Basic Formal Logic Flashcards
Truth
Statement describing reality
Validity
When the conclusion logically follows the premises
Sound
When an argument is both true and valid
Simple Apprehension
The act by which the mind grasps the concept or general meaning of an object without affirming or denying anything about it.
Term
The verbal expression of a simple apprehension, usually just one word; terms are divided into univocal, equivocal, and analogous.
The three stages of Simple Apprehension
Sense perception, mental image, concept through abstraction (simple apprehension)
Comprehension
The completely articulated sum of the intelligible aspects or elements (notes of Porphyrian Tree) represented by a concept.
Notes of the Porphyrian Tree
Substance (non-material existence)
Body (material existence)
Organism (living existence)
Animal (sentient existence)
Man (rational existence)
Extension
What the concept refers to; what tells us the things to which that essence applies.
i.e the term Man refers to all men that live, have lived, or ever will live. When the comprehension gets smaller, the extension extends to a larger group.
Significance of a term
Univocal, equivocal, analogous
Supposition of a term
Verbal (referring to the term as it exists in a grammatical form. i.e Man is a noun), Logical (when a term refers to something that exists logically. i.e Man has five notes), Real (when the term refers to the object as it exists in the real world. i.e Man was created by God)
Judgement
The act by which the intellect unites by affirming, or separates by denying. The second stage of reasoning.
Proposition
The verbal expression of Judgement, usually in the form of sentences. It expresses truth or falsity. In correct logical form, it requires a quantifier, subject, predicate, and copula.
A statement
All S is P. Affirmative and universal.
I statement
Some S is P. Affirmative and particular.
E statement
No S is P. Negative and universal.
O statement
Some S is not P. Negative and particular.
Quantifiers
All, some, no, some…not
Copula
Any form of the verb “to be”- am, is, are, was, were, etc.
Quality
When a proposition is affirmative or negative.
Quantity
Whether a proposition is universal or particular
Rule of Contradiction
Statements differing in both quality and quantity. A,O; E,I
Rule of Contraries
When universal statements differ in quality. A,E.