Subcontrary and Subalternate Statements The second two - - PDF document

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Jun 24, 2023 600 likes •713 views

Three Acts of the Mind Mental Act : Verbal Expression: Simple Term Apprehension Proposition Judgment Syllogism Deductive Inference Slide 7-1 Subcontrary and Subalternate Statements The second two relationships of

SLIDE 1

1

Three Acts of the Mind

Simple

Apprehension

Judgment
Deductive Inference
Term
Proposition
Syllogism

Verbal Expression:

Slide 7-1

Mental Act:

Subcontrary and Subalternate Statements

The second two relationships of

pposition

The Rule of Subcontraries The Third Law of Opposition The Rule of Subalterns The Fourth Law of Opposition

Slide 7-2

SLIDE 2

2

The Second Two Relationships of Opposition

Contradictory Contrary Subcontrary Subalternate

Slide 7-3

Rule of Subcontraries

Two statements are subcontrary if they are both particular statements that differ in quality.

Slide 7-4

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3

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

Slide 7-5

The Third Law of Opposition

If “Some men are mortal” is false, then “Some men are not mortal cannot be false .

Slide 7-6

The Third Law

f Opposition

an example:

SLIDE 4

4

Subcontrary Statements

I: Some men are mortal O: Some men are not mortal

Slide 7-7 Slide 7-8

Quantity and Quality

f the Four

Categorical Statements

Quality

Affirmative Negative Universal A contraries E

Quantity

Particular I subcontraries O

SLIDE 5

5

The Rule of Subalterns

Two statements are subalternate if they have the same quality, but differ in quantity.

Slide 7-9

Subalternate Statements

A: All men are mortal I: Some men are mortal

Slide 7-10

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6

Subalternate Statements

E: No men are mortal O: Some men are not mortal

Slide 7-11

The Fourth Law of Opposition

Subalterns may both be true or both be false. If the particular is false, then the universal is false; if the universal is true, then the particular is true; otherwise, their status cannot be determined.

Slide 7-12

SLIDE 7

7

The Fourth Law

f Opposition:

an example

If we know that “All dogs are mammals” is true, then we know that “Some dogs are mammals” is true. But if we know “Some dogs are long-haired” is true, we will not therefore know that “All dogs are long- haired” is true.

Slide 7-13