Strengthening
Critical Thinking Skills
by Elizabeth A. Johnson
College Board Consultant
How do these
three ideas fit
together?
Everyone has a right to an opinion.
Some opinions are better than others.
Some opinions are wrong.
What is a fact?


A fact is a statement
that can be verified
by an independent
observer.
A fact cannot be
shown to be false.
Inference and assertion


An inference is a statement about the
unknown that is based on known facts.
An assertion is a statement about the
unknown. Supported by evidence, it is less
certain than a fact.
Fact, inference, assertion
Degree of
Uncertainty
Assertion
Inference
Fact
Comparing degrees of certainty

The certainty of a fact
may be cast in doubt
if new information
appears.



Inference?
Assertions give
meaning to facts.
Does the table
represent a true fact?
100
90
80
70
60
50
40
30
20
10
0
Fact
Inference
Assertion
Dichotomies



A dichotomy is a statement offering two
mutually exclusive alternatives.
It takes the form A v ~A, where v means or
Is gender a true dichotomy?
Literal vs. Figurative Truth


A fact is literally true: 1 + 1 = 2
Proverbs are examples of figurative truth:




“Slow and steady wins the race.”
“He who hesitates is lost.”
“Power corrupts; absolute power corrupts
absolutely.”
An assertion is half as true as a fact.
Varieties of Truth




Scientific, empirical truth
Social sciences (Psychology, Sociology,
Economics)
Historical truth: Power corrupts.
Literary truth: A theme of a novel


“Be true! Be true!” – The Scarlet Letter
Religious/Philosophical truth: “An eye for an eye
only makes the whole world blind.”
-- Gandhi
Qualities of Truth
Science
Social Sciences
Humanities
May vary according to
time, place
May vary according
to time, place
Finds answers to
answerable
questions
Finds answers to
answerable questions
Offers answers to
unanswerable
questions
Replicable
May be replicable
Truth of human
experience.
Math, logic, physics,
chemistry, biology
Psychology, sociology,
Anthropology, econ.
History, philosophy,
literature, religion
Av~A
A v ~ A is ideal
A^~A
Universal
Answerable vs. ‘Unanswerable’
Questions





What day is today?
Where were you
born?
What is the capital of
France?
Can Mars sustain life?
Are electrons
particles or waves, or
both?





Should the Celtics
hire a new coach?
Is democracy the best
form of government?
Why do good people
suffer?
Who am I?
Why are we here?
Two Types of Opinions

Personal opinions are

neither true nor
false
unique to each
individual
All equally valid





Personal opinions
reflect one’s taste.
A reasoned opinion
may be supported by
facts, reasons, and
other evidence.
Are all equally valid?
Personal vs. Reasoned
Opinions




“The Beatles are the best
rock group ever!”
Face jewelry is stylish.
JFK was a great
president.
“I know what I like, and I
don’t like Picasso.”




The earth was formed 4
billion years ago.
Humans are the only
tool-making animal.
The Civil War was caused
by Northern industrial
expansion.
Shakespeare is the
greatest writer who ever
lived.
Aesthetics
Classical philosophy considers three main questions:



What is Truth?
What is Justice?
What is Beauty?
Epistemology
Politics
Aesthetics
Aesthetics asserts the existence of objective knowledge
regarding the nature of beauty.
Modern aesthetics tends to blend truth and beauty
Uneducated vs. Educated
Opinion



A: “The Celtics should
hire a new coach.”
Segregated schools
preserve the natural
order of society.
A: “Sonic Youth music
sounds like a rusty
washing machine.”



B: “The Celtics should
hire a new coach.”
Gilligan’s research
supports the value of
single-sex education.
B: “Sonic Youth is an
original, seminal band.”
Educated opinions




Rebecca Nurse was a witch.
Disease is caused by mal-aria (‘bad air’) or
demons.
Humans and chimps are nearly identical, owing
to similar genetics.
The education of women is the key to solving
most social and economic problems of the poor.
How do these
three ideas fit
together?
Everyone has a right to an opinion.
Some opinions are better than
others.
Some opinions are wrong.