Critical Thinking Lecture Notes

By
Girma Ayalew
Department of Philosophy

©2020
 CHAPTER ONE
1. Meaning and Nature of Philosophy
It is difficult to define philosophy in terms of a specific subject
matter. However, we can define it etymologically or literal and
conceptual.
1. Etymological Definition
 Philosophy comes from two Greek words: ―philo and ―sophia,
which mean ―love and ―wisdom as love of wisdom.
 The ancient Greek thinker Pythagoras was the first to use the word
―philosopher to call a person who clearly shows a marked
curiosity/interest in the things he experiences.
 Based on the Socratic understanding of wisdom, philosophy, as
 a pursuit of wisdom thus,
 the development of critical habits,
 the continuous search for truth, and
 Con’d….
2. Conceptual definition of philosophy
 It is a rational and critical enterprise that tries to formulate and
answer fundamental questions through an intensive application of
reason- an application that draws on analysis, comparison, and
evaluation.
 It involves reason, rational criticism, examination, and analysis.
 It attempts to formulate rationally defensible answers to certain
fundamental questions concerning the nature of reality, the nature of
value, and the nature of knowledge and truth-constructive side.
 It deals with giving a rational critic, analysis, clarification, and
evaluation of answers given to basic metaphysical, epistemological,
and axiological questions-critical side.
 It is an activity. It is not something that can be easily mastered or
learned in schools.
 However, what makes someone a great philosopher is not the
produced philosophy, but his/her outstanding ability to philosophize.
 Con’d….
Basic Features of Philosophy
As an academic discipline, philosophy has its own salient
features that distinguishes it from other academic disciplines,
be it natural, social and humanistic disciplines.
 Questioning/criticism is not the final end of philosophy,
though raising the right question is often taken not only as the
beginning and direction of philosophy but also as its essence.
The general features of philosophy;
1) Philosophy is a set of views or beliefs about life and the
universe, which are often held uncritically.
We refer to this meaning as the informal sense of philosophy or
―having a philosophy. Usually when a person says ―my
philosophy is, he/she is referring to an informal personal
attitude to whatever topic is being discussed.
 Con’d….
2) Philosophy is a process of reflecting on and criticizing our
most deeply held conceptions and beliefs.
 This is the formal sense of ―doing philosophy. These two
senses of philosophy-having and ―doing- cannot be treated
entirely independent of each other, if we did not have a
philosophy in the formal, personal sense, then we could not do
a philosophy in the critical, reflective sense. However, having a
philosophy is not sufficient for doing philosophy.
 A genuine philosophical attitude is searching and critical; it is
open-minded and tolerant- willing to look at all sides of an
issue without prejudice.
 To philosophize is not merely to read and know philosophy;
there are skills of argumentation to be mastered, techniques of
analysis to be employed, and a body of material to be
appropriated such that we become able to think philosophically.
 Con’d….
3) Philosophy is a rational attempt to look at the world as a
whole.
Philosophy seeks to combine the conclusions of the
various sciences and human experience into some
kind of consistent worldview. Philosophers wish to
see life, not with the specialized slant of the scientist
or the businessperson or the artist, but with the overall
view of someone cognizant of life as a totality.
Philosophy, attempts to bring the results of human
inquiry, religious, historical, and scientific into some
meaningful interpretation that provides knowledge
and insight for our lives.
 Con’d….
4)Philosophy is the logical analysis of
language and the clarification of the
meaning of words and concepts.
It is one function of philosophy. In
fact, nearly all philosophers have used
methods of analysis and have sought to
clarify the meaning of terms and the
use of language.
 Con’d….

5) Philosophy is a group of perennial problems that

interest people and for which philosophers always
have sought answers.
Philosophy presses its inquiry into the deepest
problems of human existence. Some of the
philosophical questions raised in the past have been
answered in a manner satisfactory to the majority of
philosophers.
 Many questions, however, have been answered
only tentatively, and many problems remain
unsolved. The followings are some philosophical
questions.
 Con’d….

• What is truth?
• What is the distinction between right and wrong?
• What is life and why am I here?
• Why is there anything at all?
• What is the place of life in this great universe?
• Is the universe friendly or unfriendly?
• Do things operate by chance or through sheer
mechanism, or is there some plan, purpose, or
intelligence at the heart of things?
• Is my life controlled by outside forces, or do I
have a determining or even a partial degree of
control?
 Con’d….
• Why do people struggle and strive for their rights, for justice, for
better things in the future?
• What do concepts like ―right‖ and ―justice‖ means, and what are
the marks of a good society? Often men and women have been
asked to sacrifice their lives, if need be, for certain values and
ideals.
• What are the genuine values of life and how can it attained?
• Is there really a fundamental distinction between right and wrong,
or is it just a matter of one‘s own opinions?
• What is beauty?
• Should religion count in a person‘s life?
• Is it intellectually valid to believe in God?
• Is there a possibility of a ―life after death?
• Is there any way we can get an answer to these and many related
questions?
• Where does knowledge come from, and can we have any
 Con’d….

• Philosophy also means the various theories or

systems of thought developed by the great
philosophers, such as
• Socrates, Plato, Aristotle, Augustine, Aquinas,
Descartes, Spinoza, Locke, Berkeley, Kant,
Hegel, Nietzsche, Royce, James, Dewey,
Whitehead, and others.
Without these people and their thoughts,
 philosophy would not have the rich content it has
today. Even though we may be unconscious of the
fact, we are constantly influenced by ideas that
have come down to us in the traditions of society.
 Con’d….
Core Fields of Philosophy
The followings are the core fields of philosophy.
A. Metaphysics,
B. Epistemology,
C. Axiology, and
D. Logic
A. Metaphysics:
The term metaphysics is derived from the Greek words
“meta” means (―beyond ―upon or ―after) and physika,
means (―physics). Literally, it refers
“those things after the physics.”
‘Aristotle‘s writings on ‗first philosophy‘ came after his treatise on
physics, therefore,
Aristotle‘s editor, Andronicus of Rhodes, named them metaphysics.
 Con’d….

Metaphysics is the branch of philosophy that studies

about the ultimate nature of reality or existence.
It deals with issues of
 reality,
 God,
 freedom,
 soul/immortality,
 the mind-body problem,
 form and substance relationship,
 cause and effect relationship, and other related issues.
 Metaphysicians seek an irreducible/absolute foundation of
reality from which absolute knowledge or truth can be
induced/encouraged and deduced/reasoned.
 Con’d….

Here are some of the questions that Metaphysics primarily deals with:
 What is reality?
 What is the ultimately real?
 What is the nature of the ultimate reality?
 Is it one thing or is it many different things?
 Can reality be grasped by the senses, or it is transcendent?
 What makes reality different from a mere appearance?
 What is mind, and what is its relation to the body?
 Is there a cause and effect relationship between reality and
appearance?
 Does God exist, and if so, can we prove it?
 Are human actions free, or predetermined by a supernatural force?
 What is human being? A thinking mind? A perishable body? Or a
combination of both?
 What is time?
 Con’d….
Metaphysical questions may be divided into four
subsets or aspects.
i) Cosmological Aspect: it study about the origin, nature, and
development of the universe as an orderly system. Questions such
as these populate the realm of cosmology are:
 How did the universe originate and develop?
 Did it come about by accident or design?
 Does its existence have any purpose?
ii) Theological Aspect: it is part of religious theory that deals with
conceptions of and about God.
 Is there a God? If so, is there one or more than one?
 What are the attributes of God?
 If God is both all good and all powerful, why does evil exist?
 If God exists, what is His relationship to human beings and the
 Con’d….

iii) Anthropological Aspect: It deals with the study of

human beings and asks questions like the following:
 What is the relation between mind and body?
 Is mind more fundamental than body, with body
depending on mind, or vice versa?
 What is humanity‘s moral status?
 Are people born good, evil, or morally neutral?
 To what extent are individuals free?
 Do they have free will, or are their thoughts and
actions determined by their environment,
inheritance, or a divine being?
 Does each person have a soul? If so, what is it?
 Con’d….

iv) Ontological Aspect: Ontology is the study of the nature

of existence, or what it means for anything to exist.
Several questions are central to ontology:
 Is basic reality found in matter or physical energy (the
world we can sense), or is it found in spirit or spiritual
energy?
 Is it composed of one element (e.g., matter or spirit), or
two (e.g., matter and spirit), or many?
 Is reality orderly and lawful in itself, or is it merely
orderable by the human mind?
 Is it fixed and stable, or is change its central feature?
 Is this reality friendly, unfriendly, or neutral toward
humanity?
 Con’d….

B. Epistemology:
Etymologically, the word epistemology has been
derived from the Greek words episteme, meaning
knowledge, understanding, and logos-study of.
It studies about the nature, scope, meaning, and
possibility of knowledge.
It deals with issues of knowledge, opinion, truth,
falsity, reason, experience, and faith.
 Epistemology is also referred to as theory of
knowledge.
 Con’d….

• It seeks to answer the basic questions as:

o What is true?
o How do we know? Thus, epistemology covers two areas: the
content of thought and thought itself.
o The study of epistemology deals with issues related to the
dependability of knowledge and the validity of the sources
through which we gain information.
• The following are among the questions/issues with which
Epistemology deals:
 What is knowledge?
 What does it mean to know?
 What is the source of knowledge? Experience? Reason? Or both?
 How can we be sure that what we perceive through our senses is
correct?
 Con’d….

What makes knowledge different from belief or

opinion?
 What is truth, and how can we know a statement
is true?
Can reason really help us to know phenomenal
things without being informed by sense
experiences?
 Can our sense experience really help us to know
things beyond our perception without the
assistance of our reasoning ability?
What is the relationship and difference between
faith and reason?
 Con’d….

• Epistemology seeks answers to a number of

fundamental issues.
i. reality can even be known.
• Skepticism: in its narrow sense is the position
claiming that people cannot acquire reliable
knowledge and that any search for truth is in
ineffective(vain).
• A term closely related to skepticism is
agnosticism. Agnosticism is a profession of
ignorance in reference to the existence or
nonexistence of God.
 Con’d….

ii. all truth is relative, or whether some truths are

absolute. Is all truth subject to change? Is it
possible that what is true today may be false
tomorrow? If the answer is Yes to the previous
questions, such truths are relative. If, however,
there is Absolute Truth, such Truth is eternally
and universally true irrespective of time or place.
Closely related to the issue of the relativity and
absoluteness of truth are the questions of whether
knowledge is subjective or objective, and
whether there is truth that is independent of
human experience.
 Con’d….
Sources of human knowledge
a. Empiricism
• Central to most people‘s answer to that question
related to knowledge obtained through the senses.
Empirical knowledge appears to be built into the
very nature of human experience.
• i.e Knowledge that can be gained from human
experience is called empiricism. The questions are:
If one accepts the fact that there is truth and even
Truth in the universe, how can human beings
comprehend such truths? How do they become
human knowledge?
 Cont’d…

b. Rationalism (reason): The view that reasoning,

thought, or logic is the central factor in knowledge is
known as rationalism. The rationalist, in emphasizing
humanity‘s power of thought and the mind‘s
contributions to knowledge, is likely to claim that the
senses alone cannot provide universal, valid judgments
that are consistent with one another.
Rationalism in a less extreme form claims that people
have the power to know with certainty various truths
about the universe that the senses alone cannot give. In
its extreme form, rationalism claims that humans are
capable of arriving at irrefutable knowledge
independently of sensory experience.
 Con’d….
Formal logic is a tool used by rationalists.
c. intuition: expressions as immediate feeling of
certainty.
Intuition occurs beneath the threshold of
consciousness and is often experienced as a sudden
flash of insight.
Intuition has been claimed under varying
circumstances as a source of both religious and
secular knowledge. Certainly many scientific
breakthroughs have been initiated by intuitive
hunches that were confirmed by experimentation.
 Con’d….

d. revelation: Revealed knowledge has been of prime

importance in the field of religion.
It presupposes a transcendent supernatural reality that
breaks into the natural order. Christians believe that
such revelation is God‘s communication concerning
the divine will. Believers in supernatural revelation
hold that this form of knowledge has the distinct
advantage of being an omniscient source of
information that is not available through other
epistemological methods. The truth revealed
through this source is believed by Christians to be
absolute and uncontaminated
 Con’d….
e. Authority: knowledge is accepted as true because it comes from
experts or has been sanctified over time as tradition. In the
classroom, the most common source of information is some
authority, such as a textbook, teacher, or reference work.
C. Axiology: is the study or theory of value. The term Axiology stems
from two Greek words- ―Axios, meaning ―value, worth, and
―logos, meaning ―reason/ theory/ symbol / science/study of.
Hence, Axiology is the philosophical study of value, which originally
meant the worth of something. Axiology asks the philosophical
questions of values that deal with notions of what a person or a
society regards as good or preferable, such as:
 What is a value?
 Where do values come from?
 How do we justify our values?
 How do we know what is valuable?
 Con’d….

 What kinds of values exist?

 Can it be demonstrated that one value is better than
another?
 Who benefits from values?
 Etc
Axiology deals with the above and related issues of
value in three areas, namely;
Areas of Axiology
I. Ethics,
II. Aesthetics, and
III. Social/Political Philosophy.
 Con’d….

I. Ethics: which is also known as Moral Philosophy.

 It is a science that deals with the philosophical study of
moral principles, values, codes, and rules, which may be
used as standards for determining what kind of human
conduct/action is said to be good or bad, right or wrong.
 Ethics raises various questions including:
 What is good/bad?  What is right/wrong?
 Is it the Right Principle or the Good End that makes
human action/conduct moral?
 Is an action right because of its good end, or it is good
because of its right principle?
 Are moral principles universal, objective, and
unconditional, or relative, subjective and conditional?
 Con’d….

 What is the ultimate foundation of moral principles?

The supernatural God? Human reason? Mutual social
contract? Social custom?
 Does God exist? If so, is He Benevolent and
Omnipotent?
 If God is Benevolent, why He creates evil things? If
God does not create evil things, then, there must be
another creator who is responsible to creation of the evil
things? But, if it is so, how can God be an Omnipotent
creator?
 Why we honor and obey moral rules? For the sake of
our own individual benefits?, or for the sake of others?,
or just for the sake of fulfilling our infallible duty?
 Con’d….

• Ethics, or ethical studies, can be grouped into three

broad categories:
1. Normative ethics,
2. Meta-ethics, and
3. Applied Ethics.
1. Normative Ethics: refers to the ethical studies that
attempt to study and determine precisely the moral rules,
principles, standards and goals by which human beings
might evaluate and judge the moral values of their
conducts, actions and decisions. It is the reasoned search
for principles of human conduct, including a critical
study of the major theories about which things are good,
which acts are right, and which acts are blameworthy.
 Con’d….

• Consequentialism or Teleological Ethics,

• Deontological Ethics, and
• Virtue Ethics are the major examples of normative ethics.
2. Meta-ethics: is the highly technical philosophical discipline
that deals with investigation of the meaning of ethical terms,
including a critical study of how ethical statements can be
verified. It is more concerned with the meanings of such ethical
terms as good or bad and right or wrong than with what we
think is good or bad and right or wrong.
 Moral Intuitionism,
 Moral Emotivism,
 Moral Prescriptivism,
 Moral Nihilism, and
 Ethical Relativism are the main examples of meta-ethical
 Con’d….

3. Applied Ethics: is a normative ethics that attempts

to explain, justify, apply moral rules, principles,
standards, and positions to specific moral problems,
such as capital punishment, euthanasia, abortion,
adultery, animal right, and so on.
II. Aesthetics: is the theory of beauty. It studies about
the particular value of our artistic and aesthetic
experiences. It deals with beauty, art, enjoyment,
sensory/emotional values, perception, and matters of
taste and sentiment.
 Con’d….
• The following are typical Aesthetical questions:
 What is art?
 What is beauty?
 What is the relation between art and beauty?
 What is the connection between art, beauty, and truth?
 Can there be any objective standard by which we may judge
the beauty of artistic works, or beauty is subjective?
 What is artistic creativity and how does it differ from
scientific creativity?
 Why works of art are valuable?
 Can artistic works communicate? If so, what do they
communicate?
 Does art have any moral value, and obligations or constraints?
 Con’d….

III. Social/Political Philosophy: studies about of the value

judgments operating in a civil society, be it social or political.
The following questions are some of the major Social/Political
Philosophy primarily deal with:
 What form of government is best?
 What economic system is best?
 What is justice/injustice?
 What makes an action/judgment just/unjust?  What is
society?
 Does society exist? If it does, how does it come to existence?
 How are civil society and government come to exist?
 Are we obligated to obey all laws of the State?
 What is the purpose of government?
 Importance of Learning Philosophy

There are many characteristics of self-actualization to

whose achievement studying philosophy has a
primordial contribution. Here below are some of
them.
1) Intellectual and Behavioral Independence:- This is
the ability to develop one‘s own opinion and belief.
2) Reflective Self-Awareness:- Philosophy helps us to
intensify our self-awareness by inviting us to
critically examine the essential intellectual grounds of
our lives.
3) Flexibility, Tolerance, and Open-Mindedness:-
evolutionary nature of intellectual achievement and
 Con’d….

4) Creative and Critical Thinking: - this is the ability

to develop original philosophical perspective on
issues, problems, and events; and to engage them
on a deeper level.
5). Conceptualized and well-thought-out value
systems in morality, art, politics, and the like: -
since philosophy directly deals with morality, art,
politics, and other related value theories, studying
philosophy provides us with an opportunity to
formulate feasible evaluations of value; and
thereby to find meaning in our lives.
 CHAPTER TWO
THE CONCEPT OF LOGIC
The word logic comes from Greek word logos, which
means sentence, discourse, reason, truth and rule.
Logic in its broader meaning is the science, which
evaluates arguments and the study of correct
reasoning.
It could be also defined as the study of methods and
principles of correct reasoning or the art of correct
reasoning.
• is a branch of philosophy that deals with arguments
• is the science that evaluates arguments
• aims at criticizing the arguments of others and constructing arguments
of our own.
 Con’d….

Logic can be defined in different ways. Here below are some

definitions of logic:
 Logic is a science that study about methods for evaluating
arguments whether the premises of arguments adequately support
or provide a good evidence for the conclusions.
 Logic is a science that helps to develop the method and principles
that we may use as a criterion for evaluating the arguments of
others and as a guide to construct good arguments of our own.
 Logic is the attempt to codify the rules of rational thought.
Logicians explore the structure of arguments that preserve truth or
allow the optimal extraction of knowledge from evidence.
 Logic is one of the primary tools of philosophers use in their
inquiries. The precision of logic helps them to cope with the
subtlety of philosophical problems and the often misleading nature
of conversational language.
 Con’d….

What are the Benefit of Studying Logic?

‘Logic sharpens and refines our natural gifts to think,
reason and argue.’’ (C. S. Layman).
 We use logic in our day-to-day communications. As
human beings, we all think, reason and argue; and
we all are subject to the reasoning of other people.
Some of us may think well, reason well and argue
well, but some of us may not.
 The ability to think, reason and argue well might
partially be a matter of natural gift.
 Cont’d….
The major benefits that we can gain from the study of logic
are:
a) develop the skill needed to construct sound (good) and
fallacy-free arguments of one‘s own and to evaluate the
arguments of others;
b) provides a fundamental defense against the prejudiced
and uncivilized attitudes that threaten the foundation of
a civilized and democratic society;
c) distinguish good arguments from bad arguments;
d) understand and identify the common logical errors in
reasoning;
e) understand and identify the common confusions that
often happen due to misuse of language;
 Cont’d….
g) disclose ill-conceived policies in the political sphere, to
be careful of disguises, and to distinguish the rational from
irrational and the sane from the insane.
h) increase our confidence when we criticize the arguments
of others and when we advance arguments of our own.
The goals of logic is to
 produce individuals who are critical, rational
and reasonable both in the sphere of public and
private life.
Systematically and carefully understand the basic
concepts of the subject and be able to apply them
in the actual situations.
 What is an Argument?
 arguments in our day-to-day experience.
 it is a group of statements, one or more of
which (the premise) are claimed to provide
support for, or reason to believe, one of the
other, the (conclusion).
the term argument has a very specific meaning
in logic. It does not mean, for example, a mere
verbal fight, as one might have with one‘s
parent, spouse, or friend.
 Features of an argument
1. A group of statements. That is, the first
requirement for a passage to be qualified as an
argument is to combine two or more statements.
Statement is a declarative sentence that has a truth-value
of either true or false. That is, statement is a sentence that
has truth-value. Hence, truth and falsity are the two
possible truth-values of a statement.
Example:
a) Dr. Abiy Ahmed the current Prime Minister of Ethiopia.
b) Mekelle is the capital city of Tigray Region.
c) Ethiopia was colonized by Germany. These are
statements. Statement a and b are true statements, but c is
false statement.
 Cont’d…..

N.B: Logicians used proposition and

statement interchangeably.
However, in strict (technical) sense,
Proposition is the meaning or
information/ content of a statement.
The term statement is used to refer
both premises and a conclusion.
 Cont’d…..
However, there are sentences that are not statements,
and hence should be used to construct an argument.
Examples:
a) Would you close the window? (Question)
b) Let us study together. (Proposal)
c) Right on! (Exclamation)
d) I suggest that you read philosophy texts.
(Suggestion)
e) Give me your ID Card, Now! (Command)
In fact, sentence is a group of words or
phrases that enables us to:
 express ideas or thought meaningfully.
 sentences cannot be either true or
false. none of them can be classified as
statement.
 none of them can make up an
argument.
No premises and conclusion.
2. The statements that make up an argument are
divided into premise(s) and conclusion.
 A passage contains two or more statements
cannot guarantee the existence of an
argument.
An argument is a group of statements, which
contains at least one premise and one and
only one conclusion. It clear that an argument
may contain more than one premise but only
one conclusion
Argument always attempts to justify a claim.
• A premise is a statement that set forth the
reason or evidence, which is given for
accepting the conclusion of an argument. It
is claimed evidence; and
• A conclusion is a statement, which is
claimed to follow from the given evidence
(premise). In other words, the conclusion is
the claim that an argument is trying to
 Cont’d….
Example 1 Example 2
1) All Ethiopians are 2) Some Africans are
Africans.(Premise 1) black. (Premise-1)
Tsionawit is an Zelalem is an African.
Ethiopian. (Premise 2) (Premise-2)
Therefore, Tsionawit Therefore, Zelalem is
is an African. black. (Conclusion)
(Conclusion)
 Cont’d….

• In both arguments, the first two

statements are premises, because
they are claimed to provide
evidence for the third statement,
whereas the third statement is a
conclusion because it is claimed to
follow from the given evidences.
 Cont’d…..
• In the first argument, the premises really do
support the conclusion, they give good
reason for believing that the conclusion is
true, and therefore, the argument is a good
one.
• But the premises of the second argument
fail to support the conclusion adequately.
Even if they may be true, they do not
provide good reason to believe that the
conclusion is true. Therefore, it is bad
 Technique to identify premises from a conclusion and vice versa

Arguments contain certain indicator words that provide clues in identifying premises and
conclusion. Here below are some Conclusion Indicators:
 Therefore
 Wherefore
 Accordingly
 Provided that
 It must be that
 We may conclude
 Entails that
 Hence
 It shows that
 Whence
Thus
Consequently
We may infer
It implies that
As a result
So
 Cont’d……
Here below are some typical Premise Indicators:
Since
As indicated by
Because
Owing to
Seeing that
Given that
As For
In that
May be inferred from
Inasmuch as

 Cont’d………
Example; You should avoid any form of cheating on exams
because cheating on exams is punishable by the Senate
Legislation of the University.
for this reason
can be both premise and conclusion indicator. The statement
that comes before “for this reason” is the premise of an
argument and the statement that comes after for this reason
is the conclusion.
Eg: Tsionawit is a faithful wife, for Ethiopian women are faithful
wives and Tsionawit is an Ethiopian.
The premise indicator for‘‘ goes with both Ethiopian
women are faithful wives‘‘ and Tsionawit is an Ethiopian”.
These are the premises. Tsionawit is a faithful wife is the
conclusion
 Techniques of Recognizing Arguments
Recognizing Argumentative Passages
Two conditions must be fulfilled for a passage
to purport to prove something:
1) At least one of the statements must claim to
present evidence or reasons.
2) The alleged evidence or reasons supports or
implies something (something follows from the
alleged evidence).
 Cont’d…..
A passage which purport to prove something is only the one that
fulfils the following two claims:
1. Factual Claim: at least one of the statements must claim to
present evidence or reasons. (This mainly refers premises) Deciding
whether it is fulfilled often falls outside the domain of logic.
2. Inferential Claim: there must be a claim that something follows
from the alleged evidence. (This mainly refers the logical
relationship between premises and the conclusion). something
follows from something.
The inferential claim may be explicit or implicit.
 I. Explicit inferential claim
• Is usually stated by premise or
conclusion indicator words (thus,
since, because, hence, therefore, and
so on).
• It shows the relationship between the
premises and the conclusions.
• Example: Gamachuu is my biological
father, because my mother told so.
 Cont’d….
• In this example, the premise indicator word
expresses the claim that evidence supports
something, or that evidence is provided to
prove something. Hence, the passage is an
argument.
II. An implicit inferential claim:
there is an inferential relationship between the
statements in a passage,
 But, the passage contains no indicator words.
 Cont’d….
• Example: Since Edison invented the
phonograph, there have been many
technological developments. Since Edison
invented the phonograph, he deserves credit
for a major technological development.
• In the first passage the word ‗‗since‘‘ is used
in a temporal sense. It means from the time
that.‘‘ Thus, the first passage is not an
argument. In the second passage since is used
in a logical sense, and so the passage is an
argument
 Cont’d….
• As a result, not everyone will agree about
every passage. Sometimes the only
answer possible is a conditional one:
• ―If this passage contains an argument,
then these are the premises and that is the
conclusion.
• Shortly, not every passage is an argument.
 Recognizing Non-argumentative Passages
Non-argumentative passages are passages,
which lack an inferential claim. These include
a. simple non-inferential passages, expository
passages,
b. illustrations,
c. explanations, and
d. conditional statements.
Passages that lack an inferential claim may be
statements, which could be premises,
conclusion, or both.
 a. Simple Non-inferential Passages
 are unproblematic passages that lack a claim that
anything is being proved. Such passages contain
statements that could be premises or conclusions
(or both), but what is missing is a claim that any
potential premise supports a conclusion or that any
potential conclusion is supported by premises.
Passages of this sort include
warnings,
pieces of advice,
 statements of belief or opinion,
loosely associated statements, and
 reports.
 i. Warning
It is a form of expression that is intended
to put someone on guard against a
dangerous or detrimental situation.
Example: Whatever you promise to tell,
never confide political secrets to your
wife. In this passage, no evidence is
given to prove that the statement is true;
and if no evidence is given to prove that
the statement is true, then there is no
argument.
 ii. A piece of advice
• is a form of expression that makes a
recommendation about some future decision or
course of conduct.
Example: After class hours, I would suggest that
you give careful consideration to the subject
matter you have discussed.
As with warnings, there is no evidence that is
intended to prove anything in piece of advices,
and hence there is no argument in the above
passage.
 iii. A statement of belief or opinion
• is an expression about what someone happens
to believe or think about something.
Example: We believe that our university must
develop and produce outstanding students who
will perform with great skill and fulfill the
demands of our nation. This passage does not
make any claim that the belief or opinion is
supported by evidence, or that it supports some
conclusion, and hence does not contain an
argument.
 iv. Loosely associated statements
• may be about the same general subject, but
they lack a claim that one of them is proved by
the others.
• Example: Not to honor men of worth will keep
the people from contention; not to value goods
that are hard to come by will keep them from
theft; not to display what is desirable will keep
them from being unsettled of mind.
• Because there is no claim that any of these
statements provides evidence or reasons for
believing another, there is no argument.
 v. Report
consists of a group of statements that convey
information about some topic or event.
Example: The great renaissance dam of Ethiopia
has opened an employment opportunity for
thousands of Ethiopians. In its completion,
thirteen thousand Ethiopians are expected to be
hired. These statements could serve as the
premises of an argument, but because the author
makes no claim that they support or imply
anything, there is no argument.
 b. Expository Passages
Is a kind of discourse that begins with a topic sentence followed by one or
more sentences that develop the topic sentence. If the objective is not to
prove the topic sentence but only to expand it or elaborate it, then there is
no argument.
c. Illustrations
An illustration is an expression involving one or more examples that is
intended to show what something means or how it is done. Illustrations
are often confused with arguments because many illustrations contain
indicator words such as ―thus.
Example: Chemical elements, as well as compounds, can be represented
by molecular formulas. Thus, oxygen is represented by “O2”, water by
“H2O”, and sodium chloride by “NaCl”. This passage is not an argument,
because it makes no claim that anything is being proved.
 d. Explanations
An explanation is an expression that purports to
shed light on some event or phenomenon,
which is usually accepted as a matter of fact. It
attempts to clarify, or describe such alike why
something is happen that way or why
something is what it is.
Example: Cows digest grass while humans
cannot, because their digestive systems contain
enzyme not found in human.
 Cont’d…..
Every explanation is composed of two distinct
components:
 the explanandum and
 explanans.
The explanandum is the statement that describes the event
or phenomenon to be explained, and
the explanans is the statement or group of statements that
purports to do the explaining. In the first example, the
explanandum is the statement ―Cows digest grass while
humans cannot‖ and the explanans is ―their [cows‟]
digestive systems contain enzyme not found in humans.‖
Argument Explanation Accepted fact Claimed to prove
Claimed to shed light o
 e. Conditional Statements
• A conditional statement is an if….then . .
statement.
Example: If you study hard, then you will
score ‘A’ grade. Every conditional
statement is made up of two component
statements. The component statement
immediately following the if is called the
antecedent (if-clause), and the one
following the ―then‖ is called the
consequent (then-clause).
 Cont’d….

Antecedent Consequent

If ------------------ then ----------------------------

Consequent Antecedent

Then ---------------------if --------------------------

 Types of Arguments
 There are two different classes of arguments. These are:
A. Deductive arguments /ye ergitegnanet astesaseb amekniyo
and
B. Inductive arguments. gimtawi
A. Deductive argument
 It incorporating the claim that it is impossible for the
conclusion to be false given that the premises are true.
 It is an argument in which the premises are claimed to
support the conclusion in such a way that it is impossible
for the premises to be true and the conclusion false.
 the conclusion is claimed to follow necessarily
(conclusively) from the premises
 force of certainity
 Cont’d….
Example-1:
All philosophers are critical thinkers.
Socrates is a philosopher.
Therefore, Socrates is a critical thinker.
Example-2:
All African footballers are blacks.
Messi is an African footballer.
It follows that, Messi is black.
 Cont’d….
There are three factors that influence the
decision about the deductiveness or
inductiveness of an argument‘s inferential claim.
These are:
1) The occurrence of special indicator words,
2) The actual strength of the inferential link
between premises and conclusion, and
3) The character or form of argumentation the
arguers use.
 Cont’d….
• Arguments may contain some words that
indicate the arguer‘s
 certainty

 necessarily
 absolutely
 definitely
 Surely
They indicate that the argument should be
taken as deductive.
 Inductiveness indicator words
 probable
 improbable,
 plausible,
 implausible,
 likely,
Almost
 unlikely, and
 reasonable to conclude suggest that an argument is
inductive.
 Instances/forms of Deductive Argumentative
Forms
Three examples of deductive forms or kinds of
argumentation are:
I. Arguments based on mathematics,
II. Arguments from definition, and
III. Syllogisms:
categorical,
 hypothetical, and
disjunctive syllogisms.
 I. Argument based on mathematics
It is an argument in which the conclusions depend on
some purely arithmetic or geometric computation or
measurement.
For example: you can put two orange and three
bananas in a bag and conclude that the bag contains
five fruits.
you can measure a square pieces of land and after
determining it is ten meter on each side conclude that
its area is a hundred square meter.
Since all arguments in pure mathematics are
deductive, we can usually consider arguments that
depend on mathematics to be deductive as well.
 II. Arguments based on definition:
It is an argument in which the conclusion is
claimed to depend merely up on the definition of
some words or phrase used in the premise or
conclusion.
For example:
Angel is honest; it is follows that Angel tells the
truth.
Kebede is a physician; therefore, he is a doctor.
These arguments are deductive because their
conclusions follow with necessity from the
definitions honest and physician.
 III. Syllogisms
Are arguments consisting of exactly two premises and
one conclusion.
a. Categorical syllogism: a syllogism is an argument
consisting of exactly two premises and one
conclusion. It is a syllogism in which the statement
begins with one of the words
 all,
 no and
 some.
Example: All Egyptians are Muslims.
No Muslim is a Christian.
 b. Hypothetical syllogism
• It is a syllogism having a conditional statement for
one or both of its premises.
Example:
If you study hard, then you will graduate with
Distinction.
If you graduate with Distinction, then you will get a
rewarding job.
Therefore, if you study hard, then you will get a
rewarding job. Such arguments are best interpreted as
deductive.
c. Disjunctive syllogism: it is a syllogism having a
disjunctive statement. (I.e. an ―either … or‖ statement.)
 Cont’d…

Example:
Rewina is either Ethiopian or Eritrean.
Rewina is not Eritrean.
Therefore, Rewina is Ethiopian.
As with hypothetical syllogism, such
arguments are usually best taken as
deductive.
 B. Inductive Argument
 Is an argument incorporating the claim that it is
improbable/unbelievable for the conclusion to be
false given that the premises are true.
 the conclusion is claimed to follow only
probably/may be from the premises.
 The premises may provide some considerable
evidence for the conclusion but they do not imply
(necessarily support) the conclusion.
 we might have sufficient condition (evidence) but
we cannot be certain about the truth of the
conclusion.
 Cont’d…..
 conclusion is wrong or unacceptable, where as it
could be correct or acceptable but only based on
probability.
 involve probabilistic reasoning.
Example-1:
Most African leaders are blacks.
Mandela was an African leader.
Therefore, probably Mandela was black.
Example-2:
Almost all women are mammals.
Hanan is a woman.
 Cont’d…
Both of the above arguments are inductive.
 In both of them, the conclusion does not
follow from the premises with strict necessity,
but it does follow with some degree of
probability. That is, the conclusion is claimed
to follow from the premises only probably; or
the premises are claimed to support their
corresponding conclusion with a probability.
If we assume that the premises are true, then
based on that assumption it is probable that the
conclusion is true.
 Instances/examples of Inductive Argumentative
Forms
• In general, inductive arguments are such that the content of the
conclusion is in some way intended to “go beyond” the content
of the premises.
• The premises of such an argument typically deal with some
subject that is relatively familiar, and the conclusion then moves
beyond this to a subject that is less familiar or that little is
known about.
• Several forms:
 predictions about the future,
 arguments from analogy,
 inductive generalizations,
 arguments from authority,
 arguments based on signs, and
 I. Prediction
In a prediction the premises deals with
some known event in the present or the
past and the conclusions moves beyond
this event to some event to relative
future.
For example: one may argue that
because certain clouds develop in the
center of the highland, a rain will fall
within twenty-four hours
 II. Analogy
• It is an argument that depends on the
existence of an analogy or similarity
between two things or state of affairs.
Example: one may conclude, after
observing the similarity of some features of
Computer A and car B: that both are
manufactured in 2012; that both are easy to
access; that Computer A is fast in
processing; it follows that Computer B is
also fast in processing.
 III. An inductive generalization
• It is an argument that proceeds from the
knowledge of a selected sample to some claim
about the whole group. Because the members
of the sample have a certain characteristics, it
is argued that all members of the group have
the same characteristics.
• For example, one may argue that because three
out of four people in a single prison are black,
one may conclude that three-fourth of prison
populations are blacks. This example illustrate
the use of statistics in inductive argumentation.
 Iv. An argument from authority
• it is an argument in which the conclusions rest upon
a statement made by some presumed authority or
witness. Example:
A lawyer, for instance, may argue that the person is
guilty because an eyewitness testifies to that effect
under oath/promise.
All matters are made up of a small particles called
quarks because the University Professor said so.
Because the professor and the eyewitness could be
either mistaken or lying, such arguments are
essentially probabilistic.
 V. Arguments based on sign
it is an argument that proceeds from the
knowledge of a certain sign to the
knowledge of a thing or situation that the
sign symbolizes. Example: one may infer
that after observing ‘No Parking’ sign
posted on the side of a road, the area is not
allowed for parking. But because the sign
might be displaced or in error about the
area or forgotten, conclusion follows only
probably.
 vi. A causal inference
• it is an argument which proceed from the knowledge
of a cause to the knowledge of an effect.
• For example: The cloud is becoming darker and the
thunder is roaming. So, rainfall seems inevitable,
lets go home quickly.
After tasting a piece of chicken and finding it dry and
tough, one might conclude that it had been
overcooked (effect to cause). Because specific
instances of cause and effect can never be known with
absolute certainty, one may usually interpret such an
argument as inductive.
 Scientific arguments
• Arguments that occur in science can be either
inductive or deductive, depending on the
circumstances.
• In general, arguments aimed at the discovery of
a law of nature are usually considered
inductive.
• Another type of argument that occurs in
science has to do with the application of known
laws to specific circumstances. Arguments of
this sort are often considered to be deductive,
but only with certain reservations.
 Cont’d….
• inductive arguments are those that proceed
from the particular to the general, while
deductive arguments are those that proceed
from the general to the particular.
• a deductive argument that proceeds from the
particular to the general. Example:
Three is a prime number.
Five is a prime number.
Seven is a prime number.
Therefore, all odd numbers between two and eight
are prime numbers.
 Evaluating Arguments
Evaluating Deductive Arguments:
 Validity,
Truth, and
Soundness
Validity
If the premises do in fact support the conclusions in this
way the arguments is said to be valid; if not, it is invalid.
 Thus, a valid deductive argument is an argument
such that if the premises are assumed true, it is
impossible for the conclusion to be false.
 the conclusion follows with strict necessity from the
premises.
 Cont’d….
Invalidity
 Is an argument such that if the
premises are assumed true, it is
possible for the conclusion to be
false.
The conclusion does not follow
with strict necessity from the
premises, even though it is
claimed to.
 Cont’d…..

There are four possibilities with respect to

the truth or falsity of the premises and
conclusion of a given argument:
1) True premises and True conclusion,
2) True premises and False conclusion,
3) False premises and True conclusion,
and
4) False premises and False conclusion
 Cont’d…
• Possibility # 1: A combination of True premises
and True conclusion (the first case) allows for
both valid and invalid arguments. Consider the
following examples:
Example-1 (Valid):
All women are mammals. (Tp)
My mother is a mammal. (Tp)
Therefore, my mother is a woman. (Tc)
Example-2 (Invalid):
All philosophers are critical thinkers. (Tp)
Plato was a critical thinker. (Tp)
Therefore, Plato was a philosopher. (Tc)
 Cont’d….

• Possibility # 2: A combination of True

premises and false conclusion (the
second case) allows
only for invalid arguments.
Example-1 (Invalid):
All biologists are scientists. (Tp)
John Nash was a scientist. (Tp)
Therefore, John Nash was a biologist.
(Fc)
 Cont’d…
• Possibility # 3: A combination of False premises
and True conclusion (the third case) allows for
both valid and invalid arguments. Consider the
following examples:
Example-1 (Valid):
All birds are mammals. (Fp)
All women are birds. (Fp)
Therefore, all women are mammals. (Tc)
Example-2 (Invalid):
All birds are mammals. (Fp)
All ostriches are mammals. (Fp)
Therefore, all ostriches are birds. (Tc)
 Cont’d….

• Possibility # 4: A combination of False premises

and False conclusion (the fourth case) allows
for both valid and invalid arguments. Consider
the following examples:
Example-1 (Valid):
All Americans are Ethiopians. (Fp)
All Egyptians are Americans. (Fp)
Thus, all Egyptians are Ethiopians. (Fc)
Example-2 (Invalid):
All birds are mammals. (Fp)
All ants are mammals. (Fp)
Therefore, all ants are birds. (Fc)
 Cont’d…..

• The relationship between the

validity of a deductive argument
and the truth and falsity of its
premises and conclusions
summarized as follows.

Premises Conclusion Validity

True True Valid/invalid
True False Invalid
True Valid/invalid
False Valid/invalid
False False
 Deduction and Soundness
Depending on their
 actual ability, (assuming that they already
have actually accomplished their inferential
claims by being valid),
 to accomplish their factual claims,
deductive arguments can be either sound
or unsound.
A sound argument is a deductive argument
that is valid and has all true premises. Both
conditions must be met for an argument to
 Cont’d….
A deductive argument that does not
actually accomplish its inferential
claim, (that is not valid), called
unsound.
Thus, an unsound argument is a
deductive argument that is either valid
with one or more false premises, or
invalid, or both.
A sound argument, therefore, is what
is meant by a good‘‘ deductive
 Cont’d…..
• Sound Argument = A valid argument
+ All true premises

Evaluating Inductive Arguments:

Strength,
Truth, and
Cogency
 Induction and Strength

• If the premises do in fact support the

conclusions in this way the arguments is
said to be strong.
• Thus, a strong inductive argument is an
argument such that if the premises are
assumed true, it is improbable for the
conclusion to be false.
• A weak inductive argument is an
argument such that if the premises are
assumed true, it is probable for the
conclusions to be false.
 Cont’d…..
Example-1
This barrel contains one hundred apples.
Eighty apples selected at random were found
tasty.
Therefore, probably all one hundred apples
are tasty. (Strong)
Example -2
This barrel contains one hundred apples.
Three apples selected at random were found
tasty.
Therefore, probably all one hundred apples
are tasty. (Weak)
 Strength and Truth Value
• In inductive arguments, there is
no absolutely strong nor
absolutely weak argument.
• Both arguments would be
strengthened or weakened by the
random selection of a larger or
smaller sample.
The relationship between the strength
of an inductive argument and the truth
and falsity of its premises and
conclusions summarized as follows.
Premises Conclusion Strength
True True Strong/Weak
True False Weak
False True Strong/Weak
False False Weak/Weak
 Induction and Cogency
Depending on their
 actual ability,
 factual claims,
Inductive arguments can be either cogent or
uncogent.
Cogent:/arki is an inductive argument that is
strong and has all true premises.
Uncogent/erkata yemayset is an inductive
argument that is either strong with one or more
false premises, or weak, or both.
Cogent Argument = A strong argument + All true
 Summary

Argument

Deductive Inductive

Valid Invalid Weak Strong

Unsou Uncoge
Sound nd Unsound Uncogent Cogent nt
 CHAPTER THREE
LOGIC AND LANGUAGE
 CHAPTER FOUR
BASIC CONCEPTS OF CRITICAL THINKING
Lesson 1: Meaning of Critical Thinking
 Critical means involving or exercising skilled judgment or
observation.
 Critical thinking means thinking clearly and intelligently.
 Critical thinking is the general term given to a wide range
of cognitive skills and intellectual dispositions needed to
effectively identify, analyze, and evaluate arguments and
truth claims.
 Moreover, it helps to discover and overcome personal
preconceptions and biases; to formulate and present
convincing reasons in support of conclusions; and to make
reasonable, intelligent decisions about what to believe and

what to do.
• Being smart and intelligent is not sufficient.
• Critical thinking is a process or journey that helps
us to arrive at the most useful, helpful, and most
likely destinations when evaluating claims for
scientific truth.
• Critical thinking is thinking clearly, thinking fairly,
thinking rationally, thinking objectively, and thinking
independently.
• It is a process that hopefully leads to an impartial
investigation of the data and facts that remains not
swayed by irrelevant emotions.
• Therefore, the aim of critical thinking is to arrive at
well-reasoned, considered, and justifiable
• The American philosopher, John
Dewey, has defined critical thinking
as an active, persistent, and grounds.
• Active: one in which you think things
through for yourself, raise questions
yourself, find relevant information
yourself and so on, rather than
learning in a largely passive way
from someone else
• Persistent and careful consideration: critical
thinking with the kind of unreflective thinking we
all sometimes engage in.
• For example, we sometimes jump to a
conclusion or make a quick decision without
thinking about it. Of course, sometimes, we
may have to do this because we need to decide
quickly or the issue is not important enough to
warrant careful thought, but we often do it when
we ought to stop and think – when we ought to
persist a bit.
• Grounds: which support‘ a belief and the ̳further
conclusions to which it tends‘.
• Matters are the reasons we have for
believing something and the implications
of our beliefs.
• It is no exaggeration to say that critical
thinking attaches huge importance to
reasoning, to giving reasons and to
evaluating reasoning as far as
possible. There is more to it than that, but
skilful reasoning is a key element.
• Edward Glaser defined critical thinking as:
(1) an attitude of being disposed to
consider in a thoughtful way the
problems and
subjects that come within the range of
one’s experience;
(2) knowledge of the methods of logical
enquiry and reasoning; and
(3) some skill in applying those methods.
• Robert Ennis: critical thinking as
reasonable, reflective thinking that is
focused on deciding what to believe or
do.
• What we learn from Ennis‘ definition is
that when we make a decision, we
should be serious about it. The
decision may be about purchasing a
phone, or it may be about choosing a
department, or any
other issues. But we should employ
• Richard Paul: Critical thinking is that mode
of thinking – about any subject, content or
problem – in which the thinker improves
the quality of his or her thinking by
skillfully taking charge of the structures
inherent in thinking and imposing
intellectual standards upon them. Paul
associates critical thinking with.
• Michael Scriven has defined critical thinking as skilled
and active interpretation and evaluation of observations and
communications, information and
argumentation. He argued that critical thinking is an academic
competency akin to reading and
writing and is of similarly fundamental importance.
• Scriven‘s: defines critical thinking as a ̳ skilled‘ activity for
reasons similar to those mentioned above. He points out that
thinking does not count as critical merely because it is intended
to be, any more than thinking counts as scientific simply
because it aims to be. To be critical, thinking has to meet
certain standards, (clarity, relevance, reasonableness and so
on), and one may be
more or less skilled at this. He defined critical thinking as an
̳active‘ process, partly because it
involves questioning and partly because of the role played by
• Critical thinking is sometimes referred to as ‘critic-
creative‘ thinking. This word is the
combination of two words:
• critical and creative. There are two related
reasons for this.
• ‘Critical thinking‘ is sometimes thought to sound
rather negative, as though one‘s only interest is in
adversely criticizing other people‘s arguments
and ideas.
• Creative: be good at evaluating arguments and
ideas, one often has to be very imaginative and
creative about other possibilities, alternative
considerations, different options and so on.
 Standards of Critical Thinking
• Among the most important of these critical
standards are
clarity,
 precision,
accuracy,
relevance,
consistency,
logical correctness,
completeness, and
fairness.
 a. Clarity
refers to clear understanding of concepts and
clearly expressing them in a language
free of obscurity and vagueness.
 When we construct argument, we should take
into consideration or pay close attention to clarity.
clarity is a gateway standard.
lack of clarity is due to
 laziness,
 carelessness, or
 a lack of skill.
 misguided effort to appear clever, learned, or
profound.
 b. precision/correctness
It is a matter of being exact, accurate and
careful. Most ideas are vague and
obscures though we think we have
precise understanding of them.
When we try to meticulous/fussy these
ideas, we will find that they are imprecise.
pay close attention to details.
Everyone recognizes the importance of
precision in specialized fields such as
medicine, mathematics, architecture, and
 c. accuracy
It is about correct information.
Critical thinking should care a lot about
genuine information.
If the ideas and thoughts one processes
are not real, then once decision based on
wrong and false information will likely to
result in distorting realities.
John Rawls, “truth is the first virtue of
systems of thought”.
having and getting true information.
‘Garbage in, garbage out’.
• Critical thinkers do not merely value
the truth; they also have a passion for
accurate, timely information.
d. Relevance
Is a question of connections (ideas and
information).
Critical thinkers do not collect any
information; they focus and carefully
choose only the information that has
logical relation with the ideas at hands.
 E. Consistency/uniformity
It is about the quality of always behaving in the
same way or of having the same opinions or
standards.
It is easy to see why consistency is essential to
critical thinking. Logic tells us that if a person
holds inconsistent beliefs, at least one of those
beliefs must be false.
Critical thinkers prize truth and so are
constantly on the lookout for inconsistencies,
both in their own thinking and in the arguments
and assertions of others.
 f. Logical correctness
 To think logically is to reason correctly;
 to draw well-founded conclusions from the
beliefs held.
 To think critically, we need accurate and well
supported beliefs.
 we need to be able to reason from those beliefs to
conclusions that logically follow from them.
 the combinations of thoughts are mutually
supporting and make sense in combination, the
thinking is logical.
 When the combination is not mutually supporting,
is contradictory in some sense, or does not make
sense the combination, is not logical.
 g. Completeness
prefer deep and complete thinking to
shallow and superficial thinking.
Of course, there are times when it is
impossible or inappropriate to discuss an
issue in depth; no one would expect, for
example, a thorough and wide-ranging
discussion of the ethics of the right to self-
determination in a short newspaper editorial.
 However, thinking is better when it is deep
rather than shallow, thorough rather than
superficial.
 h. Fairness
It implies the treating of all relevant viewpoints
alike without reference to one‘s own feelings or
interests.
open minded,
 impartial, and
 free of distorting biases and preconceptions
 free of prejudge issues,
 to stereotype outsiders,
 free of own self-interest or the interests of their
nation or group.
 Codes of Intellectual Conduct for Effective
Discussion/ Principles of Good Argument
A. The Structural Principle
It requires that one who argues for or against a
position should use an argument that meets the
fundamental structural requirements of a well-
formed argument.
Such an argument does not use reasons that
contradict each other, that contradict the conclusion,
or that explicitly or implicitly assume the truth of the
conclusion.
Neither does it draw any invalid deductive
inferences. The first criterion used in determining
whether an argument is a good one is the
requirement that it be structurally sound.
 B. Relevance Principle
It requires that one who presents an argument
for or against a position should set forth only
reasons whose truth provides some evidence
for the truth of the conclusion.
The premises of a good argument must
be relevant to the truth or merit of the
conclusion.
A premise is relevant if its acceptance
provides some reason to believe, counts
in favor of, or has some bearing on the
truth or merit of the conclusion.
 C. The Acceptability Principle
This principle requires that one who presents
an argument for or against a position should
provide reasons that are likely to be accepted
by a mature, rational person and that meet
standard criteria of acceptability.
A reason is acceptable if it is the kind of claim
that a rational person would accept in the face
of all the relevant evidence available. Some
people believe that the acceptability principle
should be replaced by the truth principle to
connote the idea that premises should be true
to be acceptable.
 D. The Sufficiency Principle
It requires that one who presents an argument
for or against a position should attempt to
provide relevant and acceptable reasons of the
right kind, number and weight to justify the
acceptance of the conclusion.
F. The Rebuttal Principle
This principle requires that one who presents an
argument for or against a position should
include in the argument an effective rebuttal to
all anticipated serious criticisms of the argument
that may be brought against it or
against the position it supports.
 Principles of Critical Thinking
1. Fallibility principle
This principle requires that each
participant in a discussion of a disputed
issue should be willing to accept the fact
that he or she is fallible, which means that
one must acknowledge that one‘s own
initial view may not be the most defensible
position on the question.
genuinely interested in the kind of honest
inquiry that may lead to a fair resolution of
the issue.
 2. The Truth Seeking Principle
This principle requires that each participant
should be committed to the task of earnestly
searching for the truth or at least the most
defensible position on the issue at stake.
willing to examine alternative positions
seriously, look for insights in the positions of
others, and allow other participants to
present arguments for or raise objections to
any position held on an issue.
 3. The Clarity Principle
free of any kind of linguistic confusion and
clearly separated from other positions and
issues.
 Any successful discussion of an issue
must be carried on in language that all the
parties involved can understand.
Even if what we have to say is perfectly
clear to ourselves, others may not be able
to understand us.
 4. The Burden of Proof Principle
It requires that the burden of proof for any
position usually rests on the participant
who sets forth the position.
 If, and when, an opponent asks, the
proponent should provide an argument for
that position.
Just as a person is generally held
accountable for his or her own actions,
one who makes a positive or negative
claim about something has what is called
the burden of proof.
 5. The Principle of Charity/contribution
set forth in support of one of the options.
it requires that if a participant‘s argument is
reformulated by an opponent, it should be
carefully expressed in its strongest possible
version that is consistent with what is
believed to be the original intention of the
arguer.
If there is any question about that intention
or about any implicit part of the argument,
the arguer should be given the benefit of any
doubt in the reformulation and/or, when
 6. The Suspension of Judgment Principle
• This principle requires that if no position is defended
by a good argument, or if two or more positions seem
to be defended with equal strength, one should, in
most cases, suspend judgment about the issue.
• If practical considerations seem to require a more
immediate decision, one should weigh the relative
benefits or harm connected with the consequences of
suspending judgment and decides the issue on those
grounds.
• avoid the psychological fright of making a
difficult decision or of moving into unfamiliar
territory.
 7. The Resolution Principle
This principle requires that an issue
should be considered resolved if the
argument for one of the alternative
positions is a structurally sound, one
that uses relevant and acceptable
reasons that together provide sufficient
grounds to justify the conclusion and
that also include an effective rebuttal to
all serious criticisms of the argument
and/or the position it supports.
 Characteristics of Critical Thinking /or Basic Traits
 Are honest with themselves,
 acknowledging what they don't know,
 recognizing their limitations, and
 being watchful of their own errors.
 Strive for understanding,
 keep curiosity alive,
 remain patient with complexity, and
 are ready to invest time to overcome confusion.
 Base judgments on evidence rather than personal
preferences,
 deferring judgment whenever evidence is insufficient.
 They revise judgments when new evidence reveals
error.
Are interested in other people's ideas
willing to read and listen attentively, even
when they tend to disagree with the other
person.
Recognize that extreme views (whether
conservative or liberal) are seldom
correct, so they avoid them, practice fair-
mindedness, and seek a balance view.
Practice restraint, controlling their
feelings rather than being controlled by
them, and thinking before acting.
 Basic Traits of Uncritical Thinkers
 Pretend they know more than they do, ignore their limitations,
and assume their views are error-free.
 Regard problems and controversial issues as nuisances or
threats to their ego.
 Are inpatient with complexity and thus would rather remain
confused than make the effort to understand.
 Base judgments on first impressions and gut reactions. They
are unconcerned about the amount or quality of evidence and
cling to their views steadfastly.
 Are preoccupied with themselves and their own opinions, and
so are unwilling to pay attention to others' views. At the first
sign of disagreement, they tend to think, "How
can I refute this?"
 Ignore the need for balance and give preference to views that
support their established views.
 Barriers to Critical Thinking
Five of these impediments that play an especially
powerful role in hindering critical thinking:
egocentrism,
socio-centrism,
unwarranted assumptions,
relativistic
thinking, and
wishful thinking.
 1. Egocentrism
Egocentrism is the tendency to see reality as
centered on oneself.
 Egocentrics are selfish, self-absorbed people who
view their interests, ideas, and values as superior to
everyone else‘s.
All of us are affected to some degree by egocentric
biases.
Egocentrism can manifest itself in a variety of ways.
Two common forms this are self-interested thinking
and the superiority bias.
Self-interested thinking is the tendency to accept
and defend beliefs that harmonize with one‘s
self-interest.
 2. Socio-centrism
paralyze the critical thinking ability of most
people including intellectuals is socio-
centrism.
 It is group-centered thinking.
 Socio-centrism can distort critical thinking
in many ways. Two of the most important
are group bias and conformism.
Group bias is the tendency to see one‘s
own group (nation, tribe, sect, peer group,
and the like) as being inherently better
Most people absorb group bias
unconsciously, usually from early
childhood.
Clearly, this kind of ‘mine-is-better’
thinking lies at the root of a great deal of
human conflict, intolerance, and
oppression.
Conformism refers to our tendency to
follow the crowd - that is, to conform (often
unthinkingly) to authority or to group
 3. Unwarranted Assumptions and Stereotypes
An assumption is something we take for
granted - something we believe to be true
without any proof or conclusive evidence.
Almost everything we think and do is
based on assumptions.
Unwarranted assumptions, however, are
unreasonable.
An unwarranted assumption is something
taken for granted without good reason.
Such assumptions often prevent our
stereotypical conceptions will often
be false or misleading.
stereotypes are arrived at through a
process known as hasty
generalization, in which one draws a
conclusion about a large class of
things(in this case, people) from a
small sample.
 4. Relativistic Thinking
Relativism is the view that truth is a matter of
opinion.
There are two popular forms of relativism:
subjectivism and cultural relativism.
Subjectivism is the view that
 truth is a matter of individual opinion. an
individual believes is true, is true for that
person, and
 there is no such thing as ―objective or
absolute truth, i.e., truth that exists independent
of what anyone believes.
• cultural relativism: This is the view that truth is a
matter of social or cultural opinion. In other
words, cultural relativism is the view that what is
true for person A is what person A‘s culture or
society believes is true.
• most people in a society or culture believe to be
true.
common form of relativism
• is moral relativism. Like relativism generally,
moral relativism comes in two major forms: moral
subjectivism and cultural moral relativism. Moral
subjectivism is the view that what is morally right
and good for an individual,
• Cultural moral relativism attractive is that it
seems to support the value of tolerance.
Throughout history, terrible wars, persecutions,
and acts of religious and cultural imperialism
have been perpetrated by people who firmly
believed in the absolute righteousness of their
moral beliefs and practices.
• Cultural moral relativism seems to imply that
we must be tolerant of other cultures‘ moral
beliefs and values.
 5. Wishful Thinking
• Is a state of believing something not because you
had good evidence for it but simply because you
wished it were true.
• Throughout human history, reason has done
battle with wishful thinking and has usually come
out the loser. People fear the unknown and invent
comforting myths to render the universe less
hostile and more predictable. They fear death and
listen credulously to stories of healing crystals,
quack cures, and communication with the dead.
They fantasize about possessing extraordinary
personal powers and accept uncritically accounts
of psychic prediction and levitation
 Benefits of Critical Thinking
• skills and Dispositions
 Understanding the arguments and beliefs of others.
 Critically evaluating those arguments and beliefs.
 Developing and defending one‘s own well-
supported arguments and beliefs.
 Critical Thinking in Life and classroom
Critical thinking is valuable in many contexts
outside the classroom.
 help us avoid making foolish personal decisions.
 avoid such mistakes by teaching us to think about
important life decisions more carefully, clearly, and
logically.
 promoting democratic processes by reducing
many of today‘s most serious societal
problems.
 environmental destruction,
 poverty, ethnic conflicts,
 decaying the morality of societies,
 high level of corruption ,
 violating basic human rights,
 displacement, etc..
 CHAPTER THREE
Fallacies
What are fallacies?
It comes from a Latin word called ‘fallo’,
‘fallacia’ meaning create illusion, to cheat, to
bribe.
Arguments could be logically correct or incorrect.
It is a deficiency or logical problem that occurs
in an argument for various reasons, other than
merely false premises.
Is an error or defect or mistake committed in
arguments.
 is faulty reasoning.
• refers to a logical defect or flaw or
fault that a certain argument exhibits
in its structural arrangement or
reasoning process, or in the
contents of its statements used as
premises or a conclusion, for various
reasons, other than merely false
premises.
• There are four general criteria of a
good argument, which specifically
evaluate the
relevance,
acceptability,
Sufficiency ground, and
rebuttablity of the premises.
• Relevant: if its acceptance provides some reason to
believe, counts in favor of, or makes a difference to the
truth or falsity of the conclusion. Otherwise, it is irrelevant.
• Acceptable: if it is a reason, that the skeptic is likely to
accept, or that a rational person is ought to accept, or
agreed on. However, an argument may not be good, even
though its premises may be relevant and acceptable.
• Sufficient: enough in number, kind and weight.
• Effective rebuttal: (refutation, or disproof) to the
strongest arguments against one‘s conclusion and also
perhaps to the strongest arguments in support of the
alternative position.
 1.2 Types of Fallacies
Depending on the kind of the problems or defects they
contain, fallacies are usually divided into two groups:
These are:
A. Formal fallacies and
B. Informal fallacies
A. Formal fallacy: committed due to a structural defect of
argument is known as a formal fallacy. Because the problem that
causes them is a structural defect, formal fallacies may be
identified through mere inspection of the form or structure of an
argument.
Are found only in deductive arguments that have identifiable
forms, such as
 categorical syllogisms,
 disjunctive syllogisms, and
 hypothetical syllogisms
B. An informal fallacy: is a fallacy, which is
committed due to a defect in the very content of an argument.
Because they have the ability to hide their true argumentative
forms.
 Now a day more than 100 fallacies have been invented.
Groups of informal fallacies
According to Aristotle, there are twenty-two informal
fallacies into five groups:
1. fallacies of relevance,
2. fallacies of weak induction,
3. fallacies of presumption,
4. fallacies of ambiguity, and
5. fallacies of grammatical analogy. 4 and 5 are
 1. Fallacies of Relevance
• the arguments, in which they occur,
have premises that are logically
irrelevant to the conclusion.
• Yet the premises are relevant
psychologically, so the conclusion
may seem to follow from the
premises, even though it does not
follow logically.
• the connection between premises and
conclusion is emotional.
 Types of fallacies of relevance
i. Emotional appeal fallacies
ii. Wrong rebuttal fallacy and
iii. Wrong reasoning fallacies
i. Emotional appeal fallacies
There are three emotional appeal fallacies.
a. Appeal to Force (Argumentum ad Baculum: Appeal to the-
Stick)
it occurs when a conclusion defended by a threat to the well-
being of those who do not accept the conclusion. Example- 1:
Father to son, “my boy, you must study hard, if not you will be
either a criminal or a beggar.
Example-2: Mr. Kebde you accused me of fraud and
embezzlements. You have to drop the charge you filed against
me. You have to remember that I am your ex-boss; I will torture
both you and your family members if you do not drop your
case. Got it?
b. Appeal to Pity (Argumentum ad Misericordiam)
Attempt to support a conclusion merely by evoking pity
in one‘s audience when the statements that evoke the
pity are logically unrelated to the conclusion.
Example:The Headship position in the department of
accounting should be given to Mr. Oumer Abdulla.
Oumer has six hungry children to feed and his wife
desperately needs an operation to save her
eyesight.
c. Appeal to the People (Argumentum ad Populum)
Nearly everyone wants to be loved, esteemed,
admired, valued, recognized, and accepted by
others.
 Feeling of being part of community and
belongingness are some of the most important
humans needs. The appeal to the people
strikes these desires and needs to get
acceptance for conclusion.
 Is an attempt to persuade a person (or group)
by appealing to these desires and need.
• Example: lots of people accept it, or in urging the
rejection of the position on the ground that very few
people accepted it.
Types of appeal to people
Two approaches are involved in appeal to
people fallacy:
A. Direct and
B. indirect: when an arguer, addressing a
large group of people, excites the
emotions and enthusiasm of the crowd to
win acceptance for his or her conclusion.
B. indirect approach: the arguer aims his or her appeal not at the
crowd/mass as a whole but at one or more individuals separately,
focusing on some aspect of their relationship to the crowd for one’s
own advantage.
 Is very common in most advertising industries. There are three
recognizable forms in indirect approach:
 Bandwagon: eg. “A film is a good one, b/se there are long lines of
people waiting to see it.”
 Vanity: related to products with celebrities. eg. who is going to
wear this new fashin dress, a dress worn by the famous Aster
Aweke in her new Year’s Sheraton Hotel’s show.
 Snobbery: persons with high social position like kings, queens
and princes. eg. The newly produced Gebeta Guder wine is not for
everyone to drink. But you are different from
other people, aren’t you? Therefore, the newly produced Gebeta
 ii. Wrong rebuttal fallacies
• Fail to provide an effective criticism,
opposition, refutation or disapproval of the
position or the view point of others.
• The second person attempts to refute the first
person’s idea without providing logical
evidences.
Types of wrong rebuttal fallacies of relevance
There are three.
a) Argument against the person
b) Strawman and
c) Red herring
 a) Argument against the Person (Argumentum ad Hominem)
• This fallacy always involves two arguers.
• One of them advances (either directly
orimplicitly) a certain argument and
• the other then responds by directing his
or her attention not to the first person‘s
argument but to the first person himself.
• When this occurs, the second person is
said to commit an argument against the
person.
 Types of against the person fallacy
• Ad hominem abusive
• Ad hominem circumstantial and
• Ad hominem tu quoque (you too)
Ad hominem abusive: the second person responds to the
first person‘s argument by verbally abusing the first
person. Example;
In defending animal rights, Mr. Abebe argues that the
government should legislate a minimum
legal requirement to any individuals or groups who want to
farm animals. He argues that this is
the first step in avoiding unnecessary pain on animals and
protecting them from abuse. But we
should not accept his argument because he is a divorced
drunk person who is unable to protect
 Ad Hominem Circumstantial Fallacy
• Heaping verbal abuse on his or her opponent,
the respondent attempts to discredit the
opponent‘s argument by alluding to certain
circumstances that affect the opponent.
• Example; Haileselassie I of Ethiopia argued in
the League of Nations that member states
should give hand to Ethiopia to expel the fascist
Italy from the country. But the member states
should not listen to the king. Haileselassie I
argue in this way because he wants to resume
his power once the Italian are expelled from
Ethiopia.
 Tu Quoque (You too) Fallacy
• Is committed when we say that a person’s
claim is false because it’s inconsistent or
contrary with something else the person has
said or done before. Example;
Patient to a Doctor: Look Doctor, you
cannot advise me to quit smoking cigarette
because you yourself is a smoker. How do
you advise me to quit smoking while you
yourself is smoking?
 b. Straw man fallacy
• The straw man fallacy is committed when an arguer
distorts an opponent‘s argument for the
purpose of more easily attacking it, demolishes the
distorted argument, and then concludes that
the opponent‘s real argument has been demolished.
Example; Mr. Belay believes that ethnic federalism
has just destroyed the country and thus it should be
replaced by geographical federalism. But we should
not accept his proposal. He just wants to take the
country back to the previous regime. Geographical
federalism was the kind of state structure during
Derg and monarchical regime. We do not want to go
back to the past. Thus, we should reject Mr. Belay‟s
proposal.
 c. Red herring fallacy/maskeyes/
Is committed when the arguer diverts
the attention of the reader or listener by changing
the subject to a different but sometimes subtly
related one. Example;
Teferi; do you know, Asfaw what Almaz has
got ‘A’ in logic.
Asfaw; you knows that Aster always wears
miniskirts and she attracts teachers
with half-necked body.
 iii. Wrong/irrelevant/ reasoning fallacies
• There are two types.
a) Fallacy of Accident and
b) Fallacy of missing the point(ignoratio elenchi)
c) Fallacy of Accident: committed when a general
rule is applied to a specific case it was not intended
to cover. Typically, the general rule is cited (either
directly or implicitly) in the premises and then
wrongly applied to the specific case mentioned in
the conclusion.
Example:
Freedom of speech is a constitutionally guaranteed
right. Therefore, John Q. Radical should not
be arrested for his speech that incited the riot last
 b) Fallacy of missing the point (ignoratio elenchi)

• illustrates a special form of irrelevance.

• It occurs when the premises of an argument support one
particular conclusion, but then a different conclusion, often
vaguely related to the correct conclusion, is drawn.
Example;
The world is in the process of globalizing more than ever.
The world economy is becoming more and more
interconnected. Multinational companies and supra national
institutions are taking power from local companies and
national governments. The livelihood of people is randomly
affected by action and decision made on the other side of
the planet and this process benefits only the rich nations at
the expense of the poor. What should be done? The answer
is obvious:
poor nations should detach themselves from the process.
 2. Fallacies of weak induction

• violates the principles of sufficiency, which states that

whenever a person presents an argument for or
against a position, he/she should attempt to provide
relevant and acceptable reasons of the right kind, that
together are sufficient in number and weight to justify
the acceptance of the conclusion.
• There are different kinds of fallacies of weak induction
i. Appeal to Unqualified Authority,
ii. Hasty Generalization,
iii. False Cause,
iv. Weak Analogy,
v. Slippery Slope, and
vi. Appeal to Ignorance.
 i. Appeal to Unqualified Authority (Argumentum ad
Verecundiam)

• It is frequently the case in personal, social, and political

deliberations that one does not know all
the relevant facts. One may get information from another
person who has the facts.
Example: 1
The famous artists, artist Woriku said that Vera Pasta is the
most nutritious food. So Vera pasta
must be the most nutritious food.
Example: 2
Prof. Kebede, who is an expert in animal science, argued that,
in more complex societies, there is higher level of division of
labor and in less complex societies, there is less division of
 Ii. Hasty Generalization (Converse Accident)
• Is an argument that proceeds from the
knowledge of a selected sample to some claim
about the whole group. Because the members
of the sample have a certain characteristic, it is
argued that all the members of the group have
that same characteristic.
Example; Addis Zemen Gazeta carried an
interview to know the reading skill among young
people. It has found out that, among ten young
people it interviewed, none of them read a book
for the last two years. The conclusion is obvious:
all young people in the country do not have the
culture of reading books.
 iii. Causal fallacies

• kind of argument which argues either from the

knowledge of causes to the knowledge of
effects or from the knowledge of the effect to
the knowledge of causes. In such argument two
things are presented as having causal
connection.
• There are three varieties of false cause fallacy.
1. Post hoc ergo propter hoc fallacy
2. Non causa pro causa fallacy or not the cause for
the cause and
3. Oversimplified cause fallacy.
 i. Post hoc ergo propter hoc fallacy

Event A causes event B in any particular

case, is that there is a statistical correlation
between A and B: event A and event B are
correlated.
• After this, therefore, because of this
• After this, therefore, the consequense of this
• Example, if a significant statistical correlation is
found between reduced incidence of heart
attacks and drinking of red wine, the tentative
conclusion may be drawn as a hypothesis is
that drinking red wine is the cause of the
reduction in heart attacks.
 ii. Non causa pro causa fallacy
• This variety is committed when what is
taken to be the cause of something is not
really the cause at all and the mistake is
based on something other than mere
temporal succession. Example; 1
• What makes Africans poor is b/se they are
black people.
 iii. Oversimplified cause fallacy
• occurs when a multitude of causes is
responsible for a certain effect but the arguer
selects just one of these causes and represents
it as if it were the sole cause. Example;
• In Ethiopia, the grades of fresh students in
universities have been dropping for several years.
What accounts for this? Well, during these same
years, the average time students spend on
facebook (per day) has increased. So, the cause is
obvious: students are spending much of their time
surfing on facebook when they need to be reading
instead.
 iv. Weak analogy
• a very commonly used kind of case-based
reasoning, where one case is held to be similar
to another case in a particular respect. Since
the one case is held to have a certain property,
then the other case, it is concluded, also has
the same property (because the one case is
similar to the other). Example.
After ingesting one milligram of substance
alpha per day for ninety days, white mice
developed genetic abnormalities. Since white
mice are similar in many ways to humans, it
follows that substance alpha probably
produces genetic abnormalities in humans.
 v. Slippery Slope Fallacy
• s a species of negative reasoning from consequences,
used where two parties are deliberating together and one
warns the other not to take a contemplated action,
because it is a first step in a sequence of events that will
lead to some horrible outcome. Example;
Against cultural, social and religious norms of Ethiopia, a
Chinese firm was authorized to run donkey slaughter
house in Bishoftu. But this company should be closed. If
donkeys are continuously slaughtered and exported, then
Ethiopian who works in the abattoir will start to eat donkey
meat. Then members of the family of these workers will be
the next to eat donkey meat. This gradually leads their
neighbors and the village to accept the same practice.
Finally, the whole country will follow which in turn leads to
the total collapse of Ethiopian food culture.
 vi. Appeal to Ignorance (Argumentum ad Ignorantiam)

• When the premises of an argument state that

nothing has been proved one way or the other
about something, and the conclusion then
makes a definite assertion about that thing.
Example; People have been trying for centuries
to provide conclusive evidence for the claims
that Haileselassie I of Ethiopia is the
descendant of King David of Israel and no one
has ever succeeded. Therefore, we must
conclude that Haileselassie I of Ethiopia is not
the descendant of King David of Israel.
 3. Fallacies of Presumption
• The fallacies of presumption include
A. begging the question,
B. complex question,
C. false dichotomy, and
D. suppressed evidence.
These fallacies arise not because the
premises are irrelevant to the conclusion or
provide insufficient reason for believing the
conclusion but because the premises
presume what they purport to prove.
 A. Begging the Question (Petitio Principii)
• Is committed whenever the arguer creates the
illusion that inadequate premises provide adequate
support for the conclusion by leaving out a possibly
false (shaky) key premise, by restating a possibly
false premise as the conclusion, or by reasoning in
a circle. Examples:
• Murder is morally wrong. This being the case, it
follows that abortion is morally wrong.
• Of course humans and apes evolved from common
ancestors. Just look how similar they are.
• It’s obvious that the poor in this country should be
given handouts from the government. After
all, these people earn less than the average citizen.
 B. Complex Question
• committed when two (or more) questions are
asked in the guise of a single question and a
single answer is then given to both of them.
• Every complex question presumes the existence
of a certain condition. When the respondent‘s
answer is added to the complex question, an
argument emerges that establishes the
presumed condition by saying yes/ no.
Example:
• Have you stopped cheating on exams?
• Where did you hide the corpse of the person you
killed?
 C. False Dichotomy
• Committed when a disjunctive (either . . . or)
premise presents two unlikely alternatives as if
they were the only ones available, and the
arguer then eliminates the undesirable
alternative, leaving the desirable one as the
conclusion. Example;
• Classical democracy is originated either from
the Gada System or from Athens.
• Classical democracy did not originated from
ancient Athens.
• Thus, it must originate from the Gada System.
 D. Suppressed evidence.

• The requirement of true premises includes the

proviso that the premises not ignore
some important piece of evidence that
outweighs the presented evidence and entails a
very different conclusion.
• Example:
Somalia is a good place for investment for the
following reasons. First there are cheap raw
materials. Second there is cheap labor. Third
there is good market for our product. Forth there
is a port that helps us to export our product.
Thus, we have to consider investing in Somalia.
But there is no peace and stability in Somalia
 Linguistic fallacies
• There are two kinds of Linguistic fallacies.
4. Fallacies of Ambiguity and
5. Grammatical Analogy
A. Fallacies of Ambiguity: it includes
i. Equivocation and
ii. Amphiboly.
These fallacies arise from the occurrence of some form
of ambiguity in either the premises or the conclusion (or
both). An expression is ambiguous if it is susceptible to
different interpretations in a given context. When the
conclusion of an argument depends on a shift in
meaning of an ambiguous word or phrase or on the
wrong interpretation of an ambiguous statements, the
argument commits a fallacy of ambiguity.
 i. Equivocation
•
The fallacy of equivocation occurs when the conclusion
of an argument depends on the fact that a word or
phrase is used, either explicitly or implicitly, in two
different senses in the argument. Such arguments are
either invalid or have a false premise, and in either case
they are unsound.
Examples:
 Some triangles are obtuse. Whatever is obtuse is
ignorant. Therefore, some triangles are
ignorant.
 Any law can be repealed by the legislative authority. But
the law of gravity is a law. Therefore,
the law of gravity can be repealed by the legislative
 ii. Amphiboly
• Occurs when the arguer misinterprets an ambiguous
statement and then draws a conclusion based on this
faulty interpretation. The original statement is usually
asserted by someone other than the arguer, and the
ambiguity usually arises from a mistake in grammar or
punctuation - a missing comma, a dangling modifier, an
ambiguous antecedent of a pronoun, or some other
careless arrangement of words. Examples;
• The tour guide said that standing in Mesqel Square, the
new federal police building could easily be seen.
It follows that the Empire State Building is in Greenwich
Village.
• Habtom told Megeressa that he had made a mistake. It
follows that Habtom has at least the courage to
admit his own mistakes.
 5. Fallacies of Grammatical Analogy
• The fallacies of grammatical analogy are
grammatically analogous to other
arguments that are good in every respect.
Because of this similarity in linguistic
structure, such fallacious arguments may
appear good yet be bad.
There are two forms of Fallacies of Grammatical
Analogy
A. Composition and
B. Division
 A. Composition
• committed when the conclusion of an argument
depends on the erroneous transference of an attribute
from the parts of something onto the whole. In other
words, the fallacy occurs when it is argued that
because the parts have a certain attribute, it follows
that the whole has that attribute too and the situation is
such that the attribute in question cannot be
legitimately transferred from parts to whole. Examples;
• Each player on this basketball team is an excellent
athlete. Therefore, the team as a whole is excellent.
• Each atom in this piece of chalk is invisible. Therefore,
the chalk is invisible.
• Sodium and chlorine, the atomic components of salt,
are both deadly poisons. Therefore, salt is a deadly
 B. Division
• The fallacy of division is the exact reverse of
composition. As composition goes from parts to
whole, division goes from whole to parts. The fallacy
is committed when the conclusion of an
argument depends on the erroneous transference of
an attribute from a whole (or a class) onto its parts (or
members). Examples;
• Salt is a non-poisonous compound. Therefore, its
component elements, sodium and chlorine, are
non-poisonous.
• The Royal Society is over 300 years old. General
Merid Hussein is a member of the Royal Society.
Therefore, General Merid Hussein is over 300 years
old.
 Cont’d…
• This piece of chalk has mass.
Therefore, the atoms that compose
this piece of chalk have mass.