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Copyright © 2011 Pearson Education, Inc. All rights reserved.
Copyright © 2011 Pearson Education, Inc. All rights reserved.
READING CRITICALLY: HOW DO YOU KNOW WHAT IS “REAL”?
After reading the Russell essay, look closely at a piece of furniture that is within your field of vision: Is the piece of furniture real? How do you know if it’s real or not? Explain your reasoning for both responses.
Russell analyzes the table near him in terms of its color, texture, and shape, and concludes:Thus it becomes evident that the real table, if there is one, is not the same as what we
immediately experience by sight or touch or hearing. The real table, if there is one, is not
immediately known to us at all, but must be an inference from what is immediately known.
Do you agree with Russell’s conclusion? Why or why not?
Russell goes on to observe: “Hence, two very difficult questions at once arise; namely, (1) Is there a real table at all? (2) If so, what sort of object can it be?” Explain how you would respond to these two questions, and explain the reasoning behind your conclusions.
Russell’s essay emphasizes the significance of the philosophical distinction between appearances (what things seem to be) and reality (what they are). After “thinking philosophically” about these issues, do you see the world around you in a new light? Explain your response and your reasons for it.
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LOCKE VS. LEIBNIZ ON INNATE IDEAS
LOCKE: AGAINST INNATE IDEAS The argument from universal consent for
innate ideas is inconclusive Children and “idiots” do not have innate
ideas It is impossible to have ideas of which we
are not conscious
LEIBNIZ’S REPLY TO LOCKE Sense experience alone cannot
validate general principles or laws We do know things that are not
immediately before our perception There is extensive evidence that we
have innate cognitive structures
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LOCKE’S CAUSAL THEORY OF PERCEPTION: ELEMENTS OF THE KNOWING PROCESS
The entity or object in the world
Sensations (sense data, images, sensory impressions) emitted by the objects via “impulses” and transmitted to our five senses
Ideas, which Locke characterizes as “the immediate objects of perception, thought, or understanding”—in other words, the images or impressions produced in our minds by the impulses emitted by the objects
The human subject, knower, or conscious mind who is able to perceive the ideas in his or her mind and “reflect” on them, thus constructing knowledge
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PRIMARY AND SECONDARY QUALITIES
Primary qualities “resemble” (or “reside in”) an object even when we are not perceiving the object Solidity Extension Figure (shape) Motion or rest Number
Secondary qualities do not “resemble” (or “reside in”) an object, but are “powers” of objects to produce sensations in our minds Colors Sounds Tastes Odors
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GEORGE BERKELEY: “TO BE IS TO BE PERCEIVED”
There is no such thing as material substance; all that exist are “minds” and “ideas”
There is no distinction between “primary” and “secondary” qualities
What we mistakenly believe to be “material objects” are really collections of ideas in the mind of God
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The Fate of Empiricism
With the success of Newtonian physics and Locke’s account of an empiricist metaphysics and epistemology Empiricism seemed to clearly have the upper
hand against rationalism Hume comes along and shows that there is
something deeply troubling about empiricism It leads to a radical kind of skepticism
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Hume’s Version of Empiricism
Contents of the mind can be divided into two categories Impressions-- the actual experiences that we
have Tasting an apple, seeing a sunset, feeling pain,
or angry or jealous, hungry or sad, etc Ideas– Copies of impressions My memory of the taste of the apple, my idea of
anger, jealousy, hunger, red
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Perception
Impressions and ideas are each a kind of perception for Hume they are distinguished by their ‘force and
vivacity’ Impressions are ‘our more lively perceptions’ Ideas (or thoughts) are dull and lifeless copies of
the original impression This means that both are merely mental
phenomena
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The Empiricist Theory of Meaning
Words in language stand for ideas Hume endorses Locke’s distinction between
simple and complex ideas Complex ideas are composed of simple ones
Simples ones either can be traced back to an impression from which they were copied
Or else they are meaningless nonsense If an idea cannot be traced back to an
impression it is meaningless and should not be used
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Empiricist Epistemology
Human knowledge falls into two kinds for Hume Relations of Ideas– all a priori knowledge Matters of Fact– all empirical knowledge
To decide which is which you apply the following rule If the negation of the proposition in question is a
contradiction then it is a Relation of Ideas If not, a Matter of Fact
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RoI & MoF Relations of Ideas Matters of Fact
All bachelors are unmarriedAll bachelors are messy
All triangles have three sides
All dogs have four legs
The sun will rise tomorrow
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RoI & MoF
Relations of Ideas All bachelors are
unmarried All triangles have three
sides A2+B2=C2 (3 x 5)=(1/2 x 30) For any sentence S,
either S is true or S is false
S can’t be true and also not true at the same time
Matters of Fact All bachelors are
messy All dogs have four legs Apples are red Rent in NYC is
expensive Subway fare is $2.00 Fire causes pain Objects when dropped
will fall The future will
resemble the past
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RoI
Relations of ideas consists of two parts Ideas And the relations between them E.g. my ideas BACHELOR and UNMARRIED MALE
are related in such a way as to make it impossible for there to be a married bachelor
This is true for all relations of ideas Their truth is independent of experience in the
sense that one does not need to go and check to see if they are true
Mathematics and logic are purely formal systems of inter-related definitions
Numbers do not need to exist to make it true that 2+2-4
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MoF
Matters of Fact on the other hand have their truth determined by the way that the world happens to be
Hume argues that the idea of cause and effect is a MoF because it fails to meet the two criteria of something that is a priori To deny it is not a contradiction We cannot, without experience, predict what the
effect of any given cause will be
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Cause and Effect
If c&e is a MoF then what impression does it derive from?
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C & E II
The idea of causation is the idea of a necessary connection between events To say that the connection is necessary is to say
that the same effect will always follow from the same cause
We do not get the idea of necessary connection from reason
And we do not get it from experience We never see the necessary connection
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Meaningless
Since this idea cannot be traced back to an impression it is meaningless
We have no rational reason to expect any given cause and effect relation to hold in the future
All of our inductive knowledge is founded on our belief that the future will resemble the past
But this belief is completely irrational Meaning we have no rational basis to believe it
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Summary of the Argument so Far
All human knowledge is either learned from experience (matters of fact) or from reason (relation of ideas)
MoF are composed of ideas copied from impressions and are true or false depending on the kind of experience we have ‘dogs can fly’ vs. ‘dogs don’t like cats’
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The Argument II
RoI are true or false depending on the relations that hold between the ideas ‘triangles are four-sided objects’ vs. ‘triangles
have three sides’ We can tell the difference between these by
seeing what happens when we negate the sentence in question If it is a contradiction it is a RoI, if not a MoF
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“HUME’S FORK”: RELATIONS OF IDEAS AND MATTERS OF FACT
Relations of Ideas Mathematical statements, such as those
found in geometry, algebra, and arithmetic
Tautologies, or logical truths, such as “A dog is a dog”
Known by reason To deny them is to contradict oneself;
therefore, they give us absolute certainty But they have no empirical content
Matters of Fact Involve sense experience It is possible to logically contradict a
matter of fact Hume believes that if a claim of
empirical knowledge cannot be reduced to a relation of ideas or a matter of fact, it should be discarded as knowledge. He challenges: Any necessary connection between cause
and effect
The notion of material substance
The notion of mental substance (“soul”)
Inductive reasoning
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The Argument III
All of our ideas must come from one of these two sources
One of the most important ideas we have is the idea of causation The idea of a necessary connection between
events Same cause=same effect EVERY TIME
All of science is based on this idea All of our common sense knowledge about the
world based on this idea
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The Argument IV
So, where does it come from? Not RoI To deny any causal relation is not a
contradiction It is always possible to imagine something else
happening But we can’t imagine a square circle
We have to go and check We can’t tell what causes what without
experience
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The Argument V
So, it must be a MoF That means that the idea of necessary
connection must be traceable back to an impression
Otherwise it is a meaningless idea But when we look at any example of A causing
B all we see are separate events We see A happen (the pool stick hits the ball) Then we see B happen (the second ball moves)
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The Argument VI
We do not see anything that connects the two events There is nothing that we can point to and say
that it is the thing that makes the second event the necessary consequence of the first event
So, Hume concludes, we have no rational reason (i.e. based on our experience or reason) to believe that the laws of physics are necessary and universal
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The Argument VII
All inductive knowledge is based on the fallacy of assuming that the future will resemble the past But just because something has happened for a
long time is no guarantee that it will always happen
So, the sun may have risen everyday so far, but who can say with certainty that it will rise tomorrow?
Just like problem of black swans
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Habit
So where does the idea come from? It comes from ‘a habit of expectation’
We see A happen We see B happen right after We see A happen We see B happen right after This is repeated Soon when we see A happen we come to expect
that B will happen right after
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Spreading the Mind
It is the subjective feeling of expectation that we mistakenly ‘project’ out onto the events that we observe
We cannot know if there is anything more to the word than this This is an epistemological claim: we can’t know if
there is a necessary connection between events NOT a metaphysical claim: There is no necessary
connection between events
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Pavlov & Classical Conditioning
We have been trained by nature to expect certain events upon seeing certain other events Just like Pavlov’s dog
You ring the bell and bring some food The dog salivates Repeat Soon the dog salivates when hearing the bell
whether or not food comes The dog has come to expect ‘bell then food’
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Classical Conditioning II
Now if the dog were to reason to itself as follows, Every time the bell has rang food has appeared This has happened everyday of my existence,
every since I was a puppy I can infer from this that the next time the bell
rings, food will appear We could easily see that the dog has made a
mistake
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Classical Conditioning III
There is no necessary connection between bell ringing and food appearing in nature How can we tell that this is not the way nature is
in reality? Nature is regular (so was the bell ringing/food
bringing relationship) Things so far have happened regularly and
predictably But we have no reason to believe that it must
continue
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READING CRITICALLY: ANALYZING HUME’S CASE FOR SKEPTICISM
Is Hume correct to call the appeal to God’s existence to support the existence of an external world “philosophical hypocrisy”? Why or why not?
Summarize Hume’s arguments against certain knowledge of the principle of cause and effect. Do you agree with his reasoning? Why or why not? Construct an alternative argument to convince Hume that the principle of cause and effect is valid and give examples.
Would your agreeing with Hume’s critique of knowledge claims about cause and effect and induction change the way you live your life? Why or why not?
Hume splits his practical life from his theoretical philosophical commitments. Do you agree that such a split is possible? Should our choices in life reflect our epistemological convictions? Describe an example to support your point of view.
Hume believes that all metaphysical beliefs (that is, any belief not based on direct sense experience) should be “committed to the flames” because they cannot be empirically justified. This would include all beliefs regarding God, human freedom, universal moral laws, and so on. Do you agree with Hume? If not, how would you rebut his arguments?
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KANT’S “COPERNICAN REVOLUTION”
“Hitherto it has been assumed that all our knowledge must conform to objects. But all attempts to extend our knowledge of objects by establishing something in regard to them by means of concepts have, on this assumption, ended in failure. We must, therefore, make trial whether we may have more success if we suppose that objects must conform to our knowledge.” –Critique of Pure Reason
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Kant’s Dogmatic Slumber
Kant is disturbed from thinking that everything in science is fine by Hume’s argument Empiricism cannot deliver necessary truths ‘experience can teach us that something is the
case but it cannot teach us that it must be the case’
Yet science claims to discover necessary truths about nature Even worse, Hume claimed to have shown that
Human Beings are essentially irrational
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Transcendental Idealism
Kant agrees with Hume that we cannot learn that the causal relation is necessary and universal from experience But Hume has not shown that we can’t have a
priori knowledge For Hume something was a priori if we could
not deny it without contradiction For Kant something is a priori if is knowable
completely independently of experience
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An Analogy
Suppose that I told you that there were 25 people in a room on the second floor of some building What could you know about that room? Quite a bit actually Its size, what it was made out of, etc.
Kant’s strategy is similar He wants to know what we can know given that
our experience is the way that it is
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The Structure of Experience
How could our experience be the way that it is?
How is it? Objects are located in space and time Can you imagine an object which was not at any
place? No
This is something that we can know a priori It is not dependent on experience
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Conditions of all Possible Experience
It is the pre-condition for any experience at all Just like space in the room is a precondition of
having objects in the room So too space is a necessary condition of any
possible experience Thus we can know with absolute certainty that
whatever experiences we do have They will all take place at some time and at
some particular place
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The A Priori
So Kant concludes that there is pure A priori knowledge ‘pure’ because it does not depend on experience But is rather the pre-conditions for any possible
experience It is necessary
It is not possible to have experience without space
And universal All experiences will be in space
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Analytic vs. Synthetic
An analytic truth is one that is true by virtue of the meaning of the words themselves All bachelors are unmarried males They do not add to our knowledge
Synthetic truths are true in virtue of the kind of experience we have All bachelors are messy They do add to our knowledge
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Hume’s Mistake
Hume’s criterion for being a priori P is a priori if the denial of p is a contradiction
Let him divide all of our knowledge into that which was necessary (RoI) and that which was contingent (MoF)
Kant argues that we really have four categories
Analytic & A priori– truths which are true by definition and also necessary and universal All analytic truths are a priori
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Hume’s Mistake II
Analytic & A posteriori– truths which are true by definition but also discovered by experience Kant denied that there were any such truths
Synthetic A posteriori– Adds to our knowledge and learned from experience
Synthetic A priori– Adds to our knowledge and also necessary and universal Hume denied that there were any such truths That was his mistake
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Kant’s 4 Distinctions
A Priori A Posteriori
Analytic
Synthetic
All Bachelors are unmarried
malesAll triangles have three
sidesDogs bark
Apples taste good
7+5=12
???????
Cause & effect
!!!!!!
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Synthetic A Priori Knowledge
So Kant’s answer to Hume is his theory of synthetic a priori knowledge Take ‘fire causes pain’ It is synthetic, it adds to our experience But it is also a priori, that is, necessary and
universal It is a priori in the sense that we can tell by
looking at the structure of our experience that it must be a certain way This Kant calls phenomena
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Phenomena vs. Noumena
The phenomenal world is the world as it appears to us. It is the world that we see touch taste etc.
The noumenal world is the way that the world is in-itself The world as it is when no one is looking at it
All we can know is the way our experience of the world will be We can’t know the noumenal world
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Phenomena v. Noumena II
NoumenaUnderstanding
Sensibility
HiWasup?
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Kant’s Philosophy of Mind
The mind has two components Sensibility Understanding
Sensibility takes in ‘raw’ unorganized noumena and organizes it into phenomena (our experience) Each has their categories that they use in order
to construct our experience The sensibility has Space and Time
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Kant’s Philosophy of Mind II
The understanding has 12 categories Unity, plurality, totality, reality, negation,
limitation, substance/property, cause & effect, community, possibility/impossibility, existence/non-existence, and necessary/contingent
With these categories, and the two from the sensibility, our mind constructs our experience We can know with absolute certainty that our
experience will conform to the categories
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Kant’s Philosophy of Mind IV
That is the only way that experience like ours is possible The same cause must bring about the same
effect or else our experience would be like a dream
Now here, now there… Yet this comes at a heavy cost
Science studies our experience of the world It does not, cannot, study the noumenal world How can I every talk to you?
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Phenomena v. Noumena III
HiWasup
?
HiWasup
?
MeYou
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Kant’s Philosophy of Mind V
Kant called this a Copernican Revolution in philosophy Instead of the mind passively acting like a
recorder of an outside reality Kant sees the human mind as actively
constructing reality This is his mix of Rationalism and Empiricism
Empiricism– science is synthetic knowledge Rationalism– but based on a priori categories
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KANT ON THE SYNTETIC A PRIORI AND THE PHENOMENAL AND NOUMENAL WORLDS
THE SYNTHETIC A PRIORI Necessary and universally true
a priori—can be discovered independently of experience
Synthetic in the sense that it provides us with genuine information regarding our experience in the world
THE PHENOMENAL AND NOUMENAL WORLDS
phenomenal reality is the world as we constitute it and experience it
noumenal reality is the world beyond our perceptions, reality “in-itself”
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APPLYING KANT’S THEORY: THE ASSASSINATION OF MALCOLM X
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ALLISON JAGGAR: EMOTIONS SHAPE OUR UNDERSTANDING
Jaggar believes that the “new science” of Newton and Galileo spawned a wide split between reason and emotion, so that “dispassionate” reason was considered the only source of knowledge
She argues that “dispassionate investigation” is a myth, and that emotions should be incorporated into our epistemological framework, including the framework of scientific knowledge