Basic Terms in LogicBasic Terms in LogicMichael Jhon M. Tamayao

Learning ObjectivesLearning ObjectivesIdentify and define the basic terms in

Logic.Differentiate the terms according to their

use.Apply the terms in practical cases.

IntroductionIntroduction

Terms – basic elements that make up a language system.

The language of logic girds towards order.

What is LOGIC?What is LOGIC?“logos” = word, reason or

principleLogic – science of correct

reasoning.! Systematized! Evokes ORDER

What does Logic put into order?

1.) All men are mammalsAll students are men

:: All students are mammals.

2.) All monkeys eat bananaGeorge Lincoln eats banana

:: George Lincoln is a monkey

What logic puts in order is the way we reason out.

Logic makes explicit the rules of reasoning.

Inference – the process of deducing or extracting a statement (conclusion) from the previous statement/s.

Argument – the verbal expression of inference.

Syllogism – the format of arguments with three statements.

Conclusion – the statement being supported.Premises – the statement/s that support/s the

conclusion.

Key TermsKey Terms

ARGUMENT PREMISES

CONCLUSIONINFERENCE

SYLLOGISM

What is the importance of What is the importance of studying the Arguments?studying the Arguments?The answer:

It is the way we support our claims to truth and validity.

Truth and validity are the two aspects that measure the worth of an argument.

What is TRUTH in Logic?What is TRUTH in Logic?Truth – the correspondence or

equivalence of the mind to reality/object.

Statement Object

“The Horse is white”

The truth value of a statement is not proven by logicians but of empirical scientists, researchers and private detectives.

Logicians only study the reasoning found on statements and not the question of their truth values.

Judgment – the “act” by which the mind affirms or denies an attribute of a

subject. – The simplest act of the mind in

which it can attain truth.Proposition – “statement” that affirms or denies something.

– verbal expression of judgment

Simple Apprehension - more elementary “act” of the mind than judgment

– conceiving a notion of something.

“The Horse is white.” – verbally expressed as a

term/name.Terms – the two notions in a

proposition: subject and predicate

Acts of the Mind

Simple Apprehension

Judgment

Inference

Verbal Expression

Term/Name

Proposition

Argument/Syllogism

Propositions: Quality and Propositions: Quality and QuantityQuantity1. Quality – affirmative

negative Affirmative - predicate is affirmed

of the subject.ex. The audience is kind.

Negative - predicate is denied of the subject.

ex. The audience is not kind.

2. Quantity – universal or particular Universal – the predicate is

affirmed or denied of “the whole” subject.

Ex. “All” men are beings with heart.

“Not all” men are beings with heart.

Particular – the predicate is affirmed or denied of only “part of” the subject.

Ex. “Some” men are haughty. Some men not are haughty.

Four-fold Scheme of Four-fold Scheme of PropositionPropositionA-type: universal and affirmative

“All men are mortal”I-type: Particular and Affirmative

“Some men are philosophers”E-type: Universal and Negative

“Not all philosophers are rich.”O-type: Particular and Negative

“Some men are not rich.”

Terms also have “quantity” but not “quality”

Singular termsex. Socrates, Plato, Aristotle

Universal Terms ex. Men, horse

What is meant by What is meant by VALIDITY?VALIDITY?An argument is valid if the

premises do provide conclusive grounds for the conclusion. Otherwise, the argument is invalid.

Validity follows the different rules of inference.

Validity pertains to arguments/reasoning.

Truth pertains to propositions.

Logic has for its first principle the independence of truth and validity.

Independence of truth from Independence of truth from validityvalidityExample:

All men are animalsAll creatures are men::All creatures are

animals.

Although two statements are false, the argument is still valid.

FALSE

Key TermsKey Terms

TRUTH and VALIDITY simple

apprehension Judgment inference

“Sound” Argument – the reasoning in the argument is valid and all the statements are true.

Example:All computers are technological

productsAll abacuses are computers

:: All abacuses are technological products.

2 Kinds of Arguments2 Kinds of Arguments

1.) Deductive argument- An argument that has premises

which gives conclusive grounds for the truth of the conclusion, or if the premises claim to support the conclusion with necessity.- The process is exact.

e.g. All priests are humans.

All Popes are priests. :: All Popes are humans.

2.) Inductive Argument - Makes the wilder claim that

its premises support but do not guarantee the necessity of its conclusion.

- The conclusion is only given a high probability of correctness and “not” exactly valid or invalid.

Ex. Of all the 50 million swans I saw, nothing is black.

:: No swan is black.

Key TermsKey Terms

DEDUCTIVE INDUCTIVEExactValid or invalidNot a matter of

degree (All or Nothing)

ProbableStrong or weakA matter of

degree (More or Less)

What is a FALLACY?What is a FALLACY?Fallacy – bad method of argument,

whether deductive or inductive. – one or more of its premises

are false, or the reasoning from them may be invalid, or the language expressing them may be ambiguous or vague. – typical faults in arguments that sounds persuasive.

Ex. All Stars are hot.I am a Star.:: I am hot.

There is ambiguity in the meaning of the word star.

RecapRecapLogic – the science of correct reasoning.Inference – the process of deducing or

extracting a statement (conclusion) from the previous statement/s.

Argument – is a kind of reasoning/inference in which statements are offered to support or justify another statement.

Syllogism – the format of arguments with three statements.

Conclusion – the statement being supported.Premises – the statement/s that support/s the

conclusion.Truth – the correspondence or equivalence of

the mind to reality/object.Judgment – the “act” by which the mind

affirms or denies an attribute of a subject.

Propositions – verbal expression of judgments.

Simple Apprehension – conceiving of the notion of something.

Term – verbal expression of notions.Quality – may either be affirmative or

negative.Quantity – may either be universal or

particular.

Valid argument – an argument which has premises that provide conclusive grounds for its conclusion.

Sound Argument – an argument with valid reasoning and all its statements are true.

Deductive argument – an argument with premises that claim to support the conclusion with necessity.

Inductive Argument – argument with premises that support but do not guarantee the necessity of its conclusion.

Fallacy – a bad argument that has one or more false statements and/or invalid reasoning that sounds persuasive.

ENDThank you for

listening!