Introductory Notion of Judgment Introductory Notion of Judgment

The mind does not stop in the formation of ideas and terms.

It starts asserting relationship between these concepts, either affirming or denying it.

Examples:

“Juan is a Filipino”. Judgment

“Juan is not a Filipino”.

What is Judgment in Logic? What is Judgment in Logic?

• A mental act of affirming or denying the relationship between two concepts. A mental operation or act by which the mind affirms or denies anything whatsoever.

• Some people are generous

Man is a creature.

A dog is not rational.

A tree is not a cow.

Affirmation

Denial

Examples of JudgmentExamples of JudgmentEvery man is a rational animal.

No dog is human.

A tree is not a cow.

Baguio City is the summer capital of the Philippines.

Joseph “Erap” Estrada is the president of the Philippines.

Some people are generous.

Judgment and PropositionJudgment and Proposition

Theoretically, judgment is a mental act not yet verbally expressed. It exists only in the mind. But ideas need terms as a means of expression, so judgments need a tool for communication. This tool is called PROPOSITION. Therefore, every proposition is a judgment.

Prerequisites of JudgmentPrerequisites of Judgment

For a judgment to be valid and true certain prerequisites must be followed. They are the following:

1. The two related concepts must be thoroughly understood.

2. There must be an intellectual comparison between the two concepts/ terms. The mind must comprehend their identity or non-identity as basis for pronouncing a judgment.

• 3. There must be an objective perception of the relationship of the two concepts whether or not such relationship is of agreement or disagreement.

• 4. There must be a mental pronouncement of the agreement or disagreement of the terms compared.

Introductory Notion of PropositionIntroductory Notion of Proposition

A judgment is mental act not yet verbally expressed. But man has the faculty of speech and can put this in writing. So that if ideas need terms for expression, so judgment need a tool for communication.

This tool is called proposition.

A proposition is defined as a declarative sentence which expresses a relation of affirmation or denial between two terms.

It is a verbal expression of judgment.

Types of Proposition Types of Proposition There are two types of proposition: the Categorical and the Hypothetical. We shall discuss first the categorical. The Hypothetical will be discussed later.

1. CATEGORICAL PROPOSITIONS. A categorical is one in which the predicate term is either affirmed or denied of the subject term. If the predicate term is affirmed by the subject term the, the two terms are united and the proposition is called affirmative. If the two terms are denied of each other as indicated by the negative adverbs no or not, the proposition is called negative.

The subject and the predicate are united or separated by a copula, the present tense of the verb “to be”, am, is or are.

All pine trees are plants.

Some plants are not flowers.

All people are beautiful

I am a finite being.

The farmer is God’s servant.

No man is immortal.

Components of Categorical Proposition Components of Categorical Proposition

1. Subject Term

2. Predicate Term

3. Copula

Truth or Falsity Truth or Falsity • The mind’s act of affirming or negating a

relationship of terms in a proposition is in fact a declaration of truth or falsity. But how do we know a judgment is true or false?

It is the conformity between the mental judgment and objective reality. Or the congruence between what is in the mind and the objective world.

A tree is a plant.

The sun revolves around the earth.

Flowers are petals.

A triangle has four sides.

Igorots are Filipinos.

A dog is an irrational animal.

Reduction To Logical Form Reduction To Logical Form

• A proposition may run like this: “The dog barks. This has to be reduced to logical form – forming a categorical proposition by changing the verb into a linking verb in order to have a copula. Modify slightly or add a word without changing the thought of the original proposition.

ALL DOGS BARK. In logical form may be as follows:

All dogs are barking animals.

All dogs are barkers.

All dogs are animals that bark.

FILIPINOS WORK HARD. In logical form may be as follows:

Properties of Categorical Proposition Properties of Categorical Proposition

Quantity of Proposition

1. Universal Proposition

2. Particular Proposition

3. Singular Proposition

Quality of Proposition

1. Affirmative Proposition

2. Negative Proposition

Quantity and Quality CombinedQuantity and Quality Combined

• Reduction of Propositions to Four Basic TypesUNIVERSAL / SINGULAR AFFIRMATIVE A

UNIVERSAL / SINGULAR NEGATIVE E

PARTICULAR / AFFIRMNATIVE I

PARTICULAR / NEGATIVE O

INFERENCE:INFERENCE:

THETHE REASONING PROCESSREASONING PROCESS

Nature of Reasoning Nature of Reasoning Logic is the science of correct thinking. It starts Logic is the science of correct thinking. It starts

with ideas and terms and leads to the formation of with ideas and terms and leads to the formation of judgment and proposition. Using judgment and judgment and proposition. Using judgment and proposition it proceeds to the intellectual activity called proposition it proceeds to the intellectual activity called reasoning process or inference. reasoning process or inference.

Notion of InferenceNotion of Inference

the process in which from a sequence of propositions, we arrive at a conclusion. The mind proceeds from one proposition to other propositions.

Mental process of comparing 2 concepts with a common third term in order to establish agreement or disagreement with each other.

Inference consists of 2 parts: the antecedent and the consequent.

ANTECEDENT- CONSEQUENT RELATIONSHIPANTECEDENT- CONSEQUENT RELATIONSHIP

inference

Consequent (conclusion)

Antecedent (premises)

SEQUENCE

Example:Example:

Crimes are evil acts. Antecedent

But murder is a crime. Crime appears 2x.

Common 3rd term.

Sequential relation

Therefore, murder is an evil act. Consequent

There are three termsThere are three terms: :

• Crimes - appears twice in the premises. This term establishes a sequential relation between the 2 premises.

• Evil acts

• Murder

Kinds of InferenceKinds of Inference Immediate and Mediate Inference

Immediate Inference

A short-cut way of reasoning process passing directly from one proposition, without the aid of a second proposition or a third term, to a new proposition but not a new truth.

example: Crimes are evil acts.

Therefore, crimes are evil acts.

Kinds of Inference (cont.) Kinds of Inference (cont.) Mediate Inference

A process of reasoning whereby the mind passes from two propositions which are called premises to a new proposition called conclusion thru the mediation of of a common third term called the middle term. The mind arrives at a new truth.

This reasoning process or inference is called a syllogism.

The structure of a syllogism consists of 3 declarative sentences: 2 premises and one conclusion.

example: Crimes are evil acts. But murder is a crime. Therefore, murder is an evil act.

The Old CowboyThe Old Cowboy

You have lived to be 80 and know who you are...then along You have lived to be 80 and know who you are...then along

Comes someone and blows it all to hell........Comes someone and blows it all to hell........

An old cowboy sat down at the Starbucks And ordered a cup of coffee.

As he sat sipping his coffee, a young woman sat

Down next to him.

She turned to the cowboy and asked, 'Are you A real cowboy?'

He replied, 'Well, I've spent my whole life breaking Colts, working cows, going to rodeos, fixing fences, Pulling calves, bailing hay, doctoring calves, cleaning My barn, fixing flats, working on tractors, and feeding My dogs, so I guess I am a cowboy.'

She said, 'I'm a lesbian. I spend my whole day thinking About women. As soon as I get up in the morning, I Think about women. When I shower, I think about Women. When I watch TV, I think about women.

I even think about women when I eat. It seems That everything makes me think of women.'

The two sat sipping in silence.

A little while later, a man sat down on the other side Of the old cowboy and asked, 'Are you a real cowboy?'

He replied, 'Hell, I always thought I was, but I just found Out that I'm a lesbian'

TYPES OF REASONINGTYPES OF REASONING

DEDUCTIVE REASONING

and INDUCTIVE REASONING

DEDUCTIVE REASONING DEDUCTIVE REASONING - the mind proceeds from a universal - the mind proceeds from a universal

truth to a particular one. truth to a particular one.

Examples: 1. Every man is rational But the teacher is a man. Therefore, the teacher is rational. 2. A dog is an animal. But a person is not an animal. Therefore, a person is not a dog.

INDUCTIVE REASONINGINDUCTIVE REASONING- the mind proceeds to conclude from - the mind proceeds to conclude from

individual or particular cases to the individual or particular cases to the existence of a universal law or principle. existence of a universal law or principle.

Example:

Filipinos have 2 eyes each.

Americans have 2 eyes each.

Chinese have 2 eyes.

But Filipinos, Americans and Chinese are people.

Therefore, people have 2 eyes each.

THE CATEGORICAL SYLLOGISM THE CATEGORICAL SYLLOGISM

- a verbal expression of an inference. An oral or written discourse showing agreement or disagreement between 2 terms on the basis of a common third term.

- an argumentation from 2 propositions called premises, we arrive at a third proposition called conclusion.

- must always have a sequential relation in the presence of a middle term.

Observe the ff. propositions. Do they Observe the ff. propositions. Do they constitute a syllogism? Why? constitute a syllogism? Why?

Every man is a bipedBut every cow is a quadruped. Therefore, every cow is not a man.

All creatures are mortal. But a person is a creature. Therefore, a person is mortal.

COMPONENTS OF A CTEGROICAL SYLLOGISMCOMPONENTS OF A CTEGROICAL SYLLOGISM

Syllogism

Major Premise Minor Premise Conclusion

Major term (T), Minor term (t), Middle term (M)

Observe the following example:Observe the following example:

Every flower is a plant. (Major Premise)

But a fish is not a plant. (Minor Premise)

Therefore, a fish is not a flower. (Conclusion)

T – flower

t – fish

M – plant

The three (3) terms in the premises must be

UNIVOCAL.

A President is a ruler.

But a ruler is 12-inch thing.

:. A 12-inch thing is a President.

Therefore is represented by :.