critical thinking 02 truth
DESCRIPTION
Critical Thinking, deductive reasoning, philosophy, truthTRANSCRIPT
A Standard of Critical Thinking
Truth
Review
Principle of Sufficient Principle of Sufficient Reason: for any claim, Reason: for any claim, give reason why it is give reason why it is true, or not.true, or not.
Principle of Charity: for Principle of Charity: for any claim, give it the any claim, give it the strongest possible strongest possible interpretation.interpretation.
Philosophy: the attempt to Philosophy: the attempt to answer, critically, the answer, critically, the epistemological, epistemological, metaphysical, and ethical metaphysical, and ethical questions.questions.
An Issue Question: is a An Issue Question: is a yes-or-no question, and is yes-or-no question, and is the way to formulate the way to formulate questions for the disputed questions for the disputed question method (question method (quaestioquaestio disputatadisputata).).
A virtue is an excellence, A virtue is an excellence, a mean between two a mean between two extremes called vices.extremes called vices.
the question
yes:
no:
Reasons supporting the yes answer or
refuting the no answer.
Reasons supporting the no answer or refuting the yes
answer.
Which side has the better
reasons?
The Disputed Question Method
Review
What is the difference
between the truth, an honest
mistake, and a lie?
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth
The ocean is prettier than the desert &The desert is prettier than the woods.
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth
The desert is prettier than the woods &The woods are prettier than the ocean.
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth Can be indexed to a person, place, time or culture:
According to Alex pizza is better than pot stickers.
>
Does this exhaust all truths?
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth Consider someone who
honestly believes red
means go and green means stop. Is his
belief true, or an honest mistake?
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth
Steering wheels are on the left.
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth
Steering wheels are on the right.
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth Can be indexed to a convention, culture or society:
According to the music business, Tupac is gangsta while My Chemical Romance is emo.
Does this exhaust all truths?
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of TruthConsider a
world without people or
conventions, would water
still boil at the temperature we call 212º Fahrenheit?
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth
The earth is 93 million miles from the sun.—Some think this fact is contingent
—
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth
Water boils at 212º fahrenheit.—Some think this fact is
contingent—it could have been otherwise
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of TruthSuch truths as often expressed ceteris paribus:
The earth is about 93 million miles from the sun on average.Water boils at 212º fahrenheit at standard barometric pressure.
Does this exhaust all truths?
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth
Consider a world with different
natural laws, would
1 + 1 = 2?
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth∏∏ == 3.141592...3.141592...
11 ++ 11 22==
π needs to be exact for a circle to be round
simple arithmetic is the way things are
—Most think these facts are necessary—
they could not have been otherwise
Truth
Matters of Taste or Matters of Taste or OpinionOpinion
Matters of ConventionMatters of Convention
Matters of FactMatters of Fact
Matters of NecessityMatters of Necessity
Four Types of Truth
∏∏ == 3.141592...3.141592...
Truth
to pursue the truth of a claim
avoid matters of taste, fill in the indices, and spell out the ceteris paribus.
Truth is when a claim Truth is when a claim matches what is.matches what is.
Claims are candidates Claims are candidates for truths, such as for truths, such as beliefs stated in beliefs stated in language.language.
The jellyfish has tentacles.
The child looks at the jellyfish.
Drinking milk is healthy.
Same-sex schools are optimal.
Eleven is a prime number.
Jacqui thinks black is more alluring than pink.
The music is loud.Jupiter is bigger than
Mars.
The Constitution of the United States was adopted on September 17, 1787
Romeo and Juliette is a tragedy.
New York is the largest city in the US.
Hockey is better than basketball.
The jellyfish has tentacles.
Why is this true?
Truth
Intensions— the concept that meanings are things with
properties and in relations
Meaning
The jellyfish
Because the thing designated by the
subject has the property expressed by
the predicate.
has tentacles.
How a claim matches what is.
Truth
yes:
no:
Reasons supporting the yes answer or
refuting the no answer.
Reasons supporting the no answer or refuting the yes
answer.
Which side has the better
reasons?
The Disputed Question Method
Does the thing designated by the subject have the property expressed by the predicate?
Applied to Truth
to evaluate the truth of a claim
determine whether the thing designated by the subject has the property expressed by the predicate
The child looks at the jellyfish.
Why is this true?
Truth
The child
The things designated by the nouns stand in the relation expressed
by the predicate.
looks at
the jellyfish.
TruthHow a claim matches
what is.
yes:
no:
Reasons supporting the yes answer or
refuting the no answer.
Reasons supporting the no answer or refuting the yes
answer.
Which side has the better
reasons?
Do the things designated by the nouns stand in the relation expressed by the verb.
Applied to Truth
The Disputed Question Method
to evaluate the truth of a claim
determine whether the things designated by the nouns stand in the relation expressed by the verb.
When a claim matches what is: two forms
subject–Predicate Form subject–Verb–object Form
<<thing> property><<thing> property>
designates/expressesdesignates/expresses
((subject) Predicate)((subject) Predicate)
<<thing> relation<thing>><<thing> relation<thing>>
designates/expresses/designates/expresses/designatesdesignates
Truth
((subject) Verb(object))((subject) Verb(object))
TruthWhen a claim matches what is: subject/Predicate
form
The Claim What is: reality
The sunThe sun’’s gravity well bends light.s gravity well bends light.
<the sun<the sun’’s s gravity well>gravity well>
<<bending bending lightlight>>
<<thing> property><<thing> property>
designates/expressesdesignates/expresses
((The sun’s gravity well) bends light.)
((subject) Predicate)((subject) Predicate)
When a claim matches what is: subject/Verb/object form
The Claim What is: reality
The remora is on the shark.The remora is on the shark.
<remora><remora>
<<sharkshark>>
<<being being onon>> {
Truth
<<thing> relation<thing>><<thing> relation<thing>>
designates/expresses/designates/expresses/designatesdesignates
((The remora) is on (the shark)).((The remora) is on (the shark)).((subject) Verb(object))((subject) Verb(object))
<<thing> property><<thing> property>
designates/expressesdesignates/expresses
((subject) Predicate)((subject) Predicate)
<<thing> relation<thing>><<thing> relation<thing>>
designates/expresses/designates/expresses/designatesdesignates
((subject) Verb(object))((subject) Verb(object))
What is: things with properties and in relations
Meanings as intensions
Meaning
Extension— the concept that meanings are sets and their
members
Meaning
Meanings
MeaningMeanings minus things: concepts (or properties and
relations)
Thing
Concept
+hors
e
Seabiscuit
animal
Equidae
mammal
land animal
fast things
four legged things
_____is four legged.
_____is an animal.
_____is a horse.
_____is faster than_____.
_____is fast.
_____is an Equidae.
_____is bigger than_____.
Concepts
General and Specific
Red is a color.Red is a color.
A color is a wavelength of light.A color is a wavelength of light.
The cherries are red.The cherries are red.
A wavelength of light A wavelength of light is an electromagnetic phenomenon.is an electromagnetic phenomenon.
Concepts
General and Specific
Red is a color.Red is a color.
A color is a wavelength of light.A color is a wavelength of light.
The cherries are red.The cherries are red.
A wavelength of light A wavelength of light is an electromagnetic phenomenon.is an electromagnetic phenomenon.
Red as a concept.
Red as a thing.
Concepts
General and Specific
Red is a color.Red is a color.
A color is a wavelength of light.A color is a wavelength of light.
The cherries are red.The cherries are red.
A wavelength of light A wavelength of light is an electromagnetic phenomenon.is an electromagnetic phenomenon.
Color as a concept.
Color as a thing.
Concepts
Linking the General to the Specific
Red is a color.Red is a color.
A color is a wavelength of light.A color is a wavelength of light.
The cherries are red.The cherries are red.
A wavelength of light A wavelength of light is an electromagnetic phenomenon.is an electromagnetic phenomenon.
more
gen
era
lm
ore
gen
era
l
more
specifi
cm
ore
specifi
c
more
ab
stra
ct
more
ab
stra
ct
more
con
cre
tem
ore
con
cre
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Concepts
Have Extensions
A
BC
D
E
F G
H
I
J
K
LM
NO
PQ
R
S
TU
V
W
X
YY Z
being a vowel
Properties as
Concepts
Concepts
Have Extensions
being divisible by two without a remainder
22
9
11
32 2
7
21
13
66
3
14
144 57
7
Relations as
Concepts
to evaluate the truth of a claim
determine whether the things designated by the nouns are in the extension of the verb.
yes:
no:
Reasons supporting the yes answer or
refuting the no answer.
Reasons supporting the no answer or refuting the yes
answer.
Which side has the better
reasons?
The Disputed Question Method
Are the things designated by the nouns are in the extension of the verb?
45
Definitions
Ambiguity: The Problem of Multiple Meanings
Names can be ambiguous:
Mary
Jupiter
Definitions
Ambiguity: The Problem of Multiple Meanings
Other terms can be ambiguous:
green
fire
Ambiguous applies to Ambiguous applies to terms with more than terms with more than one meaning.one meaning.
Definitions
Vagueness: the Problem of Unclear Extensions
Many terms can be vague:
bald – how many hairs before you stop being bald?
pile – how many make a pile?
A
BC
D
E
F G
H
I
J
K
LM
NO
PQ
R
S
TU
V
W
X
YY Z
being a vowel
is y in the extension of being a
vowel?
Definitions
Vagueness: the Problem of Unclear Extensions
Vague applies to terms Vague applies to terms with unclear extensions.with unclear extensions.
Definitions
Ambiguity and Vagueness
Some Terms Can Be Both Some Terms Can Be Both Ambiguous and Vague—Ambiguous and Vague—Try to come up with some:Try to come up with some:
to define a term
give it one clear meaning
Definitions
Claims with terms as things
Definitions
Claims with terms as things
SubjectSubject PredicatePredicate
‘claim’ means an assertion open to challenge
term meaning
<Thing> <Property>
yes:
no:
Reasons supporting the yes answer or
refuting the no answer.
Reasons supporting the no answer or refuting the yes
answer.
Which side has the better
reasons?
The Disputed Question Method
Do the things in the extension of the term being defined have the property expressed by the meaning?
Definitions
Stipulating definitions
Make up your own terms Make up your own terms that you might characterize that you might characterize as as words that arenwords that aren’’t in the t in the dictionary but should bedictionary but should be..
Definitions
Stipulating definitions
Sniglets*Words that don't appear in the dictionary, but should.
Aeroma (ayr oh' ma) - n. The odor emanating from an exercise room after an aerobics workout.
Aeropalmics (ayr o palm' iks) - n. The study of wind resistance conducted by holding a cupped hand out the car window.
Anaception (an a sep' shun) - n. The body's ability to actually affect television reception by moving about the room.
Animalanche: When you kick your stuffed animals in your sleep and they fall all over you or the floor. (from Kaffit, age 9)
Aquadextrous - adj. Possessing the ability to turn the bathtub faucet on and off with your toes.
Arachnidiot (ar ak ni' di ot) - n. A person, who, having wandered into an "invisible" spider web, begins gyrating and flailing about wildly.
Backspackle (bak' spak uhl) - n. Markings on the back of one's shirt from riding a fenderless bicycle.
Baldage (bald' aj) - n. The accumulation of hair in the drain after showering.
Bevemeter - The distance a coaster will stick to the bottom of a wet glass before falling to the table.
Bimp (bimp) - n. A blurry or "double-edged" felt-tip marker
Bixplex (biks' pleks) - n. Psychological block in which a person cannot choose which color of disposable lighter to purchase.
Definitions
Stipulating definitions
Sniglets show that we may prescribe or stipulate a definition for how a term ought to be used.
The examples from the dictionary show that we may describe or designate a definition for how a term is actually used.
In this class we will prescribe or stipulate technical definitions for how terms ought to be used.
Normative definitions Normative definitions which prescribe or which prescribe or stipulate how a term stipulate how a term ought to be used.ought to be used.
Normative claims which Normative claims which prescribe or stipulate prescribe or stipulate how things ought to be.how things ought to be.
Descriptive definitions Descriptive definitions which describe or which describe or designate how a term is designate how a term is actually used.actually used.
Descriptive claims which Descriptive claims which describe or designate describe or designate how things actually are.how things actually are.
Law of Assumption—Law of Assumption—assume anything at any assume anything at any time.time.
Law of Assumption—Law of Assumption—assume anything at any assume anything at any time.time.
Sniglets are an example of applying this law.
Law of Assumption—Law of Assumption—assume anything at any assume anything at any time.time.
Thought experiments are based on assumptions.
Law of Assumption—Law of Assumption—assume anything at any assume anything at any time.time.
Critical Thinking has techniques to reject faulty assumptions.
define key terms
key terms are terms needed for the claim to be evaluated as true or false,
they are terms whose properties or relations need
to be specified or whose extensions need to be
clarified.
define technical terms
technical terms are terms needed for critical thinking, such as truth, charity, and
reason.
The Standard of Truth—The Standard of Truth—accept only those claims accept only those claims and definitions that have and definitions that have the best reasons for being the best reasons for being true. true.
ConsistencyConsistency
Assignment
How do you define contradictions?
Read the cases and list the contradictions you
find.
How do you tell when a conjunction is false?