Wednesday, October 5, 2011

categorical syllogism

The Categorical Syllogism and Its Rules

Is the logical process in which, the premises relate two terms with a third (middle), and the relationship is expressed in the conclusion that either unites or separates the first two terms.

Major Term
Predicate of the Conclusion, found in the Major Premise (P)

Minor Term
Subject of the Conclusion, found in the Minor Premise (S)

Middle Term
Term found in both premises (m)

Major Premise (MP)
minor premise (mp)
Conclusion (C)

+ = affirmative proposition
- = negative proposition
u = universal
p = particular
s = singular

1. If the proposition is affirmative, then the quantity of the predicate is particular.
2. If the proposition is negative, then the quantity of the predicate is universal.

Rules of the Categorical Syllogism

1. The middle term must always be taken in the same sense.

A father is a male parent;
but, the Holy Pope is a father;
therefore, the Holy Pope is a male parent.

A tablet is a compressed solid material for writing;
but, Biogesic is a tablet;
therefore, biogesic is a compressed solid material for writing.

Fallacy of Equivocation

2. The major term and the minor term cannot have a greater extension in the conclusion than in the premise.

All hammers are tools;
But, no chisels are hammers;
Ergo, no chisels are tools.

All birds have wings;
But, all birds are animals;
Ergo, all animals have wings.

Fallacy of Illicit Minor Term
Fallacy of Illicit Major Term

3. The middle term should not occur in the conclusion.

A decagon is a polygon;
but, a decagon is ten-sided;
ergo, a decagon is a ten-sided polygon.

Fallacy of Misplaced Middle Term

4. The middle term must be distributed universally, at least once, in the premises.

All horses are fast-runners;
But, all rabbits are fast-runners;
Ergo, all rabbits are horses.

All mothers are females;
But, some females are barren
Ergo, some barren persons are mothers.

Fallacy of Undistributed Middle Term

5. Two affirmative premises cannot give a negative conclusion.

All writers have a rich imagination;
But, Dr. Rizal is a writer;
Ergo, Dr. Rizal does not have a rich imagination.

Fallacy of A Negative Conclusion drawn from Affirmative Premises

6. From two negative premises, nothing follows.

A chair is not a table;
but, a table is not a pen;
Ergo, a pen is not a chair.

Fallacy of Negative Premises

7. From two particular premises, nothing follows.

Some men are old;
Some old people are women
Some women are men.

Some cows are animals;
Some dogs are not cows
Some dogs are not animals.

Some delegates are not foreigners
Some Americans are delegates
Some Americans are not foreigners.

Fallacy of Particular Premises

8. The conclusion follows the weaker premise.

All roses are flowers
Some roses are fragrant
All fragrant things are flowers

All rebels are deviants
Some students are not deviants
Some students are rebels

Fallacy of Universal Conclusion drawn from a Particular Premise
Fallacy of Affirmative Conclusion drawn from a Negative Premise

judgment and proposition

Judgment and Proposition
 Ideas are not enough to give us a comprehensive knowledge of things because the human intellect cannot grasp in one apprehensive act all the perfections of a thing.
 The human mind has to proceed step by step, interrelating the ideas apprehended into judgment.
 The logical union of different ideas in a judgment reflects the real unity of things.
 Is a mental operation that pronounces the agreement or disagreement between two ideas.
 As ideas are expressed in the concrete through the use of terms, judgment is expressed in the concrete through the use of proposition.
 A proposition is a linguistic expression or the sensible sign of the judgment.
Constituents of a Proposition:
1. Subject – is the one spoken of, the one about whom or of which something is affirmed or denied.
2. Predicate – is what is affirmed or denied of the subject.
3. Copula – links the subject with the predicate.
4. The subject and predicate are called the matter because they are the materials or ingredients out of which the proposition is made.
5. The copula is the form for it is the unifying principle that gives the structure of a proposition.
Categorical Propositions
 Is that which gives a direct assertion of agreement or disagreement between the subject term and the predicate term.
The Standard-Form Categorical Proposition
 A standard-form categorical proposition contains four elements:
1. The quantifier
2. The subject term
3. The predicate term
4. The copula
 “All squatters are homeless.”
 Quantifier: All
 Subject : Squatters
 Copula: Are
 Predicate: Homeless
 The quantifier indicates the degree of universality (quantity) of the subject. A universal proposition is that which takes the subject in the entirety of its extension; a particular proposition limits this extension; and a singular proposition restricts it an individual subject.
 The Universal Quantifier. A universal quantification makes use of all, every, any, and other words of similar import for affirmative propositions; and words such as no, none, and other words parallel to these for negative propositions.
 “All books are reading materials.”
 The Particular Quantifier. A particular quantification makes use of words such as some, at least one, most, almost all, the majority, and other words of similar import for particular propositions. These particular quantifiers claim that at least one member of the class denominated by the subject term is a member (or non-member) of the class denominated by the predicate term.
 “Some students are scholars.”
 It means that at least one student is a scholar.
 The Copula. Is the linking verb is (am, are, was, were) and is not (am not, are not, was not, were not) indicating the agreement or disagreement between the subject term and the predicate term. The degree of agreement or disagreement is determined by the quantifier of the proposition.
Quality of the Categorical Proposition
 The quality of a proposition is the relation established between two terms of the proposition. If there is an agreement between the two terms, then the proposition is affirmative; if there is disagreement, then the proposition is negative.
 From the combination of quality and quantity, we derive four standard forms of categorical propositions. The vowels A, E, I, and O are used to represent each proposition. (AffIrmo – I affirm; nEgO – I negate)
 The subject term of universal proposition is always universal.
 The subject term of particular proposition is always particular.
Quantity of the Predicate Term
 The predicate of an affirmative proposition is always particular.
 The predicate of a negative proposition is always universal.

The Laws of Logical Opposition
 Laws of Contrariety
1. Contraries cannot be both true.
(If one is true, the other is false)
2. Contraries may be both false.
(If one is false, the other is doubtful, i.e. either true or false)
 Laws of Contradiction
1. Contradictories cannot be both true.
(If one is true, the other is false)
2. Contradictories cannot be both false.
(if one is false, the other is true)
 Laws of Subcontrariety
1. Subcontraries cannot be both false.
(If one is false, the other is true)
2. Subcontraries may be both true.
(If one is true, the other is doubtful, i.e., either true or false)
 Laws of Subalternation
1. What is true of the universal is true of the particular.
(If the universal is true, the particular is true)
2. (If the universal is false, the particular is doubtful)
3.What is denied of the particular is likewise denied of the universal.
(If the particular is false, the universal is false)
4. (If the particular is true, then the universal is doubtful)

Wednesday, August 17, 2011

informal fallacies

 Refers to errors of reasoning.
 Fallere – to deceive
 Formal Fallacy – committed mainly due to lack of skill in reasoning, and this in turn is due to lack of training in the logical process
 Informal Fallacy – committed when either irrelevant psychological factors are allowed to distort the reasoning process or when one is confused by linguistic ambiguities in one’s premises and conclusions.

A. Fallacy of Language

1. Equivocation
a. A king moves one square in any direction
But, Solomon is a king
Ergo, Solomon moves one square in any direction
b. Gambling should be legalized because it is something we can’t avoid. It is an integral part of human experience; people gamble every time they get in their cars or decide to get married.
c. “Boy” rhymes with “toy”
but you have a boy
ergo, you have a toy.

2. Amphiboly – awkward construction of one’s sentence allows a multiple interpretation.
a. To be repaired: the rocking chair of an old lady with two broken legs.
b. Wanted: A man to take care of a dog that does not smoke or drink.
c. Not seeing the patrol car, the car sped up.
d. Going up the stage, the crowd applauded the newly elected President.
e. If Croesus goes to war with Cyrus, he would destroy a mighty kingdom.

3. Fallacy of Accent
Arises from a false accent or from a false emphasis in speech.

A dessert is a course of fruit served after the meal. But, a desert is a forsaken region. Ergo, a forsaken region is a course of fruit served after meal.
Newspaper headline: “President to Declare Martial Law.”
The poster says: : Recycle clothes and waste paper.
3 day Sale – 75% off / FREE FAN

4. Fallacy of Composition
Consists in taking collectively what should be taken individually.

Since every part of a machine is light in weight, the machine as a whole is light is weight.
Manny Pacquiao is a boxer. He is a Filipino. Ergo, all Filipinos are boxers.
Since the cost for printing a book is relatively cheap, the book as a whole must also be relatively cheap.
One person can carry a wheel. That wheel is a part of my car. Therefore, one person can carry my car.

5. Fallacy of Division
Consists in taking individually what should be taken collectively

All diamond rings inside the jewelry box cost over 100 million pesos…
Everything in this room weighs about 1000 lbs…
A ballpen can write …
The family of Mr. Belen is very musical, Barry therefore, must be musically inclined.
La Sallians are handsome. Junn Aranate, a La Sallian, must be handsome.
An average Filipino family has 4 children. Tenirefe’s family is average. Therefore, she has 3 other siblings.

6. Fallacy of Word Construction
Infers a similarity of meaning from the similarity of the material pattern of the two words.

Infinite means without limit;
indefective means without defect;
ergo, indebted means without debt.
B. Fallacy of Relevance

1. Accident – what is true as a general rule is also true in some special cases. Also, when one confuses the substance with accidents.
All good soldiers should obey their superior’s orders…
We have to be generous…
One has to tell the truth always …
Principle of Confidentiality … (priest)

2. Petitio Principii (Begging the Question)
All criminals are immoral. Ergo, all criminals are not moral.
Why are you here? Because I’m not there!
We must not drink liquor. Why do you say that? Drinking is against the will of Allah. How do you know? The Koran says so. But how do you know that the Koran says right? Everything said in the Koran is right. How do you know that? Why, it’s all divinely inspired. But how do you know that? Why, the Koran itself declares that it is divinely inspired. But why believe that? You’ve got to believe the Koran, because everything in the Koran is right.

3. Argumentum ad Hominem (Attack against man)
You are very extravagant!
How about you? You have been extravagant yourself
You say I’m not pretty; Look who’s talking.
You should not listen to her opinion. She has been a drug-addict and has also been arrested due to theft.
Rasyl: Why were you late again in our class, Aubrey?
Aubrey: Look who’s talking. Last week you have been late twice, remember?
I saw and heard the candidate on TV last night. I shall not vote for him because he has lost his good looks.

4. Argumentum ad Populum (Appeal to People)
Our exams should be postponed, sir! The majority of the class have agreed to it.
“The war-mongering character of this flood of propaganda is very clear. But the shining reputation of our nation is impervious to slander, and we shall persevere.”
“It is beyond dispute that since Sanchez was implicated in the Sarmenta-Gomez case, the mass media have been regarding him as the most nefarious, notorious and abominable human being God ever created. How sure are we then that Judge Demetriou had not in the least been affected by the media pressures strengthened by the public’s outcry? ... I only want to remind the people that not all who have been convicted are really guilty; in the same manner that not all who have been acquitted are, in fact, innocent.” – from a reader of PDI Juliet Villar

5. Argumentum ad Misericordiam (Appeal to Pity)
A student should be given a passing grade because he is soon to graduate, or because if he fails his parents would kill him.
We cannot condemn this man because he is the only one that supports his family.
Where will the suspect’s poor wife get financial support for her family if you convict him? Where is your sense of justice, your sense of humanity? Where is your sense of compassion? How can you bear to see this poor man’s children suffer and eventually starve to death?
There was a youth who was tried for a particularly brutal crime – the murder of his mother and father with an axe. Confronted with an overwhelming proof of his guilt, he pleaded for leniency on the ground that he was an orphan.

6. False Cause
Say what you will! I’m not going to let a black cat cross my path. Noel let one cross his path and shortly thereafter his house caught on fire.
Frauline won lotto when she attended Mr. Belen’s class. Therefore, you should attend Mr. Belen’s class to win in the lotto.
He met an accident because it was Friday the 13th.
She sings in the kitchen; therefore, she will remain an unmarried woman all her life.
After he broke the bedroom mirror yesterday morning, he had a car accident that afternoon. Indeed, breaking a mirror is bad luck.
Ira received a text from a friend telling her to send it to 10 people and her love life will be happy. She said that last month she sent the text to 10 people and after a week her boyfriend became very intimate and caring to her. Ira should better send this text to 10 of her friends now.

7. Argumentum ad Verecundiam (Appeal to Misplaced Authority)
Aikken: These pills must be safe and effective for reducing.
Ritchel: What made you say that?
Aikken: My manicurist told me so.

Jose Javier Reyes, director of the movie “Live Show,” said in a press conference that MTRCB has unjustly banned the movie from being shown. According to Reyes, the movie is not pornographic since it has a very relevant plot and a well-written story line. Since Reyes is a veteran in Philippine cinema, we can say that indeed MTRCB acted wrongly in banning the said movie.

8. Argumentum ad Baculum (Appeal to Force)
“Agree with me or you’ll never get anything from me anymore.”
Demy to Sarah: “Be home by 9pm or you can forget about the increase in allowance next week.”
“Earl! You better agree to my proposal or you won’t see your family anymore.”
“Students! Keep quite! If not, all of you will fail in Logic!”

9. Appeal to Advantage
Rhegine offers Adrian, a government official, a huge amount provided he facilitate or give a favorable decision on some transactions in which Rhegine has some interest.
Allen Peter, a rich man, offers to pay the hospital bills of a beautiful young girl’s sick mother, provided the girl allows herself to be his mistress.
Gene, a religious political leader offers Inno a job, provided Inno joins Gene’s religion and accept his beliefs.

10. Argumentum ad Ignorantiam (Appeal to Ignorance)
Committed when one argues that something must be true on the basis that it has not been proven false, or false on the basis that it has not been proven true.

Kriss is a paragon of honesty because he has never been caught cheating by any of her teachers.
Faith healing must work; no one has ever been able to prove that it doesn't.
Gian believes that there are living creatures in Mars called Martians. Nobody can furnish evidence to disprove his contention, so it must be true.

Tuesday, April 12, 2011


The Nature of Philosophy

Philos - love

Sophia - wisdom


Lover of Pleasure

Lover of Success

Lover of Wisdom

Philosophy is a desire or interest for an intellectual inquiry

It is a discipline not to be defined but to be inquired into.

“Philosophy can’t be defined for it knows no limits just as the human mind knows no boundaries in its search for the rational explanation of reality and of man himself.”

Philosophy: A Discipline of Questioning

Anyone who asks questions is then philosophizing

A question is a conscious search for knowledge.

Authentic questioning:

1. It is for the knowledge of something.

2. It is an awareness of ignorance.

3. It is an awareness that there is more to be known.

As a discipline of questioning, it is:


It is an unending series of questions and answers.

“Questions are more important than the answers and every answer becomes a new question.”


“one man’s answer to a question may be valid for him but not for the next man.”

Philosophical concepts are not immutable doctrines

The Philosophical Method

Questions and answers are correlative.

In arriving at the correct and consistent answer to a question, the philosophical method of rational analysis and argumentation is needed.

Logic, as an art of correct thinking, must always be considered as a tool in facilitating this method.

Studying philosophy improves our reasoning skill. It is improved when it is critical, rigorous, systematic and objective or unbiased.

1. Critical means following the established scientific rules for correct reasoning.

2. Rigorous means avoiding inconsistencies and incoherence.

3. Systematic means observing certain order or procedure.

4. Objective means considering things from a disinterested point of view, honestly considering difficulties and problems, objections and alternative views.

The Major Divisions of Philosophy

Metaphysics - The study of reality or what is real.

Epistemology - The study of knowledge and what we can know.

Ethics - The study of the good.

Method of Philosophy

Philosophy accomplishes a knowledge of the world by means of human reason.

Theology treats God and the world on the basis of a supernatural revelation.

Object and Goal of Philosophy

Philosophy vs. Other Sciences

Other Sciences: also are particular sciences because they concern themselves with just a part of reality and look for the causes operative within the one restricted area of the real.

Philosophy: is the universal science because it considers the totality of reality and investigates the basic causes of all things; it propels toward the ultimate and absolute cause of being.

Logic: A Tool of Philosophy

Defined as the science of correct reasoning.

Science: a body of information concerning the different relations that arise in our mind when it knows things.

- The order that is reflected in our thought and actions is characteristic of the operation of the intellect when it knows the truth.

Man is naturally ordered to correct thinking (natural logic); but he has a special need of specific logic in order to examine his thought processes in difficult or controversial cases.

Logic is not the foundation of scientific knowledge; it is only its tools.

- It is incapable of giving a comprehensive criterion of validity.

- Merely facilitates in organizing ideas, express them with more accuracy and draw from them some legitimate conclusions.

Formal Logic and Material Logic

Arguments must be good not only in form but also in content.

Formal logic concerns itself primarily with the correctness rather than the truth of a logical process (following of the rules).

To be able to reason correctly is not necessarily the same as to reason truthfully.

Material Logic is concerned with truth of the material content.

It considers the correspondence of the thought-contents with reality, a correspondence between the logical and real order.

Division of Logic

Three Basic Operations of Human Thought:

Simple Apprehension is the act by which the intellect grasps the essence of something (apprehension because it lays hold of the thing mentally; simple because the intellect merely takes the thing in without any affirmation or denial about it.)

Judgment is a mental operation that pronounces the identity or non-identity between two ideas.

Reasoning is a mental act that proceeds from the previously known truth to a new truth.

Logic: The Art of Reasoning

Not only is Logic a science; it is also an art.

Art is the power to perform certain actions guided by special knowledge and executed with skill.

Critical Thinking

In college, students are challenged to question, examine and evaluate ideas and information

It is not merely absorbing information and acquiring knowledge

Students are expected to carefully and personally understand what they see, hear and read

Goal of education – teach students not only what to think but how to think – that is, how to effectively deal with problems, analyze issues and make decisions

The word “critical” often carries a negative connotation, implying excessive fault-finding.

It means that it is focused on exercising objective, fair and skilled judgment and analysis of ideas, beliefs and arguments.

Critical thinking is a general term given to a wide range of cognitive skills needed to effectively interpret, analyze and evaluate arguments and truth claims, to formulate logical arguments and to make reasonable, valid and sound decisions.

In short, it means to think clearly, logically and intelligently.

Interpretive skills
determine its precise meaning, what it actually claims. (simple apprehension)

Verification skills
determine whether statements are true or false. (judgment)

Reasoning skills
determine whether or not the what it claims has adequate support or basis for it to be accepted. (Reasoning/Inference)

Characteristics of a Critical Thinker

Critical Thinkers

honest, acknowledge what they don’t know, recognize their limitations and being watchful of their own errors

Base judgments on evidence rather than personal preferences, deferring judgment whenever evidence is insufficient

Interested in other’s ideas, willing to read and listen attentively

Practice restraint, control of feelings and not controlled by them, thinking before acting.

Think independently, not afraid to disagree with group opinion

Uncritical Thinkers

Pretend they know more than they do, ignore their limitations, and assume their views are error-free.

Base judgments on first impressions and gut reactions, unconcerned about the amount or quality of evidence

Preoccupied with self and own opinions, unwilling to read/listen

Tend to follow their feelings and act impulsively, acting before thinking

Tend to engage in “group think,” uncritically following the beliefs and values of the crowd

Value of Critical Thinking

Concerns not only about what we believe but about why we believe it. (higher-order thinking: active, intelligent evaluation of ideas and information) Understand and critically evaluate the materials used in college

Helps us avoid making foolish personal decisions

Citizen’s decisions be as informed, deliberate and reasonable as possible since the future of our country depends heavily on the kinds of choices and decisions we make. (serious societal problems: environmental destruction, political and economic instability, declining educational standards)

Mastering critical thinking skills is a matter of self-respect. Most people, most of the time believe what they are told. It diminishes us as persons if we let others do our thinking for us. We will remain slaves to the ideas and values of others and to our own ignorance. This can help to free us from the unexamined assumptions, beliefs and prejudices of our upbringing and our society.

Identifying Arguments

All morality is a form of social control. All law is codified form of social control. Therefore, all law is a codified morality.

Logicians call this kind of reasoning an ARGUMENT. In this case, the argument consists of three statements:

1. All morality is a form of social control.
2. All law is codified form of social control.
3. Therefore, all law is codified morality.

Statements 1 and 2 give reasons for accepting the statement. In logic, they are called the PREMISES of the argument, and statement 3 is the CONCLUSION of the argument.

Thus, an ARGUMENT is a series of statements one of which is the CONCLUSION (the thing argued for) and the others are known as the PREMISES (reasons for accepting the conclusion). It is also an attempt to show that a claim is true (conclusion) by providing reasons for it (premises).

Not all groups of statements make an argument. The sentences in an argument must express statements (i.e. they must state something that is either true or false.) Otherwise, they are non-arguments.


This 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 TRUE and the conclusion FALSE. In such arguments the conclusion is claimed to follow NECESSARILY from the premises.

DEDUCTIVE ARGUMENTS are those that involve necessary and certain reasoning.

Examples: A dog is a member of the canine family. All members of the canine family are carnivores. Therefore, a dog is a carnivore.

If M is equal to N, and N is equal to P. therefore, M is equal to P.

Kinds of Deductive Arguments

1. Arguments based on Mathematics

Depends on some purely arithmetical, geometrical or algebraic computation or measurement

Eg. A square piece of land measures 100 meters on each side. What is the total land area?

2. Arguments based on Definition

The conclusion is claimed to depend merely upon the definition of some words or phrases used in the premise or conclusion.

Eg. John is virtuous person because he has good moral quality.

3. Categorical Syllogism

Each statement begins with a logical quantifier.

Eg. All life forms need water to for food processing. Plants are a kind of life form. Therefore, plants need water for food processing.

4. Hypothetical Syllogism

A kind of deductive argument having a conditional statement for one or both of its premises.

e.g. If Darwin’s theory of evolution is correct then we will find fossils which shows sequential changes throughout the ages. But, evidence shows otherwise. Therefore, Darwin’s theory of evolution either needs revision or must be abandoned as unsupported by evidence.

5. Disjunctive Syllogism

A kind of deductive argument having a disjunctive statement (either/or statement) for one of its premises.

e.g. Either we study our lessons or we see a movie. We study our lessons. Therefore, we will not see a movie.


An argument is inductive if the content of its conclusion extends beyond the context of its premises. It claims that its premises give only some degree of PROBABILITY (expectation, prediction, likelihood, chance, tendency) but never certainty, to its conclusions.

The weakness of induction results mainly from our failure to realize that it only gives PROBABLE KNOWLEDGE AND NEVER CERTAIN KNOWLEDGE.

“I have seen only six cats, and they were all blue. I must conclude, tentatively, that all cats must be blue.”

All it takes in this case is the observation of one yellow cat to give a fatal blow to a viable hypothesis. Inductive conclusions are always subject to change.

If one should witness three car accidents in the period of an afternoon, all involving the same brand and model of a car, most of us would be tempted to conclude that something is wrong with this particular brand and model of car.

This conclusion would be an inductive hypothesis with apparent validity. But it is NOT A CERTAIN CONCLUSION; it is only a possible and probable explanation. Add ten more involving the same brand and model of the car, is one more certain of the validity of our hypothesis?

Yes, but only more certain, never absolute. Now what happens when you discover that all the drivers were driving on the wrong side of the road?

Kinds of Inductive Arguments

These various kinds of inductive arguments are not always mutually exclusive. Overlaps can and do occur.

1. Predictions

In a prediction, the premises deal with some known event in the present or past, and the conclusion moves beyond this event to some event in the near future. Since future events cannot be known with certainty, thus, we can consider predictions as inductive in nature.

e.g The prices of gasoline and other petroleum products increase during the winter season. Thus, this month of December we can expect another round of price increase.

2. Arguments based on Analogy

This is an argument that is based on the existence of an analogy or similarity between things, events or state of affairs.

A and B have characteristic X.
A has characteristic Y.
Therefore, B has characteristic Y.

e.g. Togo sardines was made by the same company that made 888 sardines. 888 sardines are very tasty. Therefore, Togo sardines must also be tasty.

3. Arguments based on Signs

This is an argument that proceeds from knowledge of the meaning of a certain sign to a knowledge of another thing, event or situation that the sign symbolizes. A sign might be misplaced or misinterpreted, thus the conclusion is only probable.

Natural Sign
Conventional Sign
Formal Sign

4. Argument based on Authority

This kind of inductive argument rests its conclusion upon a statement by a presumed authority or witness. Such arguments are essentially probable because an authority or witness could either be mistaken or simply lying.

e.g. The Law of Universal Goodness and Love must be indeed true and universally valid. It was first proposed by the great mathematical physicist who is a friend of the current Pucasian Professor of Mathematics at Hambridge University.

5. Inductive Generalizations

An argument that proceeds from the knowledge of a selected sample to some general claim about the whole group.

Z percent of observed F’s are G.
It is probable, therefore, that Z percent of all F’s are G.

e.g. I tasted some sweet fruits from a whole kaing of iba fruit. I think the whole batch must be sweet.

6. Causal Inference

They underlie arguments that proceed from knowledge of a cause to knowledge of the effect, or conversely, from knowledge of an effect to knowledge of a cause. Because specific knowledge of cause and effect can never be known with absolute certainty, one may interpret causal inferences as inductive arguments.

Examples: This can of softdrink was frozen hard. It must have been left accidentally in the freezer over night. (EFFECT TO CAUSE)

This can of softdrink was accidentally left overnight in the freezer, thus it must have been frozen hard. (CAUSE TO EFFECT)

Deductive arguments claim that

If the premises are true, then the conclusion is certainly true.
The conclusion follows necessarily from the premises.
The premises provide conclusive evidence for the truth of the conclusion
The truth of the premises guarantees the truth of the conclusion.

Inductive arguments claim that

If the premises are true, then the conclusion is probably true.
The conclusion follows probably from the premises.
The premises provide good (but not conclusive) evidence for the truth of the conclusion
The truth of the premises makes the truth of the conclusion likely.

Deductive indicator words :

It is logical to conclude that
This logically implies that
This entails that
It must be the case that

Inductive indicator words :

Chances are
One would expect that
It is plausible to support that
It is reasonable to assume that

Understanding the Problems of Language
 Thinking and reasoning are mental processes. (they happen inside the mind)
 Is it possible for others to read our mind?
 How then can we communicate to others what’s going on in our mind?
 (answer: use of LANGUAGE – most effective means through which we can express our thinking and reasoning.)
 However, the relationship between thought and language is not that simple.
 It can be a source of miscommunication and misunderstanding between people.
 A term is vague when it lacks a clear or precise meaning.
 A term is ambiguous when it has more than one meaning.
 Refers to lack of clarity in meaning.
 Meaning has no exact boundaries.
 Example: If a buyer tells a real estate agent: We need a big house.
 How BIG is BIG? Does she mean a bungalow or a mansion? How many bedrooms should there be?
 In order to remove the vagueness of language, we may use a more specific term.
 Arises when a term or a sentence has more than one meaning.
 “Pen”
 “Lie”
 A word is ambiguous when it is not obvious which of its meanings is intended in a situation in which the word is used.
 Semantic Ambiguity – results from uncertainty about the meaning of a particular word or phrase in the sentence.
 Grammatical Ambiguity – sentences can be interpreted with more than one meaning due to the way words are put together. (faulty grammatical construction)
 “My friend saw a bat at the corner of the room.”
 “Congressman Perez spoke against gender discrimination in the House of Representatives.”
Verbal Disputes
 Disagreement over certain issue because of different notions of what the term means; or which arises from linguistic problems (such as vagueness and ambiguity)
 Q: “Did the Philippines achieve economic progress during Arroyo’s administration?”
 Person A: “YES!” – thinking that the GNP improved significantly from the time Arroyo assumed presidency.
 Person B: “NO!” – thinking that the rate of unemployment did not grow down but to continue to rise.
 They disagree with each other due to the simple fact that they understand the term economic progress in different ways.
 How to avoid?
 Clarify from the very beginning what the words in the sentence actually mean.
 “What do you mean by that?”
 “In what sense are you using the word?”
Genuine Disputes
 Arises NOT because people have different understanding of the terms but because people have DIFFERENT knowledge, information or belief about something.
 Person A: “The Philippines achieved economic progress because there are less unemployed in the country compared before.”
 Person B: “The Philippines did not achieve economic progress because the rate of unemployment now is higher than before.”