Logic

LOGIC

LOGICLogic comes from the word

“LOGOS”, which means “REASON”. It is concerned with the methods and rules for correct thinking.

LOGIC: The SCIENCE and ART of REASONING

•Logic, as an ART, on one hand, direct reason. As an ART it guides man’s reason so that he can proceed with order and precision in the search for meaning.

•Logic as a SCIENCE, on the other hand, “investigates, discovers, expresses, systematizes, demonstrates, and explains the laws of correct thinking.

METHODS OF REASONING

1.INDUCTIVE METHOD – where we can obtain universal knowledge by considering the particular things.

2.DEDUCTIVE KNOWLEDGE – when we proceed from universal knowledge to particular cases.

DIVISION OF LOGIC1. Material Logic – this focuses on the

study of the main philosophical problems taken up in logic such as problems of the universals, abstraction, or inductions.

2. Formal Logic – this is centered on the operation of the mind from the point of view of correct thinking.

Material Logic : Acts/Level of the Mind

• Simple Apprehension

• Judging

•Reasoning

SIMPLE APPREHENSION

It is the basic operation of the mind or “the mental process by which we grasp the general meaning of the thing without affirming or denying anything about it”.

JUDGINGIt is the act of the mind by

which we compare two, concepts, either they agree or not. If we put concepts together, the end result is called judgment or proposition.

REASONINGIs the act of mind by which we

derive new truths from previously assumed truth. The mind combines several judgments or propositions in order to arrive at a previously unknown judgment, it is called syllogism.

Levels of Expressions

• Term

•Proposition

•Inference

TERMA term is a word that

denotes a particular object. By denoting a term brings us an object or idea.

Types of TERM

• Simple and Complex

• Significant and Non-Significant

• Distributive and Collective

• Univocal, Equivocal and Analogical

• Contrary and Contradictory

Simple and Complex

• Simple – when the term used consists of a word, for instance “Jesus” such is called a simple term.

• Complex – composed of many term but standing one idea. Example, The lady in red walking down the street.

Significant and Non-Significant

• Significant – when a term is used to directly express a concept, it is called a significant term.

•Non-Significant – when it is not points directly to the nature of a thing.

Distributive and Collective

• Distributive – a term is distributive when it shows the essence of entities singularity.

• Collective – a term is collective when it shows the essence of entities as a group.

Univocal, Equivocal and Analogical

• Univocal – a term is said to be univocal when it has the same meaning.

• Equivocal – a term is said to be equivocal when it is used in entirely different sense.

• Analogical – a term is said to be analogical when it is used in distinct but related senses.

Contrary and Contradictory

• Contrary – terms are ones that represent two extremes of the same genus.

• Contradictory – terms are ones that are totally opposed to each other.

PROPOSITION

A Proposition is a sentence in which the subject and predicate are combined in order to state something as true or false. A Proposition therefore either affirms or denies.

The valid Propositional sentence excludes the Exclamatory, Interrogative, and the Imperative.

• Exclamatory Sentence – express emotions. Example: Give me liberty or give me death!

• Interrogative Sentence – ask questions. Example: Am I my brother’s keeper.

• Imperative Sentence – give orders. Example: Send this Order to the Mayor.

Parts of the Propositions

• Subject – is a bout which something is affirmed or denied.

• Predicate – is what affirmed or denied to the subject.

• Copula – is either is (am, are) if affirmative or is not (am not, are not) if negative.

Types of the Proposition

• Singular

• Particular

• Universality

Proper nouns Demonstrative Article “THE” Nouns modified by adjective in superlative degree Personal Pronoun

Singular (5 signs)

Particular (4 signs)

Indefinite Pronouns Article “A” and “AN”General Proposition Use of numbers

Universality (3 signs)

Universal idea Universal expression Article a, an, and the

Classification of Proposition

Positive

Negative

Universal or Singular

A E

Particular I O

The symbols A, E, I, O indicate the classification of categorical proposition on the basis of quantity and quality.

INFERENCE

Inference is a process by which the mind draws new knowledge or insight from any given proposition or a set of proposition. Inference must follow the valid sequence of premises.

Types of Inference

Immediate Inference – when there is no intermediary in deriving an opposite insight.

Mediate Inference – for instance the categorical syllogism, when there is an intermediary, i.e. . Middle term.

THE END

Prepared by : Ma.Luz T. Sisbreño