lec 3 Terms

Overview

• Lecture 3 introduces basic classical logic focused on terms (this week).
• Course plan: today — terms; next — propositions; then — syllogisms; final logic week — fallacies.
• Logic studies how the mind forms concepts, makes judgments, and reasons validly.

Key Concepts: Three Acts Of The Intellect

• Simple Apprehension (First Act): form simple concepts/universal ideas via abstraction (e.g., "mammal", "human").
• Judgment (Second Act): join or separate two concepts to form propositions (e.g., "All humans are mammals"; "No mammals are reptiles").
• Reasoning (Third Act): combine propositions to draw conclusions (syllogisms; e.g., premises → conclusion).

What Is A Term

• Definition: a concept communicated through a symbol (word, sign, writing).
• Distinction: concept = idea in the mind; term = concept in communication.
• Terms function as symbols representing the meaning/form of words in logical contexts.

Types Of Terms (By Reference)

• Empirical (individual) term: denotes a particular or aggregate; uses proper names or descriptions (e.g., "Christopher Columbus", "the desk in this room").
• General (universal) term: signifies essence of a genus or species; uses common names (e.g., "tree", "human").

Concrete vs Abstract Terms

• Concrete term: represents realities as they appear (e.g., "animal", "near", "warm").
• Abstract term: represents substance or accident mentally abstracted (e.g., "animality", "humanity").

Absolute vs Relative Terms

• Absolute term: understandable alone without reference (e.g., "man", "tree", "red").
• Relative term: meaningful only in reference to another term (e.g., "husband" ↔ "wife"; "parent" ↔ "child"; "teacher" ↔ "student").

Collective vs Distributive Use

• Collective: group treated as single unit; verb/pronouns singular (e.g., "The audience shows its pleasure").
• Distributive: members considered individually; verb/pronouns plural (e.g., "The audience tossed their hats").

Types Of Difference Between Terms/Things

• Categorical difference: different categories (e.g., substance vs quality).
• Generic (generic) difference: different genera within same category (different kinds of the same category).
• Specific difference: different species within same genus (e.g., red vs blue as specific colors).
• Individual difference: distinct individuals within same species (e.g., this woman vs that woman).

Opposition / Repugnance (Contraries vs Contradictories)

• Repugnant/Opposite: terms that cannot coexist in same subject at same time.
• Individual and specific differences often repugnant.
• Contrary: two opposed terms within same genus but not exhaustive (e.g., "blue" and "red").
• Contradictory: exhaustive opposites covering all cases (e.g., "blue" vs "non-blue"; "mortal" vs "immortal"). Prefer contradictories for definitions.

Extension vs Intension (Intention)

• Extension: total set of objects to which a term applies (e.g., extension of "human being" ≈ world population).
• Intension (intention): meaning or sum of essential characteristics (definition) of the term (e.g., "human being" = "rational animal").
• Inverse relation: increasing intension (more specific definition) decreases extension (fewer objects); decreasing intension increases extension.

Pory's Tree (Classification Tool)

• Pory (Porphyry) proposed a branching "tree" to classify beings for definition.
• Uses contradictory oppositions at branches to avoid leaving out possibilities (e.g., substance → material / immaterial).
• Example path (material substances): body → animate/inanimate → organism → sentient/non-sentient → animal → rational/non-rational → man (rational animal).
• Purpose: help form genus + differentia for species definitions.

Definitions And Predicables

• Five predicables: Genus, Species, Differentia (specific difference), Property, Accident.
  • Genus: broad class (e.g., "animal").
  • Species: natural kind (e.g., "human").
  • Differentia: essential feature distinguishing species within genus (e.g., "rational" in "rational animal").
  • Property: flows from essence but is not part of it; present universally in species.
  • Accident: contingent predicate not essential and shared by many species.

Logical (Real) Definition vs Distinctive Definition

• Logical (real) definition: species = proximate genus + specific differentia (ideal form).
  • Example: human = animal (genus) + rational (differentia) → "rational animal".
• Distinctive definition: species = genus + one or more properties (used when a single differentia is unavailable).
  • Example: define an animal species by a cluster of distinctive properties instead of one differentia.

Other Types Of Definitions

• Causal definition: defines by one of four causes (material, formal, efficient, final).
  • Material: what a thing is made of.
  • Formal: the form or essence (often species).
  • Efficient: agent that produces it.
  • Final: purpose or end.
• Descriptive definition: lists observable characteristics to recognize the species.
• Nominal definitions: define the word rather than the thing.
  • Etymological: roots and origin of the word.
  • Synonymous: using synonyms (dictionary style).
  • Arbitrary: convenient stipulations for a discussion (use with caution).

Five Attributes Of A Good Definition

• Convertible with the subject: definition and defined term substitute for each other.
• Positive (avoid negative definitions).
• Clear (avoid vagueness).
• Free from words derived from same root (avoid circularity).
• Parallel grammatical structure: use same grammatical form for term and definition (e.g., noun defined by noun).

Practical Notes / Instructor Emphasis

• Definitions matter: inability to define a term indicates lack of clear understanding.
• Dictionaries (synonym-based) are useful but insufficient for philosophical definitions.
• Expect more practical use of terms in categorical syllogisms (upcoming class five).
• Next class: propositions (joining terms into judgments); reading: Plato's Meno.