LOGIC IN GENERAL
TOPICS
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II.
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IV.
Definitions
Truth and Meaning
Material and Formal Objects of Logic
Ideas & Terms
LOGIC: Definitions
The science of correct reasoning
• As a Science: the Systematic Body of Knowledge of Reasoning
• Can be Verified/Validated, Replicated, & Accounted for
Man as Homo sapiens sapiens: Humans with Creativity & Imagination
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REASON: that which concerns itself to know things
INTELLECT: faculty that allows Reason to arise & flourish
Reason + Intellect = THINKING
Thinking + Analytical Perspective = CRITICAL THINKING
TWO TYPES
• Natural Logic: the innate natural order of correct thinking
• Biological Functions
• Scientific Logic: the systematic way of reasoning to examine thought
processes in difficult or controversial cases
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Debate
Theorizing
Philosophizing
Reflection
Contemplation
BRANCHES
FORMAL LOGIC
• Symbolic Logic, only concerned with the correctness rather than the
truth of a logical process
• Concerns itself with the FORM rather than the SUBSTANCE of the
argument
MATERIAL LOGIC
• Critical Thinking, concerned with the Truth, the substance of the
argument
• Establishes connection between thought-contents & reality to arrive
at the conclusion
3 DIVISIONS
I.
SIMPLE APPREHENSION: the intellect grasps the meaning of
something (passively taking hold of something without affirmation
or denial)
II. JUDGEMENT: the mental operation that pronounces the identity or
non-identity between ideas
III. REASONING: mental creation which proceeds from a previously
known truth to a new truth
IDEAS & TERMS
SIMPLE APPREHENSION
• Grasping and abstracting the essence/meaning of things without
denial or affirmation
• 2 Types of Meanings: Connotation(Symbolic) and Denotation(Literal)
• IDEA: mental product of apprehension
• TERM: verbal manifestation of an Idea
IDEAS
SENSE DATA  IMAGE  COMPREHENSION = IDEAS
SENSE DATA: experience through the senses
IMAGE: representation of the conscious experience; reflects the
sensible aspects of reality
COMPREHENSION: identifying the nature of the experience by
identifying the essential elements; divided into CONCRETE(that which is
perceived through the senses), and ABSTRACT(that which is universal in
scope of meaning)
IDEA: a mental sign to grasp the essence of something; considered as
abstract; CONCEPTS
TERMS
The need to communicate the Abstract
The importance of understanding the Abstract
TERM: the verbal manifestation of an Idea; a conventional sign that is
expressive of an idea
• SIGN: a recognizable connection between it and the entity/object to be
known; something that leads to the knowledge of something else
• CONVENTIONAL SIGN: an arbitrary sign which results from the ‘common
agreement’ among men; contra Natural Sign, where the connection with the
object that is represented is given by nature
• EXPRESSIVE of an idea: makes the abstract understandable via Language;
Terms serve to articulate Ideas
MEANINGS: The Logical Properties of Terms
CONNOTATION
• Indicates the meaning, the substance of something
• Aka intention, signification, or comprehension
DENOTATION
• Refers to something; the literal side of a term
• Relationship: Inversely-Proportional, as Connotation increases,
Denotation decreases, & vice versa
CLASSIFICATION OF TERMS
I. According to COMPREHENSION
II. According to EXTENSION
III. According to ORIGIN
IV. According to RELATION
V. According to MEANING
VI. According to QUALITY
VII. According to OBJECT
According to Comprehension
1. SIMPLE: expresses one conceptual note
• Truth: conformity between intellect and object
• Being: an existential thing
• Falsity: non-conformity between intellect and object
2. COMPOUND: expresses more than one conceptual note
• E.g. Man, God, etc.
3. CONCRETE: expresses something which has attributes that can be
perceived by the senses
• E.g. Ball, Desk, Table, etc.
4. ABSTRACT: expresses something that is separated from any single object;
a pure idea expressed in words
• E.g. Love, Perfection, Good, Evil, etc.
Note: A term or idea can be both Concrete & Abstract
According to EXTENSION
1. SINGULAR: represents one single object only.
• Proper Nouns: Names, Places, etc.
• Indicators: This dog, That face, My family
2. UNIVERSAL: represents not only a class as a whole but also each member of
the class
• Quantifiers: All, Everyone, Each, Nobody, Nothing, etc.
• E.g. Plants, Girl, Boy, Chair, Table
3. PARTICULAR: represents only a part of the Universal whether it is definite or
indefinite
• Not a whole; not referring to one, but refers to a part, or percentage
• E.g. Many(2 out of 10), Some(3 out of 10), Few, Several, Majority
4. COLLECTIVE: represents a number of things constituting a group or whole;
indicates a sum or aggregate and not as individual & unrelated units
• E.g. Family, Society, Choir, Humans, etc.
According to ORIGIN
1. IMMEDIATE: Intuitive, formed via direct perception of things
• E.g. whistle, chair, chirping, falling rain, doll
2. MEDIATE: Abstractive, formed via mediation of other ideas
• E.g. God, Life, Philosophy, Soul
According to RELATION
1. COMPATIBLE: terms that can co-exist in a subject
• E.g. wise and good, hot and spicy, rich and famous, young, wild, & free
2. INCOMPATIBLE: terms that cannot co-exist with one another; they
exclude each other
a)
b)
c)
d)
CONTRADICTORY
CONTRARY
PRIVATIVE
CORRELATIVE
INCOMPATIBLE TERMS
A. CONTRADICTORY: mutually excluding each other; no middle ground: one
affirms & the other denies
• E.g. Just –Unjust, Valid – Invalid, Legal - Illegal
B. CONTRARY: expresses extremes within the same class; there exists a middle
ground
• E.g. Rich – Poor, Beautiful – Ugly, Fast - Slow
C. PRIVATIVE: opposing ideas: one expresses perfection; the other the lack
thereof which ought to be possessed
• E.g. Truth – Lie, Good – Evil, Hearing – Deafness, Light – Dark
D. CORRELATIVE: opposing ideas with mutual correlation: one cannot be
understood without the other; each term is dependent upon each other
• E.g. Cause – Effect, Husband – Wife, Whole – Part
Note: An Idea or Term can be both Privative and Correlative
According to MEANING
1. UNIVOCAL: same meaning in several uses
• E.g. Animal, Polygon when predicated after an example stays the same
2. EQUIVOCAL: several meaning through several uses
a)
b)
Only in Pronunciation: dew – due, soar – sore, ill – eel
In Pronunciation & Spelling: Ground (Noun & Verb), Hunk (Noun & Adjective),
Trunk (Noun)
3. ANALOGOUS: meaning in some ways the same and in other ways
different
• E.g. God exists VS Man exists, Head of Family VS Head
*AMBIGUOUS: one term, several meanings
*VAGUE: no clear, distinct meaning; depends largely on context
According to QUALITY
1. Positive in Form, Positive in Meaning (+,+)
• E.g. Life, Justice, Truth, Freedom
2. Positive in Form, Negative in Meaning (+,-)
• E.g. Death, Lie, Error, Sin, Cruelty
3. Negative in Form, Negative in Meaning (-,-)
• E.g. Immoral, Illegal, Incompetent, Dishonest
4. Negative in Form, Positive in Meaning (-,+)
• E.g. Immortal, Infinite, Independent, Sinless
According to OBJECT
1. REAL: expresses something with existential qualities, whether
positive or negative
• E.g. Chair, Scandal, Enjoyment, Clarity
2. LOGICAL: used as a conceptual device to facilitate learning
• E.g. , Predicate, Phyla, Classification, Division
3. IMAGINARY: has no correspondence in reality but is merely a
fabrication of the mind
• E.g. Unicorn, Flying Carpet, Batman