left Athens, gave up political
career, and traveled around the Mediterranean (Italy, Sicily,
Egypt)
• Studied religion, geometry, astronomy and composed first of
Dialogues
• Returned to Athens in 387 and founded the
Academy (possibly the first European
university) and taught astronomy, biology,
math, political theory, philosophy) until
closed around 1000 yrs later (529 AD) by
Justinian. Sought to train “philosopherkings”.
• Major Themes that form basis of his interest in matters of
psychological concern
– Wanted to find knowledge about which he could be certain
– Wanted to demonstrate the immortality of the soul
• Conceived of a world of phenomena and a world of forms (ideas)
– Phenomena: changing, essentially unreal world of appearances
– Forms: world that is real and eternal
– E.g., a perceived tree is only an appearance. Form of the tree, not
perceived directly, is known only intuitively—but this is what truly
exists
• Ideas not created by thought; an idea is reality, not thought
• World of appearances is just a shadow – example of the cave
• Independent existence of forms shown by
the phenomenon of reminiscence
– E.g., Socrates’ elicitation of geometry solution
from untutored slave boy. Since boy could
solve problem under questioning, he most have
already known the answer and that knowledge
of the forms had been present since birth.
– I.e., learning is the drawing-out of what’s
already there.
• Soul
– Means by which man apprehends the forms
– Only the soul is capable of knowing intuitively
the world of forms
• Theory of forms influenced P’s attitude
toward science
– Distrust of physical world, incl. Sensory
experience
– Turned away from empirical science
– Saw science as rationalistically drawing
conclusions from axioms
• Truth known only through introspection
• Only knowledge of the forms can give us truth
• Plato’s views suggest that soul and body are
fundamentally different
– Soul may apprehend an ideal world; not dependent on
the body (e.g., senses) and survives death of body
– (Note: same issue crops up again in medieval times;
called the problem of universals.
• Eye can see one cat at a time, but mind “knows” of the
universal cat”.
• Such knowledge assumes a knowing faculty that isn’t sensory.
– Thus, this knowledge is not given in experience.
– It is knowledge that mind must have prior to experience in order
that experience can teach us anything.