Logic Flashcards

Challenge 1 Semester 1 Logic Vocab

What is logic?

The science of right thinking.

What are the two main branches of logic?

Formal (or minor) logic is interested in the form or structure of an argument.Material (or major) logic is concerned with the content of an argument.

What is validity in the study of logic?

an argument is valid when its conclusion follows logically from its premises.

What is truth in the study of logic?

Truth is the correspondence of a statement to reality.

What is soundness in the study of logic?

An argument is sound when it's both true and valid. 

What is simple apprehension?

The act by which the mind grasps the concept or general meaning of an object without affirming or denying anything about it. 

What is sense perception?

The act of seeing or hearing or smelling or tasting or touching.

What three things occur during simple apprehension?

1, we perceive a thing with our senses 2, We have a mental image of the thing 3, we conceive the meaning of the thing.

How is a mental image different from a concept?

A mental image is representative of a particular thing. Grasping a concept involves understanding univeral meaning, or the essence of the thing.

What is a mental image?

The image that forms in your mind after perceiving it with your senses. 

What is abstraction?

the process by which a simple apprehension is derived from a sense perception and mental image

What are the two properties of simple apprehension?

Comprehension and extension.

What is comprehension?

The essence of a thing. A completely and articulated sum of intelligeble aspects, or elements (notes) represented by a concept.

What is extension?

The thing to which the essence applies.

What is a term?

A word or group of words which verbally express a concept.

What are the two properties of a term?

Signification and supposition.

What three ways can terms be divided according to their signifiication?

univocal terms, equivocal terms, and analogous terms. 

What is an univocal term?

A term that has exactly the same meaning no matter when or how it is used. 

What are equivocal terms?

Terms that have entirely different and unrelated meanings, even though they are spelled and pronounced alike. 

What are analogous terms?

Terms that are applied to different things but have related meanings. Examples: “set of wheels”. 

What three ways can terms be divided according to their supposition?

verbal existence (material supposition), mental existence (logical supposition), and real existence (real supposition). 

What is material supposition?

Terms exist verbally.

What is logical supposition?

Terms refer to something as it exists logically

What is real supposition?

Terms refer to something as it exists in the real world. 

What is judgement?

The act by which the intellect unites by affirming or separates by denying. The mental act whose verbal expression is a proposition.

What is a proposition?

A sentence or statement that expresses truth or falsity.

What are the parts of a proposition?

subject-term, predicate-term, and copula (form of to be)

What is the logical form of a sentence?

the form which a sentence must be in, in order to be handled logically. It must contain a subject-term (noun), copula (is, am, are), and predicate-term (noun).

What are the four basic categorical propositions in logic?

A: All S is P I: Some S is P E: No S is P O: Some S is not P

What purpose do the qualifiers (all, some, no, and some….not) serve in categorical propositions?

Qualifiers show both the quality and quantity of a proposition.

What are the two qualities of propositions?

Affirmative – affirms the subject (A and I statements) Negative – negates the subject (E and O statements)

What are the two quantities of propositions?

Universal – says something about all members of the class referred to by the subject (A and E statements) Particular – says something only about some members of the class referred to by the subject (I and O statements)

What four ways can the A, I, E, and O statements be related in opposition?

contradictory, contrary, subcontrary, and subalternate

What is the Rule of Contradiction and which pair(s) of statements are contradictory?

Contradictory statements are statements that differ in both quality and quantity. A and O statements and E and I statements are contradictory

What is the First Law of Opposition?

Contradictories cannot at the same time

be true nor at the same time be false.

What is the Rule of Contraries and which pair(s) of statements are contrary?

Contrary statements are both universals

but differ in quality.

A and E statements are contrary.

What is the Second Law of Opposition?

Contraries cannot at the same time

both be true, but can at the same

time both be false.

What is the Rule of Subcontraries and which pair(s) of statements are subcontrary?

Subcontrary statements are both

particular but differ in quality.

I and O statements are subcontrary.

What is the Third Law of Opposition?

Subcontraries may at the same time

both be true, but cannot at the same

time both be false.

What is the Rule of Subalterns and which pair(s) of statements are subalterns?

Two statements are subalternate if they

have the same quality, but differ in

quantity.

A and I statements are subalterns.

E and O statements are subalterns.

What is the 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 cannot be

determined.

What is distribution?

The status of a term in regard to extension.

A term is distributed when it refers to all

the members of its class of things.

How do we determine the distribution of a subject term?

The subject-term is distributed in

universal statements (A and E) and

undistributed in particular statements

(I and O).

How do we determine the distribution of a predicate term?

The predicate-term is always taken

particulary in afirrmative propositions (A

and I) and thus is undistributed.

The predicate-term is always taken

universally in negative propositions (E

and O) and thus is distributed.

What are three ways to convert

propositions into their logical

equivalents?

obversion, conversion, and contraposition

What are the steps in

obverting a statement?

1. Change the quality

2. Negate the predicate

What are some ways to double

negate the predicate of

an I statement?

Use not not

Use not non-

Use im-, un-, or in-

Apply the rule of double negation, which

says that a term that is not negated is

equivalent to a term negated twice

What are the steps in

converting a statement?

Interchange the subject and predicate

(E and I statements only)

How do we partially convert

an A statement?

If an A statement is true, it can be

converted into a true I statement.

1. Switch the subject and predicate

2. Change from universal to particular

Example: All dogs are animals. --> Some

animals are dogs.

What are the steps of using

contraposition to convert a

statement into its equivalent?

Only A and O statements can use this

method.

1. Obvert the statement

2. Convert the statement

3. Obvert the statement again

How is reasoning defined?

The act by which the mind acquires new

knowledge by means of what it already

knows.

What are the two kinds of reasoning?

deduction (or deductive inference)

and induction

What is deductive inference?

The act by which the mind establishes a

connection between the antecedent and

the consequent.

What are the antecedent

and consequent?

The first two steps in an argument are

the antecedent. The conclusion is the

consequent.

What is a syllogism?

A group of propositions in orderly

sequence. The consequent (conclusion)

is inferred from the antecedent (the

other proposition).In a valid syllogism, if the antecedent is

true, the consequent must also be true.

What is the Essential Law of

Argumentation

In a valid syllogism, if the antecedent is

true, the consequent must also be true.

What are the two corollaries to the

Essential Law of Argumentation

?

In a valid syllogism:

1. If the consequent is false, the

antecedent (i.e. one or both of the two

premises) must be false.

2. If the consequent is true, the

antecedent is not necessarily true (i.e.

one or both of the premises may still be

false)

What are the three terms in

a syllogism and where are

they located?

Major term – predicate of the conclusion

Minor term – subject of the conclusion

Middle term – appears in both premises,

but not in the conclusion

What is the proper formation

of a syllogism?

Major premise is first and contains the

major term.

Minor premise is second and contains

the minor term.

The conclusion is third and contains

both the major and minor terms, but not

the middle term.

What is the Principle of

Reciprocal Identity

Two terms that are identical with a

third term are identical to each other.

Example: If S = M and P = M then S =

P

What is the Printiple 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.

Example If S ≠ M and P = M then S ≠ P

What is the Dictum de Omni?

What is affirmed universally of a certain

term is affirmed of every term that

comes under that term.