Logic and Fallacies

Question 1

Definition: Post hoc, ergo proctor hoc

Answer 1

After this, therefore because of this

Question 2

What is a declarative sentence?

Answer 2

A grammatical sentence that can be put in place of x in:

Is it true that x?

Question 3

What is lexical ambiguity?

Answer 3

Where a word can be understood in more than one way.

Question 4

What is structural ambiguity?

Answer 4

Where words in the string can be grouped together in different ways.

Question 5

What is ambiguity of cross reference?

Answer 5

When a word or phrase refers back to something mentioned elsewhere, but isn’t clear which thing.

Question 6

What does token-reflexive mean?

Answer 6

Words or phrases whose reference depends on the context in which they are uttered.

Question 7

What does cross referencing mean?

Answer 7

Words or phrases that have a reference which depends entirely on the reference of some previously used phrase.

Question 8

What is referential failure?

Answer 8

When a phrase that ought to have (a real) reference has none.

Question 9

What is a scaling adjective?

Answer 9

Words that cover a scale, in which the same word applies for more or less, e.g. fat, happy, expensive, heavy.

Question 10

What is a borderline case?

Answer 10

Where a specific example is somewhere on the border between descriptions, e.g. when someone isn’t obviously definitely fat or thin, bald or non-bald.

Question 11

When can a set of declarative sentences be described as consistent?

Answer 11

If there is some possible situation in which all the sentences are true.

Question 12

What does monotonocity entail?

Answer 12

You cannot remove an inconsistency by adding more sentences.

Though you could modify existing sentenced through reference?

Question 13

In Logic, what does it mean to say a situation is possible?

Answer 13

That it could have been the actual situation (we put aside what we know about the world).

Question 14

When is an argument valid?

Answer 14

If there is no possible situation in which its premises are all true and its conclusion is not true. When an argument is valid, its premises are said to entail its conclusion.

Question 15

What are necessary truths?

Answer 15

Declarative sentences which are true in every possible situation.

Question 16

What is a rational argument?

Answer 16

One which has premises that give us good reason to believe the conclusion, even if the reason is not absolutely decisive.

Question 17

p => q

Answer 17

Implication

P = antecedent
Q = consequent

Question 18

Material implication?

Answer 18

Basic cause and effect. Only false when cause and effect is violated, otherwise true.

P therefore Q
Only false implication if P is true and Q is false.

Question 19

Denying the antecedent

Answer 19

If P, then Q
Not P
Therefore not Q

P is only sufficient, not necessary, so it’s absence does not entail the absence of Q.

Question 20

Biconditional

Answer 20

True if the truth values of the constituents agree.

Question 21

What makes a sentence valid?

Answer 21

If and only if every interpretation satisfies it.

Question 22

What makes a sentence contingent?

Answer 22

If and only if some interpretation satisfies it and some interpretation falsifies it.

Question 23

What makes a sentence unsatisfiable?

Answer 23

If and only if no interpretation satisfies it.

Question 24

De Morgan’s Laws

Answer 24

~(X&Y) is logically equivalent to ~Xv~Y

and

~(XvY) is logically equivalent to ~X&~Y

Question 25

The Distributive Law

Answer 25

X&(YvZ) is the same as (X&Y)v(X&Z)

and

Xv(Y&Z) is the same as (XvY)&(XvZ)

Question 26

Antecedent?

Answer 26

The IF / prior part of a conditional

Question 27

Consequent?

Answer 27

The THEN part of a conditional

Question 28

Modus Ponens

Answer 28

If P then Q
P
Therefore Q

(‘Arrow/implication elimination’)

Question 29

Premise versus assumption

Answer 29

Premise asserted to be true. Categorical reasoning.

Assumptions assumed. Hypothetical reasoning.

Question 30

Affirming the Antecedent

Answer 30

Modus Ponens

If P then Q
P
Therefore Q

(‘Arrow/implication elimination’)

Question 31

Affirming the consequent

Answer 31

Invalid reasoning:

If P then Q
Q
Therefore P

Question 32

Denying the antecedent

Answer 32

Invalid

If P then Q
~ P
Therefore ~Q

Question 33

Denying the consequent

Answer 33

Valid

If P, then Q
~ Q
Therefore ~P

Question 34

Modus Tollens

Answer 34

Denying the consequent

Question 35

Disjunction

Answer 35

Or

Question 36

Conditional

Answer 36

->

If… Then…

Question 37

Conjunction

Answer 37

And

Question 38

Biconditional

Answer 38

If and only if

Question 39

Law of Identity

Answer 39

P -> P

Question 40

Modus Tollens

Answer 40

P -> Q
~ Q
Therefore ~ P

Question 41

Proposition

Answer 41

Statement believed to be true and presented as arguments or reasons for consideration. May be true or false.

Question 42

Predicate

Answer 42

The foundation of the argument / underlying assumption

The thing being asserted

In “John went home” it is “went home”

Question 43

Principle of Bivalence

Answer 43

Every sentence is either true or false but not both and not neither

Question 44

Law of excluded middle

Answer 44

P v ~P

Question 45

Abduction

Answer 45

Reasoning from effects to possible causes

Question 46

Commutativity

Answer 46

If you swap the order around it has the same value (e.g. for + and * but not - and /)