Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Make your likes visible on Facebook?

Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.

No, thanks

Unit 1: Logic and Critical Thinking

No description
by

Dan Lowe

on 19 July 2016

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Unit 1: Logic and Critical Thinking

Unit 1:
Thinking Logically
"How to Read Philosophy"
Criticizing Arguments
III. Review of the Syllabus
In-Class Policies
No laptops
No cellphones
If you have a cellphone or laptop out during class, then I'll ask you to leave. It won't affect your grade in any way -- but you just can't stay.
Your Grades
30% - Reading Quizzes
40% - Writing Assignments
About 15 (each class you have reading there is a 50% chance you will have a reading quiz)
2 Assignments (each worth 20%)
We have a day and a half explaining how to write each.
An
argument
is a series of statements, where a conclusion is supposed to be logically supported by premises.
What Validity Is
An argument is
valid
, when: if the premises are true, then the conclusion has to be true.
Some Examples
Clarification 1
An argument can be valid even if one (or all!) of the premises is false.
Validity = "
If

the premises are true, then the conclusion must be true."
Why Validity is Important
Recall the two main ways of criticizing an argument:

1. The things that are said in the argument aren't true.
2. The things that are said in the argument don't show that the conclusion is true.

If an argument is invalid, then you're criticizing it in the second way.

Some Practice Understanding Validity
1. If someone is enrolled in this class, then they are a CU student.
2. KR is a CU student.
C. Therefore, KR is enrolled in this class.
An argument is
sound
when
(1) it is
valid
, and
(2) it has
only true premises
.

What Arguments Are
V. Validity
The Concept of Validity
A Test to Figure out if an Argument is Invalid
1. All Chihuahuas are dogs.
2. All dogs are mammals.
C. Therefore, all Chihuahas are mammals.
Example 1
Valid!
1. Either he is dead or alive.
2. He is not alive.
C. Therefore, he is dead.
1. The sky is blue.
2. Barack Obama is president.
C. Therefore, Boulder is in Colorado.
An example of a valid argument:

1. Barack Obama is a fish.
2. All fish are from outer space.
C. Therefore, Barack Obama is from outer space.
1.
There are no tigers around this rock.
C.
Therefore, this rock keeps away tigers.
1. If you are in Colorado, then you are in Canada.
2. You are in Colorado.
C. Therefore, you are in Canada.
Example 2
Valid!
1. A fetus is a human being.
2. Abortion ends the life of a fetus.
C. Therefore, abortion violates a fetus's right to life.
Example 3
Our Test:
If there's an important term in the conclusion that's not in the premises, it's probably invalid.
Example 4
Invalid!
The first premise is false, but whether a premise is actually true or false is irrelevant for validity!
Invalid!
Some Practice Understanding Soundness
VI. Soundness
The Concept of Soundness
1. All Chihuahuas are dogs.
2. All dogs are mammals.
C. Therefore, all Chihuahas are mammals.
Example 1
Sound!
Example 2
Unsound!
Example 3
Premises true?
What Soundness Is
Examples of Unsound Arguments
If you are in Denver, then you are in Colorado. You are in Colorado. Therefore, you are in Denver.
Valid? No.
Barack Obama is the president. All presidents are over ten feet tall. Therefore, Barack Obama is over ten feet tall.
Valid? Yes.
True Premises? No.
How to Criticize Arguments
IV. Arguments
There are two main ways to criticize an argument:
We'll examine each way of criticizing an argument.
Valid?
Premises true?
Why Soundness is Important
Recall the two ways of criticizing an argument:

1. The argument says things that are not true.
2. The argument says things which do not show that the conclusion is true.
Valid?
Unsound!
Clarification 2
The term "valid" only describes an argument.
"That's a valid point."
Clarifications
A Clarification
Just like with the word "valid," the word "sound" only describes arguments.

It doesn't describe points, or perspectives, or premises.
"That premise is sound."
Premise
Premise
Conclusion
Reading Quizzes
If you do the reading carefully, you should do fine.
If you miss it (or don't want to take it), you can make it up with a Reading Summary.
They're more work than the quiz
You can only do 3 of them
You can either do the Reading Quiz or the Reading Summary for any given day -- not both.
You don't need an excuse (note from Wardenburg, etc.) to do a Reading Summary.
Questions about the Syllabus or Class in General?
What this Class is About
• Does God exist?
• What can we know?
How does scientific progress happen?
• How should I live?
And we want
high standards
for evaluating whether an argument is good or not. So we're beginning with how to evaluate arguments:
Logic
.
1. A fetus is a human being.
2. Abortion ends the life of a fetus.
C. Therefore, abortion violates a fetus's the right to life.
An argument has parts:
The
conclusion
(what argument is supposed to convince you of)
The
premises
(the reasons which are supposed to support the conclusion)
The universe must have had a cause.
The only thing that could have caused the universe is God.
Therefore, God exists.
1.
The things that are said in the argument aren't true.
2.
The things that are said in the argument don't show that the conclusion of the argument is true.
The premises are false, and the conclusion is false. But it's valid because
if
the premises were true, the conclusion would be true, too.
Suppose someone gives you a valid argument for a conclusion that you disagree with.
Question:
Can you logically disagree with the conclusion, but agree with the premises?
No.
So if you agree with the premises, then you
have to
agree to the conclusion! That's the power of validity.
If your argument is sound, then neither of these criticisms work.

Our goal in philosophy (and life!) is to find sound arguments.
Our Procedure for Evaluating Arguments
1. Check for validity.
If not, it's unsound!
If it's valid, go on to step 2.
2. Check each of the premises to see if they're true.
If one (or more) is false, it's unsound.
If they're all true, then it's sound.
Sometimes people say that a point, or point of view, is “valid,” meaning that it is true, plausible, persuasive, should be taken seriously, etc.
This is not what philosophers mean by the term.
Tools for Doing Philosophy
"Some Basic Logical Concepts"
30% - Exams
3 exams, each worth 10%, ~40 minutes long.
A sample Reading Summary is in your syllabus, along with instructions.
John Corvino: "Why Shouldn't Tommy and Jim Have Sex?"
Reading Philosophy
&
Deciding What to Believe

You have the ability to make sense of the readings.

They're short enough that you can read slowly and carefully.
Before You Read
While You Read
The Most Important Lesson
The readings for this class aren't always easy. But they're not so hard you can't understand them.
Having the Right Expectations
Getting Oriented
1. You won’t be able to blow through the reading quickly.
Look for places where you might find the main point of the text:
Some General Advice
When You Get Confused
What Not To Do When You Get Confused
What To Do When You Get Confused
1. Read slowly, carefully, and seriously.


1. Don’t just skim the confusing part and keep going.
1. Pinpoint
the exact place
you stopped understanding and re-read slowly.
2. Look up terms you don’t understand (or think you might not understand).
In a dictionary.
In an encyclopedia of philosophy.
3. Supply your own examples.
4. Take a break! (But not too long!)
5. E-mail me! (And then move on.)
They can be like a puzzle,
but it’s a puzzle you can figure out
.
I'm reading the same texts you are!
It just takes the right strategy, diligence, and practice.
30% of your grade is reading quizzes!
Why Learning to Read Philosophy
Is So Important
40% of your grade is papers -- and to write your papers, you'll need to cite the readings extensively. You can only do that if you do (and understand!) the readings.
Philosophy is difficult. The best way to do well is
repeated exposure
to the ideas.
II. How to Read Philosophy
2. There will be parts of the reading you don't understand right away.
1. The title of the piece.
2. The beginning of the piece.
3. The end of the piece.
The Idea of Finding Implicit Premises
The Term "Implicit Premise"
An Example of an Implicit Premise
Why Finding Implicit Premises is Important
Get into groups of 2-3.
Spend a couple of minutes introducing yourself to the people in your group.
Sometimes an argument is presented to you which is invalid because it is incomplete. In other words, there's a logical gap between the premises and the conclusion that needs to be filled.
We can fill the gap by supplying an
implicit premise
: a premise which is not explicitly in the argument, but which is needed to make the argument valid.
P1.
A fetus is a human being.
Is the argument valid now?
Yes.
C.
Therefore, abortion is wrong.
Our Test:
If there is an important term in the conclusion that's not in any of the premises, then it's probably invalid.
The Test:
If there is an important term in the conclusion that's not in any of the premises, then it's probably invalid.
P2.
Abortion ends a fetus's life.
Implicit
premise
1.
We want to look at arguments in their best possible light -- and that means making them valid.
2.
If an argument does have an implicit premise, that's usually where the problem is.
The Idea of Generating Counterexamples
"Anyone who eats 12,000 calories a day is obese."
"There's never been a movie about destroying jewelry."
IV. How These Skills
Help Us Evaluate Arguments
You could give a general explanation about why you would think this isn't true.
Is this true?
These are all
counterexamples
: specific cases which are supposed to show that a claim is false.
Counterexamples are a specific
kind
of objection. Not all objections are counterexamples!
Practice Finding Implicit Premises
We check for validity
first
because it is often easier to determine validity. (You can know if an argument is invalid even if you doesn't know what the premises mean.)
1.
2.
C.
e.g.:
The universe must have had a cause. The only thing that could have caused the universe is God. So, God exists.
How Validity Works
Imagine you know that two things are true:
1. All Babirusa are Suidae.
2. All Suidae are non-oviparous.
What third thing
do you know?
3. All Babirusa are non-oviparous.
How did you know that, if you don't know what those things mean or whether they're true?
Because you see that if those two things are true, then the third thing must be true. That's validity.
A valid argument:
An invalid argument:
Recap
The Importance of Validity
In other words: since none of the premises said anything about a right to life, how could they show that something about a right to life?
Yes!
Yes!
Yes!
No.
(1st premise
is false.)
Valid?
No.
30% of your grade is exams -- and those are mostly about the readings.
Sound = valid + true premises.
Corvino's article is critiquing arguments that there is something morally wrong with homosexuality.
The point is not to discuss that issue in particular, but to show how he uses the tools we've been developing.
Argument 1
Counterexamples to P2:
Two Things to Notice About All of This
C.
Homosexuality is wrong.
P1.
Homosexuality is unusual or abnormal.
P2.
What is unusual or abnormal is wrong.
"Relatively few people read Sanskrit, pilot ships, play the mandolin, breed goats, or write with both hands, yet none of these activities is immoral simply because it is unusual" (
Corvino, p. 239
)
Valid?
Now it is.
Implicit Premise
Argument 2
Counterexamples to P1:
C.
Homosexuality is wrong.
P1.
Homosexuality is not practiced by other animals.
P2.
What is not practiced by other animals is wrong.
Valid?
Now it is.
Implicit Premise
Homosexuality among animals (sheep, seagulls).
Counterexamples to P2:
"...animals don't cook their food, brush their teeth, participate in religious worship, or attend college; human beings do all of these without moral censure" (
Corvino, p. 239-240
)
2. If an argument has an implied premise, then that's usually where the problem is in the argument.
1. When people make arguments, they often forget to make them valid.
That's why it's important to learn these tools.
Counterexamples
help you criticize premises (explicit or implicit).
Finding implicit premises
helps you see what all of the premises of an argument are (and make clear where a problem is likely to be).
Validity
helps you understand how to find implicit premises.
II. Skill 2: Finding Implicit Premises
An
argument
is a series of statements, where a
conclusion
is supposed to be logically supported by
premises
.
An argument is
valid
, when:
if the premises are true, then the conclusion must be true.
An argument is
sound
when:
(1) it is valid, and
(2) it has only true premises
.

Some Proposed Guidelines for Deciding What to Believe
Proposal 1:
Believe something only when you can be 100% certain of it.
Almost nothing in life is 100% certain, and to go on living we have to have beliefs.
Proposal 2:
Believe something when you have some evidence for it.
Not all evidence is sufficient for basing a belief on it.
A better guideline:
Believe in something when there is significantly more evidence for it than a contrary belief.
Proposal 3:
Believe in something when you have significant evidence for it.
Sometimes there is significant evidence on
both sides
.
Evaluating Arguments with this in Mind
A Good Argument, with Bad Objections
P1.
It is unlikely that there is intelligent life on the moon, unless there are signs of intelligent life there.
P2.
There are no signs of intelligent life on the moon.
C.
Therefore, it is unlikely that there is intelligent life on the moon.
Some bad objections:
There could be intelligent life on the moon even if there are no signs of intelligent life.
(True, but do we have any evidence to believe there
is
intelligent life there?)
Maybe there are signs of intelligent life on the moon and we just can't recognize the signs.
(Maybe, but do we have any evidence to believe there
are
signs?)
What Makes for a Good Objection
Our Guideline for What to Believe:
Believe in something when there is significantly more evidence for it than a contrary belief.
A good objection gives you a reason to not believe an argument.
So a good objection tells you that there is significantly more evidence against a premise than for it.
Maybe there are signs of intelligent life on the moon and we just can't recognize the signs.
(Maybe, but do we have any evidence to believe there are signs?)
That's why this objection is bad:
It's not that the objection is false. It's that saying "maybe x is false" isn't enough for us to decide what to believe. We want to know if there's good evidence that x is false!
The Take-Away Point
It's easy to make
maybe-objections
:
Maybe premise 1 is wrong.
Maybe it's invalid.
But those don't actually help us decide what to believe.
We should aim for
good objections
:
Objections which tell us that
x
is really true.
Objections which tell us that there is good evidence that
x
is true.
Recap: What this Class is About
We're going to talk about really difficult issues:
Does God exist?
What can we know?
How should we live?
II. Deciding What to Believe
Why?
Because we want to know
what we should believe.
Clarification
You can't still make the maybe-objections:
What I
am
saying:
Here's some evidence for why it's invalid.
Here's some evidence for why God isn't the greatest conceivable being.
What I'm
not
saying:
Make maybe-objections as a way of
introducing
a good objection.
(Hint: Your instructors can see this.)
The Syllabus
I. How Lecture Works
II. Recap of the First Day
I will lecture using this presentation software (Prezi).
The lectures are available online. If you go to D2L, there's a link to the Prezis in the original item in the News section.
Accordingly,
don't spend lecture trying to copy down every word
. If you do take notes, take brief notes of what you think is most essential.
We discussed
whether Petitionary Prayer is effective
in order to understand what philosophy is.
Characteristics of philosophy:
It involves
making and

evaluating arguments
for claims.
It involves
analyzing concepts
which are in these claims and arguments.
This means arguments on
multiple sides of an issue
, not just one side.
Empirical observation is relevant
to these arguments and claims, but doesn't decide the answer to a philsoophical question by itself.
Explanation of the policy:
I'm super mean.
Philosophers try to answer these questions by making and evaluating arguments.
Is the problem with this argument that the premises are false?
Is the problem that the conclusion is false?
Clarification:
If an argument passes the test, that doesn't mean it definitely
is
valid.
1.
All mammals breathe air.
2.
All reptiles breathe air.
C.
Therefore, all reptiles are mammals.
A valid argument is an argument where if the premises are true, then the conclusion must be true.
It passes our test, but the conclusion can be false even if the premises are true.
1. If someone is enrolled in this class, then they are a CU student.
2. KR is a CU student.
C. Therefore, KR is enrolled in this class.
Example 4
No.
Valid?
True premises?
No.
Unsound!
1. If you are in Colorado, then you are in Canada.
2. You are in Colorado.
C. Therefore, you are in Canada.
I. Recap
What Philosophy Is
Skills for Doing Philosophy Well
Characteristics of philosophy:
It involves
making and

evaluating arguments
for claims.
It involves
analyzing concepts
which are in these claims and arguments.
This means arguments on
multiple sides of an issue
, not just one side.
Skill 1.
Testing for Validity
Important Concepts
Testing for Validity
Reminders:
How to Test for Validity
Our Test:
If there's an important term in the conclusion that's not in the premises, it's probably invalid.
Skills we'll learn in Unit 1:
Skill 1.
Testing for Validity

Skill 2.
Finding Implicit Premises

Skill 3.
Generating Counterexamples

Skill 4.
Intellectual Empathy

Whether the premises actually are true has nothing to do with validity.
"Valid" and "sound" only apply to arguments -- not premises or conclusions.
P2. Abortion ends a fetus's life.
P1. A fetus is a human being.
C. Therefore, abortion is wrong.
Maybe we could make the argument valid if we inserted a premise. That's what we'll start with today.
P3
. Ending a human being's life is wrong.
A strategy for the worksheet:
1. Find the conclusion first.
2. Then write in the explicit premise.
3. Then figure out what the implicit premise needs to say.
Remember:
Adding in the implicit premise should make the argument valid.
There are lots of ways to object to a claim. One way is to give
a general explanation
for why it is (or is likely) false.
But there's also another way to do it.
But is there an
example
you could give someone to show them it's not true?
III. Skill 3: Generating Counterexamples
Practice Generating Counterexamples
Class Guidelines
These Prezis are online, so you don't need to copy down every word. Spend most of lecture thinking, not writing!
If you have a cellphone or laptop out during class, then I'll ask you to leave for that day.
In your groups, try to come up with counterexamples to the implicit premises in the two arguments you examined.
Discussion (as a class):
What counterexamples did you come up with?
Discussion (as a class):
How did you reconstruct each argument?
A characteristics of a good counterexample:
Most people -- including the people who are putting forward the argument -- would agree that it really is a counterexample.
An
argument
is a series of statements, where a
conclusion
is supposed to be logically supported by
premises
.
An argument is
valid
, when:
An argument is
sound
when:
I. Recap
What Philosophy Is
Skills for Doing Philosophy Well
Characteristics of philosophy:
It involves
making and

evaluating arguments
for claims.
It involves
analyzing concepts
which are in these claims and arguments.
This means arguments on
multiple sides of an issue
, not just one side.
Skill 1.
Testing for Validity
Important Concepts
Testing for Validity
Reminders:
How to Test for Validity
Our Test:

Whether the premises actually are true has nothing to do with validity.
"Valid" and "sound" only apply to arguments -- not premises or conclusions.
P2. An all-powerful being would be able to perform miracles.
P1. God is an all-powerful being.
C. Therefore, miracles are possible.
Skill 2.
Finding Implicit Premises
Skill 3.
Generating
Counterexamples
if the premises are true, then the conclusion must be true.
(1) it is valid, and
(2) it has only true premises
.

If there's an important term in the conclusion that's not in the premises, it's probably invalid.
An Example
An
implicit premise
is a premise which is not explicitly in an argument, but which is needed to make the argument valid.
P1.
A fetus is a human being.
C.
Therefore, abortion is wrong.
P2.
Abortion ends a fetus's life.
Implicit
premise
1.
We want to look at arguments in
their best possible light -- and that
means making them valid.
2.
If an argument does have an implicit premise, that's usually where the problem is.
P3
. Ending a human being's life is wrong.
But in addition to that, there's another kind of objection:
There are lots of ways to object to a claim. One way is to give
a general explanation
for why it is (or is likely) false.
Finding Implicit Premises
Generating Counterexamples
Why finding implicit premises is important:
A
counterexample
is a specific case which is supposed to show that a claim is false.
An example of a claim
: "Anyone who eats 12,000 calories a day is obese."
A counterexample:
Michael Phelps eats 12,000 calories a day, but he isn't obese.
II. Skill #4: Intellectual Empathy
III. Our Procedure for Evaluating Arguments
Checking for Validity
Checking the Truth of the Premises
1.
Check for
validity
using our test: If there's a term in the conclusion that's not in the premises, then it's probably invalid.
2.
If the argument is invalid, we make it valid by supplying an
implicit premise
.
3.
Check each of the premises to see if there are
counterexamples
to them.
4.
Use
intellectual empathy
to see how a person making the argument might respond to objections.
2. Don’t just know
what
is being talked about; know
why
it’s being talked about
3. Don’t assume that just because an author is talking about a view, he or she believes that view.
The Idea of Intellectual Empathy
Practice at Intellectual Empathy
What Intellectual Empathy Is
Clarifications about Intellectual Empathy
Why Intellectual Empathy is Important
Strategies for Becoming Intellectually Empathetic
Intellectual empathy
is the ability to understand the ideas of other people as they do.
Emotional empathy is the ability to understand the feelings someone else has from their point of view.
This doesn’t just mean understanding a view’s conclusions – it also means understanding the
reasons
.
Think of it as understanding an idea from the inside.
1. Understanding doesn’t mean agreeing.
With emotional empathy, you might understand why someone feels the way they do without thinking they are right to feel that way. Likewise, you can understand the reasons without thinking that they’re good reasons.
2. Taking someone’s argument seriously doesn’t mean that all arguments are equally good.
Some arguments aren’t valid. Some arguments have obvious counterexamples. Some arguments have premises which seem implausible.
We want to consider arguments in their best possible light. That means really understanding them the way their proponents understand them.
This course is about learning to evaluate arguments. But you can’t evaluate an argument – judge it to be good or bad – before you understand the argument. 
This is something we’re bad at as a culture!
Question:
Can you think of examples where we judge the other side before we really understand them?
1.
Talk to/read people with whom you disagree.
2.
Try to explain to someone with whom you disagree what their views are before you say why you think they’re wrong!
3.
Try to put yourself in that person’s shoes – imagine how they would argue.
Question:
What can we do to become more intellectually empathetic?
Get into groups of 2-3.
Take a few minutes to introduce yourself to your group members (if you haven't already done so).
Discussion (as a class):
What did groups come up with, starting with the first argument?
So How Do We Decide What to Believe?
When we use intellectual empathy well, we find that even people we disagree with can come up with decent reasons for their beliefs.
So how do we decide what to believe?
A Suggested Test:
We should believe a claim when there's substantially more evidence in favor of it than against it.
A Word on Playing Devil's Advocate
There's a difference between
understanding a view you don't agree with

(Intellectual Empathy)
and
arguing for something you don't agree with (playing Devil's Advocate).
It's great to scrutinize all arguments -- especially the ones where you agree with the conclusion!
But try to follow our guideline:
Believe a claim when there's substantially more evidence in
favor of it than against it.
That will keep us from making silly objections -- ones which
might
be true, but probably aren't.
Also, the readings are very short -- the average reading per day is
under 10 pages long.
2. Don’t give up.
3. Don’t look for the answer on Google or Wikipedia.
III. What Do We Mean by "God"?
Which Concept of "God" Are We Talking About?
The Nature of a Definition
Is a Definition of God Possible?
In this class we're going to consider the concept of God accepted by the major monotheistic religious traditions (Christianity, Judaism, Islam).
The reason is simply that this is the concept of God which most of the arguments in Western philosophy use. There are other concepts of God and other traditions of philosophy, and they're worth studying -- but I haven't been trained in those.
Within the major monotheistic traditions, there is much disagreement about what God is and does.
But there is some agreement about what kind of being God must be.
We want our definition to capture that agreement.
God is by nature mysterious. So is it even possible to come up with a definition of God?
It's possible if we know
anything
about God. And presumably we know
some
things. So as long as we make our definition vague enough, we can still come up with a definition.
Is this God?
No.
Is this God?
Maybe.
Our System for Evaluating Arguments
Checking for Validity
Checking the Truth of the Premises
1.
Check for
validity
using our test: If there's a term in the conclusion that's not in the premises, then it's probably invalid.
2.
If the argument is invalid, we make it valid by supplying an
implicit premise
.
3.
Check each of the premises to see if there are
counterexamples
to them (or other objections).
4.
Use
intellectual empathy
to see how a person making the argument might respond to objections.
An argument is
valid
, when:
An argument is
sound
when:
I. Recap of Unit 1
Skills for Doing Philosophy Well
Skill 1.
Testing for Validity
Important Concepts
Testing for Validity
Reminders:
How to Test for Validity
Our Test:

Whether the premises actually are true has nothing to do with validity.
"Valid" and "sound" only apply to arguments -- not premises or conclusions.
C.
Therefore, the government should lower the drinking age to 18.
P1.
Lowering the drinking age to 18 would allow adults to participate in pleasurable activities.
Skill 2.
Finding Implicit Premises
Skill 3.
Generating
Counterexamples
if the premises are true, then the conclusion must be true.
(1) it is valid, and
(2) it has only true premises
.

If there's an important term in the conclusion that's not in the premises, it's probably invalid.
An Example
An
implicit premise
1.
We want to look at arguments in
their best possible light -- and that
means making them valid.
2.
If an argument does have an implicit premise, that's usually where the problem is.
But in addition to that, there's another kind of objection:
There are lots of ways to object to a claim. One way is to give
a general explanation
for why it is (or is likely) false.
Finding Implicit Premises
Generating Counterexamples
Why finding implicit premises is important:
A
counterexample
Skill 4.
Intellectual Empathy
Intellectual Empathy
Intellectual empathy
Reminders:
1.
Understanding doesn't mean agreeing.
2.
Intellectual Empathy doesn't mean that all arguments are equally good.
Intellectual empathy is important because we want to understand an argument in its best light before we judge it to be bad.
We should use the following
Standard for What to Believe
:
We should believe a claim when there's substantially more evidence in favor of it than against it.
C.
Therefore, the government should lower the drinking age to 18.
P1.
Lowering the drinking age to 18 would allow adults to participate in pleasurable activities.
P2.
The government should allow adults to participate in pleasurable activities.
Implicit premise
An Example
C.
Therefore, the government should lower the drinking age to 18.
P1.
Lowering the drinking age to 18 would allow adults to participate in pleasurable activities.
P2.
The government should allow adults to participate in pleasurable activities.
Counterexamples to P2?
Some adults find it pleasurable to
rob or kill others, but the government shouldn't allow them to do that.
Practice with Intellectual Emapthy
C.
Therefore, the government should lower the drinking age to 18.
P1.
Lowering the drinking age to 18 would allow adults to participate in pleasurable activities
P2.
The government should allow adults to participate in pleasurable activities
Our Counterexample:
Some adults find it pleasurable to, for example, rob or kill others, but the government shouldn't allow them to do that.
Question:
How could we use intellectual empathy to revise the argument and avoid the counterexamples?
that don't harm others.
that don't harm others.
Question:
What's the implicit premise which would make the argument valid?
is a premise which is not explicitly in an argument, but which is needed to make the argument valid.

is a specific case which is supposed to show that a claim is false.
IV. Coming Up with a Definition
A Connecting Thread
Does God have flaws?
This gets us to the definition of God that will be used by St. Anselm:
God is the greatest conceivable being
.
No. We might argue about what is a flaw or not, but we agree that God doesn't have flaws.
Discussion (in groups of 2-3)
How would you define "God"? What qualities do you think God has?
Reminder:
Try to make this consistent with what the major monotheistic religions consider God to be.
Skills
+
What is God?

is the ability to understand the ideas of other people as they do.
Logic and
Critical Thinking
Full transcript