Transcript Basic Terms in Logic - Law, Politics, and Philosophy

Basic Terms in Logic
Michael Jhon M. Tamayao
Learning Objectives
Identify and define the basic terms in
Logic.
 Differentiate the terms according to their
use.
 Apply the terms in practical cases.

Introduction
Terms – basic elements that make up a
language system.
 The language of logic girds towards order.

What is LOGIC?
“logos” = word, reason or principle
 Logic – science of correct reasoning.
! Systematized
! Evokes ORDER
 What does Logic put into order?

1.)
All men are mammals
All students are men
:: All students are mammals.
2.)
All monkeys eat banana
George 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 Terms

ARGUMENT
PREMISES
CONCLUSION
SYLLOGISM
INFERENCE
What is the importance of 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?

Truth – the correspondence or
equivalence of the mind to reality/object.
Statement
“The Horse is white”
Object
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
Verbal Expression
Simple Apprehension
Term/Name
Judgment
Proposition
Inference
Argument/Syllogism
Propositions: Quality and Quantity
1. 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 Proposition

A-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 terms
ex. Socrates, Plato, Aristotle
 Universal Terms
ex. Men, horse

What is meant by 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 validity

Example:
All men are animals
All creatures are men
::All creatures are animals.
FALSE
Although two statements are false, the
argument is still valid.
Key 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 products
All abacuses are computers
:: All abacuses are technological products.
2 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 Terms
DEDUCTIVE
INDUCTIVE
 Exact
 Probable
 Valid
 Strong
or invalid
 Not a matter of
degree
(All or Nothing)
or weak
 A matter of degree
(More or Less)
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.
Recap
Logic – 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.

END
Thank you for listening!