Allegory of the Cave
Theory of Forms
Plato, Aristotle, Ockham
Which is which?
What are they doing with
their hands?
Where are they?
See the full painting here
Greek Philosophers (500BC – 200BC) Timeline
The
Great
Three
Plato, 20, meets Socrates, 60
Plato
(429 - 347)
500 BC
200 BC
Socrates
(469 - 399)
What is an allegory?
 It’s a story that teaches you about something other
than what is in the story.
What is an analogy?
 A comparison made to show a similarity.
Watch this YouTube video of the Cave Allegory
Read this excerpt from Plato’s Republic, Book VII, if you
prefer reading to watching
Plato’s Cave Allegory has a number of purposes:
1. distinguish appearance from reality
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it is possible to have the wrong understanding of the things
we see, hear, feel, etc.
2. explain enlightenment
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moving from ‘shadows’ to ‘the real’
involves pain, confusion
makes you an outcast
is a one-way trip
improves you, but
makes you a nerd
makes you mentally clumsy
cannot be taught, you must see for yourself
Plato’s Cave Allegory has a number of purposes:
1. distinguish appearance from reality
2. explain enlightenment
3. introduce the Theory of Forms (or Ideas)
the allegory provides for an analogy:
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as shadows are to physical things, physical things are to the
Forms (Ideas)
In virtue of what are these two things red?
It’s not the paint, dye, pigment, light waves, frequency of waves, etc., that
makes the circle on the left red, that makes the circle on the right red,
because all that stuff is over there (on the left) rather than over here
(on the right) … similarly, it’s not the paint, dye, pigment, light waves,
frequency of waves, etc., that makes the circle on the right red, that
makes the circle on the left red, because all that stuff is over here (on
the right), rather than over there (on the left).
So, in virtue of what are they both red?
Notice that ‘red’ is a singular term … the subject is plural, but the
predicate is singular! These are not ‘reds’. How can this be?!
How then, can two things be one thing?!
In virtue of what are these two things circular?
It’s not the curve of the border that makes the circle on the left circular
that makes the circle on the right circular, because that curve of the
border is over there (on the left) rather than over here (on the right) …
similarly, it’s not the curve of the border that makes the circle on the
right circular that makes the circle on the left circular because that
curve of the border is over here (on the right), rather than over there
(on the left).
So, in virtue of what are they both circular?
Notice that ‘circular’ is a singular term … these are not ‘circulars’!
How then, can two things be one thing?!
Plato thinks we need universals to account for our
knowledge. If, as Heraclitus said, the only thing real is flux
or change, then we couldn’t know anything (nothing our
thoughts were about would match our thoughts, since what
underlies our thoughts is always changing).
Consider the statement:
blue is darker than yellow
What would happen if every blue and yellow thing winked
out of existence? Would the statement be false?
Plato believed that these Forms, or Universals, are:
 Eternal
 Unchanging
 Necessary (exist [subsist?] necessarily)
If they were not so, ‘blue is darker than yellow’ and
the truths about geometry, and innumerable
others, could all be false. But, when you think hard
about them, they apparently cannot be false.
Qualities
 colors
 shapes
 sounds
 textures
 temps
 flavors
 odors
 aspects of all
 etc.
Relations
• lighter/dark
er
• rounder/squ
arer
• higher/lower
• rougher/smo
other
• sweeter/sour
er
• etc.
Kinds
• animal
• vertebrate
• human
• metal
• steel
• apple
• book
• sandwich
• etc.
Where are these Forms?
Because everything in space and time
 comes into being at some time and in some place, and
 goes out of being at some time and in some place,
the Forms, eternal and unchanging, must be outside
space and time.
Some call this place Plato’s Heaven
Some call the Forms Divine Ideas
Problem:
How do Plato’s non-temporal, non-spatial, eternal, unchanging
Forms interact with the temporal, spatial, temporary, changing
world of our experience?
Plato tells us: by a relation of ‘participation’ or ‘sharing’
Another way to say it, Forms are ‘instantiated’ in physical things.
 This red thing has an instance of redness,
 this ‘being in between’ is an instance of inbetweeness,
 this dog is an instance of dogness.
But, how do physical things participate in Forms? Or, how are the
Forms instantiated in things?
Aristotle rejected Plato’s Forms as entities that exist separate from
the things that instantiate them.
He held, instead, that the Forms exist only
 in re (in things), and
 not ante rem (not before things)
and, that we know them by lifting them out of sensible objects by
abstraction
 simple (just noticing a feature of something)
 common (recognizing two features are one and the same)
 precise (cutting off reference to all other features)
It is the last kind of abstraction Aristotle believes Plato uses,
illicitly, to derive his concept of separated Forms
There are Forms only for those qualities, relations, and kinds
that
 have existed,
 exist, or
 will exist
What it means to be a universal is to be ‘predicated of many’.
His emphasis on language led medieval commentators to
follow suit, and seemingly led to both
 Conceptualism (universals are concepts in the mind), and,
 Nominalism (universals are a mere ‘puff of voice’; universal
words)
William of Ockham (of Oak Hamlet, Surry, England) rejects both
Plato’s and Aristotle’s views about Universals.
Ockham is a Nominalist (some scholars now think he should be
considered a Conceptualist instead).
From Paul Spade’s Stanford article on Ockham:
He [Ockham] believed in “abstractions” such as whiteness and
humanity, for instance, although he did not believe they were
universals. (On the contrary, there are at least as many distinct
whitenesses as there are white things.) He certainly believed in
immaterial entities such as God and angels. He did not believe in
mathematical (“quantitative”) entities of any kind.
Ockham, from the Internet Encyclopedia of Philosophy:
There is no universal outside the mind really existing in
individual substances or in the essences of things…. The
reason is that everything that is not many things is
necessarily one thing in number and consequently a
singular thing. [Opera Philosophica II, pp. 11-12]
Ockham provides an argument to support his view … from
the Internet Encyclopedia of Philosophy, again:
…it would follow that God would not be able to annihilate one
individual substance without destroying the other individuals
of the same kind. For, if he were to annihilate one individual,
he would destroy the whole that is essentially that individual
and, consequently, he would destroy the universal that is in it
and in others of the same essence. Other things of the same
essence would not remain, for they could not continue to
exist without the universal that constitutes a part of them.
[Opera Philosophica I, p. 51]
Does this argument work equally well against both Plato’s
and Aristotle’s conceptions of universals?
If Ockham’s view is best characterized as ‘Resemblance
Nominalism’, or ‘Resemblance Conceptualism’, what
arguments weigh against it?
Read Rodriguez-Pereyra, if interested. (You are not
responsible for anything from this link)
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Socrates’ image: http://www1.fccj.org/cgroves/2211docs/2211test_3.htm
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Plato’s and Aristotle’s images: http://heritage-key.com/blogs/malcolmj/top-10-ancient-greek-philosophers