INTRODUCTION

TO

LOGIC

A MODULAR APPROACH

Andrea Magtuto*

Babylyn Cruz

Irish Garduce

Myn Mae Sales

John Timario

Module 1

UNDERSTANDING PHILOSOPHY

AND ITS BRANCHES

Basic to philosophy is the principle that

everything in the world has cause. Nothing

comes into the world without a cause. There is

a cause why you are in the classroom listening

to a lecture, why you feel hungry, why people

die and even why a leaf falls from the branch

of a tree. Christian philosophy adheres to the

basic tenet that if a chain of causes is followe,

one will ultimately reach

Prime mover known to believers as God.

Generally, philosophy ask questions about

the universe and mans place in it. What

generally comprises the world? Is it entirely

physical in its composition and process? What

makes philosophy different from other

disciplines is the fact that if other branches

have no answer to the aforementioned question

Unit 1

THE ESSENCE

OF

PHILOSOPHY

Philosophy

The ancient definition is the traditional

concept of philosophy which comes from the

Greek terms philos meaning love and

sophia: means wisdom or knowledge

Main points of philosophy

1. Philosophy is a science

2. Science of things

3. Ultimate principles and causes

4. Known only by natural reason

Philosophy is a science

Science is a systematized body of

knowledge based on evidence. Philosophy is a

science and like all other branches of science,

it is also based on evidence. This means that

philosophy is not based on speculations,

opinions or mere conjecture

Science of things

Philosophy is concerned with everything

in the world as far as the human mind can

reach, from the microscopic particles to the

giant mountains. Nothing is exempted, and all

things are the concern of philosophy.

Ultimate Principles and causes

All branches of science have their own

special focus, Zoology, for instance, is

concerned with animals; botany deals with

plants; sociology studies people or society and

its functions, etc. Philosophy explores the

ultimate or final cause of a thing..

Known only by natural reason

A dissecting instrument is used in

studying the internal organs of a forg.

Philosophy does not use a piece of equipment,

a laboratory device, etc. The philosopher uses

his natural reason, particularly, human

reasoning.

Ethics

Aesthetics

Aesthetic

Epistemology

Logic

Metaphysics

Branches of Philosophy

Theodicy

Logic

From Classical Greek (logos),

means originally the word, or what is spoken,

(but comes to mean thought or reason). The

formal and systematic study of the principles of

valid inference and correct reasoning.

Ethics

The branch of philosophy dealing with the

concepts and principles of morality, including

such theoretical questions as the source and

foundation of morality, the status and

justification of moral rules, the relationship

between moral and other human objectives.

Epistemology

Epistemology (from Greek- episteme-,

"knowledge, science + logos) or theory of

knowledge.The branch of philosophy dealing

with the theory of knowledge-its source, limits,

kinds, and realibity. These central issues divide

major philosophical schools and label their

proponents as either empiricists rationalists

skeptics

Cosmology

The scientific study of the universe on the

larger scales on space and time, particularly the

propounding of theories concerning its origin,

nature, structure, and evolution

Metaphysics

A traditional branch of philosophy dealing

at the most general level with the nature of

existence-what it is, what sorts of things exist,

of what categories and in what structure. The

term originated form Aristotles first

philosophy, meta means physika which means

the after the physics

Aesthetics

Explores the nature of beauty, art, and

taste with the creation and appreciation of

beauty

Theodicy

The defense and vindication of God,

defined as both omnipotent and good in the

light of evil in the world. The term was first

used by Gottfriedm Wilhelm Leibniz (also

spelled Leibnitz) in 1710

Unit 2

UNDERSTANDING SOME

PHILOSOPHIES

Christian Philosopher

St. Thomas Aquinas

St. Augustine

St. Thomas AquinasA member of the Dominicans

Order, a scholastic philosopher and a theologian, St. Thomas Aquinas was born in 1225 at Castle Roccasecca, Aquino, Italy. His family was against his joining this fraternity of mendicant friars.

At first he studied with the Benedictines of

Monte Cassino, and later at the University of

Naples, and then with the Dominican

He died in 1274 and was canonizes in

1323. He is the best known for his two works:

Summa Contra Gentiles and Summa

Theologiae.

Happiness according to the philosophy of

St. Thomas Aquinas is not in the world, but in

union with God alone. Things found in this

world cannot make man perfectly happy

Greek philosopher

Socrates

Plato

Aristotle

St. Augustine

One of the most eminent doctors

of the Church, who became the Bishop

of Hippo, St. Augustine born on

November 13, 354 in Tagaste,

Numidia, now Souk-Ahras, Algeria.

His father was a pagan but later became a

Christian, and his mother Monica worked hard

for the conversion of her son to Catholic faith.

As a writer, he was prolific, brilliant,

persuasive and intelligent The Confessions is

considered one of his bet known works.

The Book depicted his early life and

conversion. In de Civitate Dei (The City of

God), St. Augustine formulated a theological

philosophical history. For St. Augustine, man

is created by God; hence, God is the supreme

God. For this Christian Philosopher, human

happiness can be found in God alone

Socrates

Socrates was born in

Athens in 469 BC. He is well

known today for his Socratic

Method, in which one asks for a

definition or concept and elicits contradictory

responses., finally demonstrating or exposing

the ignorance of the responder until the deeper

inquiry about the concept or definition is made

For him, knowledge is virtue, ignorance is

vice. Ignorance is the opposite of knowledge ,

and ignorance is evil so man commits evil

because he does not know any better

Plato

He was born in Athens to an

aristocratic family in 428 BC.

He travelled widely around 367 BC,

he found his academy in Athens.

The Republic is described as Platos

celebrated political utopia

The perfect man, according to Plato, does

not exist in this world because what we see in

this world is just an imperfect copy of mans

original self in the realm of ideas. The

individual thing that we perceive in this world

is not real, since they exist in space and time;

they change; and they pass in our existence

Aristotle

Aristotle, the Athenian student

of Plato, was born in 384 BC. He

returned to Macedonia an became

the adviser of Alexander, the son of

Phillip. Aristotle founded a famous school

named The Lyceum. It contributed much to the

development of Western science

According to him, if you do something

bad you feel unhappy. Such unhappiness is a

product of an act that is not guided by reason,

but by emotion. In order to be happy, the

philosopher said, one must act according to

reason.

Other philosopher

Confucius

Karl Marx

Confucius

From him comes the influential

Golden Rule. He was a Chinese

Philosopher born in the state of lu

(modern day Shandong Province )

and married at the early age of 19.

His ideas on social reform made him

popular and he became a model of the people.

But like everyone who has good and intelligent

ideas, Confucius also made some enemies with

his philosophizing that caused him leave the

state of Lu

Karl Marx

The German political

philosophical and revolutionary

co-founder with Friedrich Engels

of scientific socialism, Karl Marx is

one of the most influential contemporary

thinkers. He was born in Trier Germany on

May 5, 1818

And educated at the universities of Bonn,

Berlin and Jena

Marx was a follower of Hegel whose

philosophy centers on man. For Hegel, man

comes from matter. From the word springs the

name of his philosophy-dialect materialism.

Module 2

EXPLAINING THE NATURE

OF

LOGIC

The word logic is familiar to almost

everyone. Oftentimes, we hear person

undermine the credibility or authority of

another person by saying latters remarks or

statements are illogical.

On the other hand a person who makes

good, sensible statements relevant to the issue

being talked about is labeled Logical. The

description carries the condition of being

smart, clever and good in debate

Logic refers to correct thinking. Being

correct does not only mean that thinking has

sense. Logic is also concerned with the

arrangement of ideas, and ideas are logically

arranged If they appear in an clear and orderly

sequence

Unit 1

THE ESSENCE OF LOGIC

Logic

Derived from the Greek word logos

which means - study, reason or discourse

Logic is the format and systematic study

of thinking or reasoning. Logic is the science

and art of correct thinking

Format

Argument which is the building block of

logic is composed of two elements: matter and

form. Form is the structure of an argument.

Matter is its content. Formal refers to how

an argument of being formed or organized

Systematic

Logic is a science. It standardizes

knowledge of the principle governing correct

thinking. As a science, logic demonstrates the

law of correct thinking, how to develop correct

thinking, and how this thinking is to be

delivered to others by the use of symbols such

as words can either be written or spoken.

Correct Thinking

Argument is the expression of thinking

and thinking can be considered correct

depending on how an argument is being

formed.

Limits of Logic

Some students ask why logic is

integrated in the college curriculum.

Apparently, they do not see the practical

application of the subject in their lives.

Logic does not teach anyone how to reach

the moon or how to become rich. It can also be

said that a logician may not even know how to

protect or take care of himself from the rain.

Such practical things are beyond the range of

logic.

Importance of Logic

The person who has studied logic could

immediately spot the fallacy in another

persons argument. He can immediately form

an artistic reasoning.

Some benefits of studying logic include the

following :

Ability to think clearly, systematically andcritically

Self-confidence when arguing withsomebody

Capacity to correct wrong arguments and toavoid them

Dealing broad-minded, sensible, reasonable,and practical in dealing and establishing

relationships with people

Symbolic Logic

Conclusion, cause, and how the cause

brings out conclusion. Likewise, mathematics

is concerned with derivation. Mathematics is

Logic. All that involve arrangement, cause,

and effect are part of logic. To differentiate,

scholars call it symbolic logic

George Boole

He developed the mathematical

treatment of logic. Before

becoming a professor of

mathematics at Queens College, he

was a school teacher for a number of years.

One of his early works was the formulation of

algebraic theory.

His theory is known today as Boolean

algebra. Basically used to see abstract logic

functions, it connected Mathematics for the

first time formal logic. Boolean algebra is

very significant in the field of probability

statistics. Boole was a son of a self-employed

carpenter. With the meager income of his

family, he had little hope for a real education.

Boole was a son of a self-employed

carpenter. With the meager income of his

family, he had little hope for a real education,

He was trained to be a teacher , and learned

mathematics from his father. His favorite

subject was the Latin, Greek, German Italian

and French classics. He studied hard to write

mathematical text.

In 1849 he was awarded the Royal Societys

Medal for his work.

The Boolean algebra that now hears his

name was based on the principle forwarder by

Charles Babbage. Boole was influential in

formulating the principle of connection

between electrical circuitry and algebra. This

led to the invention of Babbages analytical

engine

Gottlob Frege

Gottlob Frege was born in

Wismar, Germany, and studied at

Jean and Gottingen. His book

Begriffsschrift (1879) explained his

system of symbolic logic. His other works that put him among the prominenet proponents of symbolic logic of include

Die Grundlagen der Arithmetic (The

Foundations of Arithmetic,1884) and

Grundgesetze der Arithmetick(The Basic Law

of Arithmetic 1893)

Kurt Godel

He had a life-long concern

about his health because he was

always ill. He studied mathematics

at the University of Vienna where he

received the degree of Doctor of

Philosophy in 1930. In his thesis, he proved ,

that first-order , every statement is provable

In his paper titled On Formally

Undecidable Propositions of Principia

Mathematicia and Related System, he

showed that if a formal system which is able

to describe simple arithmetic is consistent,

then it could not be complete. There are

propositions that can neither be proved nor

disproved on the basis of this system

Module 3

DIFFERENTIATING IDEA AND

TERM

Idea as a concept only exists in the mind.

Outside of your mind, nobody known what

your idea about a certain thing or issue is. If

you think, for instance, that a triangle is

composed of three sides, it is only in your

mind. Nobody knows that it is your idea of a

triangle. To be understood by others, you need

an instrument.

Unit 1

FORMING AN IDEA

Idea

Is the mental product of apprehension. It

is the mental/intellectual image or

representation of the object, because it

represents the object in the intellect or simply

a concept of image that exist in your mind.

Many philosophers have considered ideas to

be a fundamental on to logical category of

being.

Simple Apprehension

This is the mental act of perceiving an

object intellectually, without affirming or

denying anything concerning it. To apprehend

is to take hold of a thing as if with the hand; an

apprehension, as an act of the mind, is an

intellectual grasping of an object. Forming an

idea are involves the following.

Forming an idea are involves the following:

Attention

This is the activity of the mind in which it

focuses on something that is being percieve or

noticed.

Comparison

This happens when the mind notices the

similarities and differences of the

characteristics of the things being focused on.

Abstraction

The act of taking away or separating;

withdrawal

Characteristics of an Idea

An idea is a representation. The Merriam-

Webster Dictionary (1998) defines it is a

center meaning or purpose. Synonyms word

are concept, nation or impression. M, Pinon,

O.P. (1973) regard an idea is an intellectual

image image or representation of a thing.

Properties of an Idea

Comprehension

Is the set of thought elements or

conceptual features contained in an idea

including the attributes.

Is the sum total of the attributes or

thought - elements which constitute the idea

Extension

is the range or scope of individuals and

classes to which idea may be applied. It is also

referred to as denotation, application.

Is the sum total of all individuals, things

or beings or group to which the idea can be

applied

Examples

Comprehension Extension

Filipinos All naturalized & natural

born citizen of the

Philippines.

Male Filipinos Applies only to the male

citizens of this country.

Unit 2

CLASSIFYING TERMS

Term

Is exactly what idea is all about. It's

expressing your thoughts. The only difference

between the two is that an idea is in the mind

while term is outside of the mind.

Balsicas and Molano (1999)

Define term as a sensible arbitrary sign

which expresses an idea and the reality which

the idea represents in the mind

Timbreza (2000)

Explains term as the verbal expression of

an idea. It may be understood as an idea or

group of ideas expressed in words.

Pion(1973)

Maintains that terms express concepts as

sensible and conventional signs

Group of signs

Natural sign

Conventional sign

Accidental sign

Natural sign

These are natural entities that signify

something. Their meaning are not created by

man.

Conventional sign

These are man-made, physical entities.

Their signification are made by man.

Natural sign

These are natural entities that signify

something. Their meaning are not created by

man.

Conventional sign

These are man-made, physical entities.

Their signification are made by man.

Accidental sign

These are entities that symbolize

particular events that happened in the past.

Kinds of terms

I. According to Quantity

A. Singular

B. Particular

C. Universal

I. According to quantity

A. Singular

A term that stands for single., The signs

of singularity are:

1. Proper nouns:

Usually a nouns that spelled with capital

letters, example Philippines, TIP

2. Nouns modified by adjectives in the

superlative degree

Example:

The best reasoning

3. Demonstrative

Example:

That bag, This pen

4. Collective noun

Expressions of a single whole.

Examples

Audience- group of spectators

5. The articles

the, a, &an,

Example

The professors, The TIP campus on QC

B. Singular

A term that stands for an indefinite part of

an absolute extension or an explicit number

of a group.

1. Indefinite prononun and adjective

Some, few, several, both, most

Example: Some students are friendly

2. Numbers

Examples:

Five section

Fifth teen children

Sixty citizens

Eight trains

C. Universal

Term that applies to each of the members

of a class. The signs of universality are: All,

every, each, whosoever, whoever, whatever,

etc.

Examples

All the Filipino are hard working,

Everything I do, I do it for you

II. According to Incompatibility

1. Contrary

2. Contradictory

3. Privative

4. Correlative

II. According to incompatibility

1. Contrary

Term opposed to each other but their

oppositions allow possible classification

within the same class, they are terms in

extremeopposites.

Examples

rich & poor, intelligent & idiotic

2. Contradictory

A proposition so related to another that if

either of the two is true the other is false and if

either is false the other must be true

Example: Black- non-black.,

Living- non-living

3. Privative

Are opposite terms, one of which

signifies perfection but the other denies such

perfection. (e.g, Wealth- poverty, Health-

sickness,)

4. Correlative

Words that are separated in a sentence but

function together to perform a single function

Examples:

husband-wife, Teacher-student,

Father-son, Boy friend-girl friend

III. According to definiteness of meaning

1. Univocal

2. Equivocal

3. Analogous

III. According to definiteness of meaning

1. Univocal

A term that is usually applied in different

context but expresses the same meaning

Examples:

Man is a rational being

Juan is a man

2. Equivocal

A term with two or more meaning

Example:

Pitcher can be a container or the baseball

player who throws the ball to the batter.

3. Analogous

A kind of term whose meaning can be

partly the same and partly different in at least

two occurrence.

Example:

Healthy body, Healthy advice.

Unit 3

UNDERSTANDING

DEFINITION AND ITS

FEATURES

Definition

Definition and division involves the

process of developing correct and clear

thinking, Definition and division deal with

setting the function and meaning of a certain

term. They strip off term with it's vagueness

and provide it with clarity and distinctness that

make it different from other terms

Etymologically, the term defintion

originated from the Latin word definire

which means to "enclose" within certain

limit. Definition limits the meaning of the

word.

Two elements

Definien

Is the word or the term to be defined.

Definiendum

Is the statement or sentence that explain's

the meaning and function of the definien.

Example: "Man." (defenien) is a "rational

being." (definiendum)

Two kinds of definition.

1. Nominal Definition

2. Formal Definition

Nominal Definition

This explains the simple meaning or

function of a term

This explains the simple meaning or function

of a term. This does not include the thing

signified by the term. It is a definition by

naming the term which can be done in various

ways

A. Etymology

Defining the term by its own root word or

it's origin.

Examples:

Science comes from the Greek word scere

meaning "to know"

Sanguinity comes from the Spanish wordsangre meaning "blood"

B. Translition

Rendering a term or word from one languageto another.

Examples:

Lady - dalaga goodbye - aloha

Philos - love love - amor

Life - buhay kiss - halik

C. Synonyms

Giving another term with similar

meaning.

Example: deceased - dead significance

importance

D. Example

Explaining the meaning of a term by

giving an extended explanation or illustration

Example:

A school is an institution where people go to be

educated (e.g., "Technological Institute of the

Philippines.")

A movie is a story being acted and watched on the

screen (e.g., "The Godfather.")

Formal Definition

It gives the nature of the thing signified

by the term to be defined. It is composed of

genus or general characteristics and the

differentia, the difference of the term from the

other terms under the same group or family.

Term

The concept defined (e.g. "Man")

Genus

The family to which the term belong

(e.g. "an animal")

Differentia

The portion of the definition that is not

provided by the genus.

Module 4

MAKING PROPOSITION

AND

JUDGEMENT

Unit 1

UNDERSTANDING JUDGMENT

AND PROPOSITION

Judgment and Proposition

Judgment is accepting one idea and

rejecting the other. A judgment should

expressed in writing or speaking, it is called

proposition. As Ideas are expressed in the

concrete through the use of terms.

Elements of a Proposition

Subject

Predicate

Copula

1. Subject

Is the term or a group of terms being

talked about. It is either affirmed or denied.

2. Predicate

It is an action that affirms of denies the

subject.

3. Copula

It expresses the connection between

identity and terms

Examples:

Every Filipino (are) industrious.

subject copula predicate

Classification of Proposition

1. Quantity

Refers to the number of referents to which

the subject term is applied. It is either universal

or particular.

Examples:

All food are delicious. Universal

Some chairs are damaged. - Particular

2. Quality

Refers to the state of being, or it answers

the question what kind? It can be either

affirmative or negative

Examples:

Lagundi leaves is a good remedy for cough. -

Affirmative

Dogs are not cat. - Negative

Symbols of Propositions

1. A Universal affirmative

Example: All islands are stunning.

2. E Universal negative

Example: I am not a lawyer.

3. I Particular Affirmative

Example: Cats are pests

4. .O Particular negative

Example: Not all men are a saint.

Unit 2

OPPOSING LOGICAL

PROPOSITION

Opposition

It refers to the different relations that

exists between propositions having the same

subject & predicate, but different in quantity or

quality, or both.

Kinds of logical opposition

1. Contradictory

The propositions differ in both quantity

and quality.

Example:

All humans are mortal.

Some lawyers are boastful.

2. Contrary

Both differ in quality not in quantity.

(They are both universal.)

Example:

No soldiers are coward.

All Koreans are Asians.

3. Sub contrary

Propositions differ in quality but not in

quantity. (Both are particular)

Example:

Some politicians are honest.

Some politicians are not honest.

4. Subaltern

The propositions differ in quantity but not

in quality.

Example:

No engineers are egoist.

Some engineers are not egoist.

Laws of logical opposition

1. Contradictory propositions cannot be both

true & both false at the same time. If one is

true, the other is false and vice-versa.

Example:

if Some presidents are former movie actors.

is true, then No presidents are former movie

actorsisfalse

2. Contrary propositions cannot be both true

but they can be both false. If one is true,

the other is false but not vice-versa.

Example:

If All mass cults are kinetic art. is true, then

No mass cults are kinetic art. is false.

If All models are tall. is true then No

models are tall. is unknown or doubtful. (It

may be true; it may be false.)

3. Sub contrary propositions -the propositions

cannot be both false but they can be both

true. That is, if one is false, the other is true

but not vice-versa; that is, if one is true, the

other is unknown or doubtful. (It may be

true; it may be false)

4. Subaltern propositions

a. If the universal is true, the particular is

also true but not vice-versa.

B. If the particular is false, the universal is

also false but not vice-versa.

Unit 3

APPLYING LOGICAL

EQUIVALENCE

Logical Equivalence or Eduction

Is an inference in which the meaning of

the original proposition is made clear in the

second by the use and removal of negatives,

and by interchanging the position of the

subject and predicate of the original

proposition

Kinds of logical Equicalence

1. Conversion

2. Obversion

3. Contraposition

4. Inversion

1. Conversion

A form of eduction that involves

interchanging the position of the subject and

predicate terms. The original proposition in

conversion is called Convertend and the

inferred proposition is called Converse.

Rules of conversion

a) Interchange the subject and predicate.

b) Retain the quality of the proposition. (If

affirmative, it must remain affirmative; if

negative, it must remain negative.)

Kinds of Conversion

1. Simple conversion - the quality and

quantity of the converted are retained.

2. Partial conversion (conversion by

limitation) only the quality is retained

because the quantity is changed.

Example:

E and I propositions are converted by

simple conversion. A is converted only by

partial conversion. O propositions cannot be

converted

2. Obversion

A process of eduction that involves

changing affirmative propositions into

negative propositions.

The given propositions is called Obvertend

and the resulting proposition is called

Observe.

Rules of obversion

a) Retain the subject and its quantity.

b) Change the quality.

c) Put the contradictory or contrary of the

original predicate

3. Contraposition

Is a combination of obversion and

Conversion. It has an interchange of subject

and predicate. Like conversion. It presents

contradictories of terms like obversion

Two types of contraposition

1. Simple contraposition a given

proposition is obverted first and then

converted.

Rules of contraposition

a) Obvert the given.

b) Convert the obverse.

Note: I proposition cannot be contraposed

because if an I proposition is obverted, it

becomes an O proposition which cannot be

converted.

2. Complete contraposition

Rules of complete contraposition

a) Obvert the given.

b) Convert the obverse.

c) Obvert the converse.

Reminder: I proposition cannot be

contraposed simply or completely.

4. Inversion

Is another method of formulating a new

proposition called Inverse from a given

proposition called Invertend.

Two types of inversion

1. Simple inversion

2. Complete Inversion

Rules of simple inversion

a) Contradict the subject of the invertend.

b) Change the quantity of the invertend.

c) Change the quality of the copula.

d) Retain the original predicate.

Rules of complete inversion

a) Contradict the subject of the invertend.

b) Change the quantity of the invertend.

c) Retain the quality of the copula.

d) Change the predicate of the invertend to its

contradictions.

Reminder: I and O propositions have no

inverse.

Module 5

REASONING

Simple apprehension is the first act of the

mind. Judgment in which one idea is rejected

and the other accepted is the second act. Here,

the mind determines agreement and

disagreement of ideas.

Unit 1

VALIDATING THE TRUTH

Reasoning

This is an act in which from the known

truth or certainty, the mind travels to another

truth. It is a mental process that compares two

similar propositions; and out of these

propositions, a conclusion is drawn or formed..

It appears like the immortal format of

research that starts with some ideas the ideas

are analyzed, studied and observed; after

which, a conclusion made.

Kinds of Reasoning

Deductive

It is a reasoning process that forms a

conclusion out of a generally accepted fact

from general to universal to particular.

Inductive

It is kind of reasoning that forms a

conclusion from a particular to a universal or

general instance from particular to general.

Validating the Truth

In a reasoning mind is given the capacity

to form a new truth means that beforehand ,

there is already a known truth from which the

mind forms new one There must be two

propositions logically connected and closely

related in order to form a valid and sound

conclusion which is the new truth

Requirements that will enable one to form

Knowledge

1. The first two known truths which are

called premises should be both true

2. The first two known truths or premises

must have a logical and close connection

so that the third proposition,

the conclusion or the new truth is the necessaryconsequence of such logical relationship

Invalid Conclusion

If these two requirements are not strictlyobserved, then a conclusion which has been drawnout from premises is wrongly formed

Unit 2

FORMING A CATEGORICALSYLLOGISM

Categorical Syllogism

The Merriam-Webster Dictionary (1998)

defines syllogism as a logical science of a

formal argument consisting of a major premise

and a minor premise and a conclusion which

must be logically true

The preceding dictionary definition has

already covered all necessary elements of a

syllogism. In a similar vein ,categorical

syllogism is an argument that has tree

categorical propositions.

Categorical Term

Major

Minor

Middle terms

Furthermore ,the two premises areconsidered the antecedent or the cause and

the conclusion ,the consequent or result

Rules and Fallacies of Categorical Syllogism

The proposition in a series that forms a

syllogism may contain erroneous conclusion

emanating from the wrong premises. There are

rules to be followed and violation of them may

render the syllogism invalid

1. Fallacy of four terms

2. Fallacy of equivocation

3. Fallacy of misplaced middle term

4. Fallacy of undistributed middle term

5. Fallacy of negative premises

6. Fallacy of negative premises

7. The major and minor terms could not be

universal in the conclusion if they are not

particular in the premises. Violation of this

rule is called illicit process of the major if

the problematic term is distributed in the

conclusion but not in the major premise;

and an illicit minor if the problematic term

is distributed in the conclusion but not in

the minor premise.

Rules to be applied in order to determine the

extension or quantity of the terms in a

syllogism

1. If the proposition is negative , then its

predicate is universal.

2. If the proposition is affirmative , then its

predicate is particular.

3. If the proposition is particular ,then its

subject is particular

4. If the proposition is universal ,then its

subject is universal

Unit 3

UNDERSTANDING FIGURES OFCATEGORICAL SYLLOGISM

Figures Categorical Syllogism

Syllogism

Can be defined as a deductive argument

composed of two premises and one conclusion.

Categorical Syllogism

Is syllogism which consist of three

categorical proposition, as well as three terms

Term

a) Major term- predicate of the conclusion

and subject or predicate of the first premise

b) Minor term-subject of the conclusion and

subject or predicate of the second premise

c) Middle term-subject or predicate in each of

the premises and connects these two

premises together

Figure

Is the arrangement of terms (major,minor

and middle of the argument

1. FIGURE 1-The middle term is the subject

in the major premise and is the predicate in

the minor premise.

2. FIGURE 2-The middle term is the

predicate of both the major and minor

premises

3. FIGURE 3-The middle term is the subject

of both the major and minor premises

4. FIGURE 4-The middle term is the

predicate of the major premise and the

subject of the minor premise

4. FIGURE 4-The middle term is the

predicate of the major premise and the

subject of the minor premise

Unit 4

DISTINGUISHING HYPOTHETICALSYLLOGISM

Hypothetical Syllogism

The presence of a condition proposition in

the hypothetical syllogism makes it different

from the categorical syllogism.

Kinds of Hypothetical Syllogism

a. Conditional

b. Disjunctive

c. Conjunctive

Conditional Syllogism

This is an if and then statement is that

begins with if is the antecedent. The then

statement is the consequent.

Modus Ponens

The antecedent must be accepted in the

minor premise,as well as the consequent which

must be accepted in the conclusion

Modus Tollens

The consequent must be rejected in the

minor premise just like the antecedent that is

rejected in the conclusion. This means that the

falsity of the consequent implies falsity of the

antecedent

Important to Remember

The antecedent and consequent may be

both affirmative and both negative or one is

affirmative and the other is negative.when you

accept or affirm them, simply accept or affirm

the affirmative and negative as negative.

Modus Ponens

1. If A is B, then C is D.

A is B;

therefore, C is D.

2. If A is not B, then C is not D.

A is not B;

Therefore, C is not D.

3. If A is b then C is not D

C is not D

Therefore A is B

4. If A is not B, then C is D

A is not B

therefore, C is D

Modus Tollens

1. If A is B, then C is D

C is not D

Therefore, A is not D

2. If A is not B, then C is not D

C is D;

Therefore, A is B

3. If A is B, then C is not D

C is D;

Therefore, A is not B

4. If A is not B, then C is D

C is not D;

Therefore, A is B

Disjunctive Syllogism

This is an either-or syllogism. Its major

premise is a disjunctive proposition while the

minor premise and the conclusion are

categorical.

Rule of Disjunctive Proposition with Two

Components Parts

1. Affirm or posit one part in the minor

premise and deny or sublate the other part

in the conclusion.

2. Deny or sublate one part in the minor

premise and affirm or posit the other in the

conclusion.

In short, if the disjunctive proposition is strict,

just affirm one in the minor premise and deny

the other in the conclusion and vice-versa.

General Form Of The Strict Disjunctive

Syllogism

1. Proposition with two parts:

a. Either A or B.

It is A;

Therefore, not B.

b. Either A or B.

It is B;

Therefore, not A.

2. With more than two parts:

a. Either it is A, B or C.

It is A;

Therefore, it is neither B nor C.

b. Either it is A, B or C.

It is not A;

Therefore, it is either B or C.

NOTE:

If the disjunctive proposition is composed of

two parts, then one part must be denied in the

minor premise. The other part must be

affirmed in the conclusion.

Disjunctive proposition

Is composed of more than two parts. One

part must be negated in the minor premise and

the other must be affirmed with another

disjunctive in the conclusion.

Conjunctive Syllogism

Originates from the root word conjunct,

which means connected, united, joined or

combined.

Rule:

Affirm one of the disjuncts in the minor and

deny the other in the conclusion.

Module 6

AVOIDING FALLACY

Fallacy is avoided in discussions, debate,

and even in ordinary conversations. These

lessons on fallacy will equip students with

knowledge about the nature of fallacy so that

they can think smartly and avoid being

deceived

Fallacy is an argument that seems to be

correct but proves to be false. If it is committed

to deceive others, it is called sophism. If

committed without malice, it is called

paralogoism

Unit 1

UNDERSTANDING VERBALFALLACY

Verbal Fallacy

In his/her mind, a speaker thinks he/she

has a correct or accurate idea,but when he/she

articulates it , he/she makes a mistake.

Verbal fallacy is a mistake in the use of

words but not in the stucture of idea in the

mind of the speaker.

Verbal Fallacy includes the following:

1. Equivocation

This is a fallacy with the use of the same

word with different meanings in the same

argument.

Example:

A star is a heavenly body.

Katrina Halili is a star.

Therefore,Katrina Halili is a heavenly star

The word :star is equivocal; it has

everla meanings. The word star "in the first

proposition means the tiny things that sparkle

in the sky at night. The star in the second

line refers to the actors of celebrities. The two

meanings of the word star in this argument

resulted in a wrong conclusion

2. Amphiboly

It is ambiguous use of word or phrase

within a single and complete sentence.

Example;

He is a criminal lawyer

What is he? A lawyer who is a criminal? Or a

lawyer for Criminal case?

3. Accent

It is a fallacy or a mistake in the emphasis in speech or there is a mistake in the placement of the punctuation.

Example;

In the hignway, a signage says.SLOWMEN,AT WORK. The peron eho put up that announcement wants to warn motorists to slow down because there are men working.

Unfortunately, the comma was incorrectly

placed. The phrase now means slow or lazy

workers. The comma should have been placed

after the wordslow

4. Figure of speech

This fallacy happens when a person thinks

that a similarity of word would give the same

or similar meaning

Example:

Immaterial is not material

Insoluble is not soluble

What is inflammable is not flammable

The word inflammable has the same meaning

as the word flammable.

5. Composition

This is taking generally what is to be

taken individually. In order words, it is the

fallacy of generalization

Examples:

Ilocanos are tight-fisted

But, you are an ilocano

6. Division

It is the opposite of composition that takes

all things generally but needs to be taken

individually . In division, it is taking

individually what is to be taken generally.

Example:

Benigno Faral is a fraternity member

But, all fraternity members love hazing

Therefore, Benigno Faral loves hazing

Unit 2

UNDERSTANDING NON-VERBAL ORMATERIAL FALLACY

Non-Verbal Fallacy

Another word for non-verbal fallacy is

material fallacy or fallacy of matter. The

previous unit discussed verbal or formal

fallacy- the fallacy that is committed out of the

use of language. In short, the content of an

argument is fallacious or wrong.

Non-verbal or fallacy of matter inclueds the

following:

A. Ignoring the issue (Ignoratio elenchi)

Name calling or name dropping, character

assassination,attacking the person throush

his/her personal or physical defects are to be

avoided at all times.

The phrase used is at all times which means

that this fallacy must be strictly avoided.

There are other fallacious arguments under

this first kind

1. Argument against the person

2. Argument to people

3. Argument to sympathy

4. Argument to authority

1. Argument Against the Person

(Argumentun ad hominem)

It is an attack against ones personality,

instead of the topic being debated.

2. Argument to People (Argumentum ad

populum)

This happens when the speaker, for

instance in a debate , appeals to the peoples

prejudices, likes or dislikes instead of debating

the issue at hand. It appears like a

sensationalized argument.

.

3. Argument to Symphaty (Argumentum ad

misericordiam)

It is ignoring the issue when somebody

asks for sympahty instead of debating with

facts.

4. Authority or Dignity (Argumentum ad

verecundiam)

This happens when one justifies

something by name-dropping or citing the

names of people with authority and dignity.

5. Argument to Force(Argumentum ad

baculum)

It is an appeal to moral pressure a threat

until acceptance is assured.

.

6. Argument to Ignorance (Argumentum ad

ignorantiam)

It is an mistake done by ignoring the truth

of falsity of an issue and simply asserting its

truth or falsity because such an issue has never

been proven false or true.

.

B. Non-Sequitur

It is the Latin term for it does not

follow. This fallacy arises out of a hasty

conclusion. This means that connection

between the premises and conclusion is not

clear. In other words, there is no concrete

cause that leads to such a conclusion. There is

no connection between the cause and result.