Chapter 1: What is logic?

Question 1

Logic is …

Answer 1

… the study of the methods and principles used to distinguish between good and bad reasoning.

Question 2

It is a _ discipline.

Answer 2

Normative.

Question 3

It is a normative discipline …

Answer 3

… in the sense that it does not survey and describe how we actually reason (which is the job of the psychologist) but what we should do in reasoning.

Question 4

An argument is …

Answer 4

… a structure that comprises a conclusion, namely, a proposition that one wants to uphold, and some premises, as reasons to support the belief in the conclusion.

Question 5

Logic is about …

Answer 5

… whether and how a conclusion follows from the premises.

Question 6

An argument contains __ and only __ conclusion.

Answer 6

One, one.

Question 7

An argument is individuated by …

Answer 7

… its conclusion.

Question 8

To have more than one conclusion …

Answer 8

… there must be more than one argument.

Question 9

A conclusion is supposed to be supported by the …

Answer 9

… premises.

Question 10

The minimum number of required premises is …

Answer 10

… (formally) zero.

Question 11

When logicians allow an argument to have no premises, it merely means that …

Answer 11

… nothing goes against the conclusion, rather than that the conclusion is supported by no reason. Such a conclusion is regarded as self-evident.

Question 12

Self-evident truths are obvious truths that do not need …

Answer 12

… anything to support them.

Question 13

It can be said that everything supports self-evident truths because …

Answer 13

… nothing counts as a reason to reject them, and they do not contradict with anything.

Question 14

Three laws of logic are …

Answer 14

The Law of Identity, The Law of Excluded Middle, and The Law of Contradiction or Noncontradiction

Question 15

Contingent truths can be self-evident truths if …

Answer 15

… they are very intuitive and hardly anything counts to refute them.

Question 16

Always identify the __ first and then trace back to the __ supporting it.

Answer 16

Conclusion, premises.

Question 17

Premise-indicators are …

Answer 17

… words typically indicating which sentence is a premise.

Question 18

Premise-indicator - examples:

Answer 18

because, since, for, as, follows from, as shown by, inasmuch, as indicated by, the reason is that, for the reason that, may be inferred / derived / deduced from, in view of the fact that…

Question 19

Conclusion-indicators are …

Answer 19

… words typically indicating which sentence is a conclusion.

Question 20

Conclusion-indicator - examples:

Answer 20

therefore, so, hence, thus, in consequence, consequently, accordingly, as a result, for this reason, it proves that, it follows that, we may infer, which allows us to infer that, which shows / means / entails / implies that, which points to the conclusion that…

Question 21

Arguments that have a missing premise, or premises, or even a missing conclusion are called …

Answer 21

… elliptical arguments.

Question 22

With elliptical arguments …

Answer 22

… one has to fill in the missing parts in order to reveal the full reasoning behind them.

Question 23

Elliptical arguments often …

Answer 23

… involve contextual interpretation(s) and as such, controversy may arise as to whether the interpretation(s) is/are correct.

Question 24

A rhetorical question …

Answer 24

… Sometimes a question is asked, or an exclamation is made, yet the point of the utterance is not really to enquire or to express emotion. Rather, an implicit proposition is presented, though in the form of a difference mood of speech.

Question 25

In clarifying an argument, we often need to grasp the implied or hidden meaning from …

Answer 25

… relevant context, make it explicit and state it in the form of a proposition or an assertion instead.

Question 26

Sometimes there may be arguments within a bigger argument; these smaller arguments are called …

Answer 26

… sub-arguments.

Question 27

Sub-arguments generate a conclusion and the conclusion is used again as a premise to …

Answer 27

... another argument, such that eventually a different, usually more general, conclusion is reached.

Question 28

Because the conclusion of a sub-argument is linked to other arguments, sometimes the whole argument can also be called a …

Answer 28

… chain argument.

Question 29

Chain argument technically refers to a particular form of argument called …

Answer 29

...hypothetical syllogism.

Question 30

Hypthetical syllogisms are …

Answer 30

… short, two-premise deductive arguments, in which at least one of the premises is a conditional, the antecedent or consequent of which also appears in the other premise.

Question 31

Chain argument (hypothetical syllogism) form:

Answer 31

A → B. B → C. Therefore, A → C.

Question 32

Sometimes our actual use of language may contain hidden …

Answer 32

… assumptions or implicit premises.

Question 33

An implicit premise is …

Answer 33

… an unstated assumption that is necessary for an argument to hold true. 

Question 34

There are at least two main types of inferences. They are ...

Answer 34

… induction and deduction.

Question 35

Induction …

Answer 35

… the conclusion is only probably true, rather than definitely true. In other words, the conclusion is likely to be true though it could be false even when the premises are true.

Question 36

Deduction …

Answer 36

… even though the premises might not actually be true, we can already decide whether the conclusion would follow or not. We can say that the truth of the premises completely determines the truth of the conclusion given the validity of the argument.

Question 37

Inductive arguments are evaluated as …

Answer 37

… strong or weak.

Question 38

All inductive arguments are in fact …

Answer 38

… invalid.

Question 39

Three notes about induction:

Answer 39

1. Achieves probability: if the premises are true, then the conclusion is likely to be true, although it does not have to be true. 2. Adding new premises may alter the strength of the argument. 3. Increases empirical knowledge.

Question 40

Deductive arguments are described as …

Answer 40

…valid or invalid.

Question 41

Three notes about deduction:

Answer 41

1. Achieves certainty: for a deductively valid argument, if the premises are true, then the conclusion must be true. 2. Adding new premises may not lead to a stronger argument. 3. The conclusion is already contained in the premises; hence, in a manner of speaking, no new knowledge is involved.

Question 42

The main task of logic is not to just identify an argument but also to …

Answer 42

… evaluate it.

Question 43

Two criteria used to evaluate an argument:

Answer 43

1. The truth of individual statements (premises and conclusion). 2. The validity of the whole argument.

Question 44

Truth and validity – Can a statement (a premise or a conclusion) be valid or invalid? Likewise, can an argument be true or false?

Answer 44

No, they can’t. A statement is true or false; yet only an argument can be valid or invalid.

Question 45

Validity is a relation __, rather than a __ by itself.

Answer 45

Between statements, property of an individual statement.

Question 46

Validity indicates whether …

Answer 46

… the conclusion follows if the premises are true.

Question 47

Only a statement can be …

Answer 47

… true or false.

Question 48

An argument contains statements which are __, but the argument itself is not __.

Answer 48

Ture or false, true or false.

Question 49

We say an argument is __, not that it is __.

Answer 49

Valid, true.

Question 50

Truth is …

Answer 50

… whatever is the case.

Question 51

An argument is valid if and only if the conclusion follows the premises. Such a relation between premises and conclusions is called …

Answer 51

… validity.

Question 52

An argument is __ if and only if the conclusion follows the premises; the conclusion cannot be __ if all the premises are true.

Answer 52

Valid, false.

Question 53

Any argument that is not valid is __.

Answer 53

Invalid.

Question 54

A strategy in which the reasoner provides two arguments with the same argument form, one obviously valid or invalid while the other is not so obvious is …

Answer 54

Logical analogy.

Question 55

An argument with a true premises and false conclusion can be a valid argument. Yes/No

Answer 55

No. If both an argument is valid and all its premises are true, then the conclusion must be true.

Question 56

An argument with true premises and a true conclusion is always a valid argument. Yes/No

Answer 56

No. Validity is about the relation between premises and conclusion, that if the premises are true, then the conclusion cannot be false.

Question 57

An argument with one or more premises which are false could have a true conclusion and be a valid argument. Yes/No

Answer 57

Yes.

Question 58

Can there be valid arguments with false premises and a false conclusion?

Answer 58

Yes.

Question 59

Sound arguments are …

Answer 59

… arguments where the argument is valid and the premises are all true.

Question 60

Two types of sound arguments are:

Answer 60

Cogent and Not cogent.

Question 61

A cogent argument refers to …

Answer 61

… any argument (including inductive argument) whose premises are acceptable, relevant to, and sufficient for its conclusion.

Question 62

Three criteria of good arguments are:

Answer 62

Validity, soundness, and cogency.

Question 63

Validity …

Answer 63

… an argument is valid if and only if its conclusion is true whenever all its premises are true.

Question 64

Soundness …

Answer 64

… an argument is sound if and only if it is a valid argument and all its premises are true.

Question 65

Cogency …

Answer 65

… an argument is cogent if and only if its premises are acceptable, relevant to, and sufficient for its conclusion.

Question 66

A priori knowledge is …

Answer 66

... knowledge that does not require justification from any empirical evidence.

Question 67

Innate knowledge is …

Answer 67

... knowledge that is inborn and not a product of experience.

Question 68

Reasoning can be formulated in …

Answer 68

... the form of an argument, a structure comprised of exactly one conclusion and reasons to support it called premises.

Question 69

We need to correctly understand and analyze an argument in …

Answer 69

… context.

Question 70

Arguments are divided into two types:

Answer 70

Deductive and inductive.

Question 71

A deductive argument is an argument …

Answer 71

… in which the truth of the premises completely determines the truth and conclusion when the argument is valid.

Question 72

An inductive argument is an argument …

Answer 72

... in which the conclusion is likely to be true, although it can be false even when the premises are true.

Question 73

To evaluate an argument we look for three criteria:

Answer 73

Validity, soundness, and cogency.

Question 74

An argument is valid …

Answer 74

… if and only if the conclusion cannot be false when all the premises are true.

Question 75

A sound argument is a valid argument …

Answer 75

... with all true premises.

Question 76

A cogent argument is ...

Answer 76

... a convincing argument with evidently true premises.