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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!