The-Idea-Theory

advertisement
The Idea Theory
The Conformal Theory
Aristotle
• Lived in Greece 384-322 BCE
• Student of Plato at the Academy
• Taught Alexander the Great
• Started his own school, the
Lyceum
• Towering figure in Western
philosophy and Christianity
• According to Aristotle, substances
are composed of matter + form.
Hylomorphism
Greek words ‘hule’ (matter) + ‘morphe’ (form)
The doctrine is sometimes called Aristotle’s matter-formism.
Introduced to understand some issues with identity over time.
What’s the Same? What’s Different?
Essential vs. Inessential Form
Aristotle’s Psychology
The soul is the form of the body.
Asking whether the soul = the body
is like asking whether the bronze
statue = its shape.
Maybe, maybe not, but it’s not of
deep philosophical importance.
The Heirarchy of Ensouled Beings
Intellectual Soul
Perceptual Soul
Nutritive Soul
The Conformal Theory
When an animal perceives a thing,
“it is made like it and is such as that
thing is” (De Anima ii 5, 418a3–6).
Aristotle also holds a similar view,
identifying the form of the knower
and the thing known.
This is an obscure doctrine.
Conformal Theory: Literal Interpretation
Perceives
Conformal Theory: Literal Interpretation
Perceives
Linguistic Representation
Aristotle thought that spoken
language was an outward sign of
the state of one’s soul.
So the (spoken) word ‘house’ was a
sign of my soul having the form of a
house.
Linguistic Representation
So we can say that ‘house’
represents houses, because it is a
sign of a state of my soul that
represents houses (by identity of
form with them).
Some Problems
• [First let students talk.]
• If my eyes have the same form as a house when I see a house, how
come people looking at my eyes don’t see houses?
• If my eyes have the same form as a house when I see a house, and
having-the-same-form is representing/ perceiving, then how come
the house doesn’t represent/ perceive me.
• If I’m looking at your eyes and you’re looking at my eyes, what form
do our eyes have?
Aquinas and the Conformal Theory
• St. Thomas Aquinas (1225-1274 CE)
• Doctor of the Church, Catholic
Church’s greatest theologian and
philosopher.
• Tried to synthesize Aristotle with
Christianity.
• Tried to elaborate the conformal
theory and deal with some of the
problems.
Aquinas and the Conformal Theory
Elaboration of the theory:
The house-form was not “really”
present in my eyes, it was only
“spiritually” present.
Spiritually present forms represent
really present ones, but not vice
versa.
Conformal Theory: Aquinas’ Interpretation
Spiritual Form
Real Form
Perceives
Does That Solve The Problems?
• If my eyes have the same form as a house when I see a house, how
come people looking at my eyes don’t see houses?
• If my eyes have the same form as a house when I see a house, and
having-the-same-form is representing/ perceiving, then how come
the house doesn’t represent/ perceive me.
• If I’m looking at your eyes and you’re looking at my eyes, what form
do our eyes have?
New Science, New Problems
The 17th Century saw the rise of corpuscularianism.
It was a lot like Greek atomism, except whereas atoms are essentially
indivisible, corpuscles could theoretically be divided.
Notable corpuscularians were…
Robert Boyle, 1627-1691
Isaac Newton, 1643-1727
Thomas Hobbes, 1588-1679
John Locke, 1632-1704
John Locke
• Father of Classical Liberalism
(civil liberties, economic
freedom, limited government)
• Along with Descartes, most
important 17th Century
Western philosopher.
• Worked in Boyle’s lab.
Corpuscularianism
The view was that everything is made out of corpuscles– microscopic
little bits that had a certain shape, size, and momentum.
Corpuscularianism
However, the corpuscles did not have color, taste, smell, sound, or
warmth. These other qualities were explained as the effects of the
corpuscles on our sensory organs.
For example, heat is just the motion of corpuscles, but this motion
causes us to experience the sensation of warmth.
The Unreality of Tastes, Colors, etc.
“I think that tastes, odors, colors, and so on are no more than mere
names so far as the object in which we place them is concerned, and
that they reside only in the consciousness.
Hence if the living creature were removed, all these qualities would be
wiped away and annihilated” (Galileo, The Assayer).
Galileo, The Assayer
“I think that tastes, odors, colors,
and so on are no more than mere
names so far as the object in
which we place them is
concerned, and that they reside
only in the consciousness.
Hence if the living creature were
removed, all these qualities would
be wiped away and annihilated”
Problems for the Conformal Theory
But if colors, for example, exist only in the mind, then it cannot be true
that when I represent a white horse, my soul has the same form as a
white horse.
There are no white horses. There are horses that cause me to
experience whiteness when light bounces off of them. But the
whiteness itself depends on me, the observer. Whiteness exists only in
minds.
The Idea Theory
Macbeth, Act I, scene i
Is this a dagger which I see before me,
The handle toward my hand?
Come, let me clutch thee.
I have thee not, and yet I see thee still.
Art thou not, fatal vision, sensible
To feeling as to sight? or art thou but
A dagger of the mind, a false creation,
Proceeding from the heat-oppressed brain?
Hallucinations
Normally we talk as though we see physical things, out there in the
world. “I see a dagger”– a dagger is obviously not mental. But what do I
see when I hallucinate a dagger?
Ideas
A popular view among 17th and 18th Century Western philosophers was
that what you really saw was ideas– mental things.
On this view, ideas were something like little colored pictures in the
mind.
Idea Theory
Mind
Idea of a
Dagger
Dagger
Hallucination
Mind
Idea of a
Dagger
No Dagger
Indirect Realism
Views of this general form are called “indirect realism.” What you
directly see are mental entities (for example, ideas). You only indirectly
see the real things that the ideas represent.
Indirect realism allows us to maintain that there’s an appearance-gap
between what we see (ideas) and the things that the ideas represent.
Resemblance Theory
According to the resemblance theory of representation, ideas
represent things by resembling them– sort of like how painting works.
Painting
The Nature of Ideas
According to Locke, ideas are “the
pictures drawn in our minds”
(Essay, II.x.5).
The Nature of Ideas
An idea of a horse, then, is very
much like a picture, image, or
painting of a horse.
Compare Hume: “By ideas I mean
the faint images of [perceptions]
in thinking and reasoning”
(Treatise, I.i.1).
Resembles
Sees
Mind
Idea of a
Dagger
Dagger
Resemblance
This means that even though what you see are ideas, the ideas are
close copies of the real things, the way a realistic painting is a close
copy of a scene.
Corpuscularianism Revisited
So how do we handle the fact that the world isn’t colored?
Partly
Resembles
Sees
Mind
Idea of a Dog
Dog
Note
This was already really part of the original resemblance theory…
nobody thinks your idea of a dog smells like a dog!
Terminology
Locke called properties like shape, size, and motion– properties that
both ideas and real things could have– primary qualities.
Other properties that only ideas had were called secondary qualities.
Locke on Language
“Words are sensible signs,
necessary for communication of
ideas. Man, though he have great
variety of thoughts, and such
from which others as well as
himself might receive profit and
delight…”
Locke on Language
“yet they are all within his own
breast, invisible and hidden from
others, nor can of themselves be
made to appear…”
Locke on Language
“The comfort and advantage of
society not being to be had
without communication of
thoughts, it was necessary that
man should find out some
external sensible signs, whereof
those invisible ideas, which his
thoughts are made up of, might
be made known to others.”
Problems #1: Abstract Ideas
George Berkeley (1685-1753)
Locke on General Terms
“It is not enough for the
perfection of language,
that sounds can be made
signs of ideas, unless
those signs can be so
made use of as to
comprehend several
particular things…”
Locke on General Terms
“…for the multiplication of
words would have
perplexed their use, had
every particular thing
need of a distinct name to
be signified by…”
Locke on General Terms
“To remedy this
inconvenience, language
had yet a further
improvement in the use of
general terms, whereby
one word was made to
mark a multitude of
particular existences.”
Particular Terms
Locke
General Terms
Dog
Abstract Ideas
If we accept the idea theory, then, we have to accept that there are
“abstract ideas”– not mental pictures of a particular person, but mental
pictures that resemble equally a group of things.
These abstract ideas are the meanings of general terms.
Berkeley vs. Abstract Ideas
Berkeley, however, argues that abstract ideas are impossible.
The abstract idea of a man is supposed to apply equally to a tall man
and a short man; a black man and a white man; a skinny man and a fat
man; well-dressed man and a pauper, etc.
But no picture resembles equally all such men, as any picture of a man
depicts him as either skinny or fat, but not both and not neither.
Problem #2: The Determinacy of
Thought
Wittgenstein’s Man on the Hill
“A picture which corresponds to a
man walking up a hill forward
corresponds equally, and in the
same way, to a man sliding down
the hill backward.”
-- Philosophical Investigations
Wittgenstein’s Man on the Hill
“Perhaps a Martian would
describe the picture [as the man
sliding down]. I do not need to
explain why we do not describe it
so.”
Representation can be more
determinate than resemblance.
Seeing vs. Seeing-as
What the Necker cube example suggests is a more general problem.
You can look at the Fischer cow and not see that it is a cow. When you
see the picture as a cow, your perception changes.
But if your idea of the picture is just a copy of that picture in your head,
what about it changes such that once it was just squiggles and then it’s
a cow?
Problem #3: Error
Representation and Error
On the Idea Theorist’s view, I can only represent a thing if I have a
mental image that sufficiently resembles it.
But there seem to be lots of things that we can think about, while
being massively in error about.
Advertisements vs. Reality
Problem #4: The Structure of
Resemblance
Equivalence Relations
Resemblance as an Equivalence Relation
Resemblance, like identity, is an equivalence relation, meaning it’s
reflexive, symmetric, and transitive:
• Reflexive: for all X, X resembles X. (Everything resembles itself.)
• Symmetric: for all X and Y, if X resembles Y, then Y resembles X.
• Transitive: for all X, Y, and Z, if X resembles Y and Y resembles Z, then
X resembles Z.
Problem for the idea theory: resemblance is an equivalence relation,
but representation is not. Therefore representation ≠ resemblance.
1. Representation is Not Reflexive
You can have a representation
that represents itself (for example,
a map that includes the map’s
location), but most
representations don’t represent
themselves.
You can have a painting of a horse,
that is not a painting of a painting
of a horse (not a painting of itself).
2. Representation is Not Symmetric
Most of what gets represented is not representational. My thoughts
represent lakes and rivers and trees, but lakes and rivers and trees
don’t represent my thoughts.
And even when I do represent representations (when I think about a
painting, say), usually they don’t represent me or my thoughts.
3. Representation is not Transitive
The directory at the museum might represent the location of a certain
Picasso painting. That painting could represent a horse. But the
directory doesn’t represent any horses, it only represents paintings.
Problem #5: Truth-Evaluability
Concepts
Concepts are representations of things or qualities: so I can have a
concept of Obama, or a concept of red, or a concept of a horse, or a
concept of a concept.
Importantly, concepts are not truth-evaluable. My concept of red isn’t
true, and it isn’t false either. It might be more or less accurate.
Propositions
We can say that when I think of a thing, or think about a thing, then I
am entertaining a concept.
However, when I think that such-and-such, I am entertaining a
proposition.
Propositions
For example, I can think that Obama is the US president, or think that
grass is red, or think that the concept of a horse is not a concept.
Propositions are truth-evaluable: when I think that grass is red, my
thought is false. (Not so when I just think of red.)
The idea theory seems to have trouble distinguishing concepts and
propositions.
According to the idea theory, thought is having ideas, and ideas are like
mental pictures. Are mental pictures truth-evaluable? If they are, then
concepts aren’t ideas. If they aren’t, then propositions aren’t ideas.
Download