Traditional Logic I Vocabulary ⋆.˚🦋༘⋆

The Logic course for Challenge I in CC. Happy practicing!

Logic

the science of right thinking

Formal (Minor) Logic

interested in the form or structure of reasoning - concerned with the method of deriving one truth from another

Material (Major) Logic

concerned with the content of argumentation - deals with the truth of terms and the propositions in an argument

Soundness

both truth and validity

Valid

the conclusion follows logically from the premises

Truth

the correspondence of a statement to reality

Mental Act: Simple Apprehension

verbal expression: term

Mental Act: Judgement

verbal expression: proposition

Deductive Inference

making logical connections between the terms in an argument that shows us that the conclusion either follows or does not follow the premises

Mental Act: Deductive Inference

verbal expression: syllogism

Judgement

the act by which the intellect unites by affirming, or separates by denying

Proposition

a sentence or statement which expresses truth or falsity

Comprehension

the complete sum of the notes represented by that concept

Extension

the sum of real things to which the concept refers

Univocal Terms

have exactly the same meaning no matter when or how they are used

Equivocal Terms

terms that, although spelled and pronounced exactly alike, have entirely different and unrelated meanings

Analogous Terms

terms that are applied to different things but have related meanings

Material Supposition

when a term refers to something as it exists verbally

Logical Supposition

when a term refers to something as it exists logically

Real Supposition

when a term refers to something as it exists in the real world

Logical Form

the form a statement must have in order to be handled logically

Quality

affirmative or negative

Quantity

universal or particular

Rule of Contradiction

contradictory statements are statements that differ in both quality and quantity (A and O, E and I)

First Law of Opposition

contradictories cannot at the same time be true nor at the same time be false

Rule of Contraries

two statements are contrary to one another if they are both universals but differ in quality (A and E)

Second Law of Opposition

contraries cannot at the same time both be true, but can at the same time both be false

Rule of Subcontraries

two statements are subcontrary if they are both particular statements that differ in quality (I and O)

Third Law of Opposition

subcontraries may at the same time both be true, but cannot at the same time both be false

Rule of Subalterns

two statements are subalternate if they have the same quality but differ in quantity

Fourth Law of Opposition

subalterns may both be true or both be false - if the particular is false the universal is false; if the universal is true, then the particular is true; otherwise, their status is indeterminate

Distribution

the status of a term in regard to its extension

Rule for Distribution of the Subject-Term

the subject-term is distributed in statements whose quantity is universal and undistributed in statements whose quantity is particular

Rule for Distribution of the Predicate-Term

in affirmative propositions, the predicate-term is undistributed (particular) and in negative propositions, the predicate term is distributed (universal)

Obversion

1. Change the quality of the sentence

2. Negate the predicate

Conversion

1. Switch the subject and predicate

Contraposition

1. Obvert the statement

2. Convert the statement

3. Obvert the statement again

Reasoning

the act by which the mind acquires new knowledge by means of what it already knows

Antecedent

the first and second premises of a syllogism

Consequent

the conclusion of a syllogism

Syllogism

a group of propositions in orderly sequence, one of which (the consequent) is said to be necessarily inferred from the others (the antecedent)

Essential Law of Argumentation

if the antecedent is true, the consequent must also be true

Major Term

predicate of the conclusion

Minor Term

subject of the conclusion

Middle Term

appears in both premises but not in the conclusion

Major Premise

the premise containing the major term

Minor Premise

the premise containing the minor term

Principle of Reciprocal Identity

two terms that are identical with a third term are identical to each other (If S = P and M = P then S = M)

Principle of Reciprocal Non-Identity

two terms, one of which is identical with a third term and the other of which is nonidentical with that third term, are nonidentical to each other

Dictum de Omni

what is affirmed universally of a certain term is affirmed of every term that comes under that term

Dictum de Nullo

what is denied universally of a certain term is denied of every term that comes under that term