Chapter 1: Basic Concepts

Criteria for an argument

1. At least one of the statements much claim to present evidence or reasons 2. There must be a claim that the alleged evidence supports or implies something ( a claim that something follows from the alleged evidence or reasons

Invalid Deductive arguments

A deductive argument in which it IS possible for the conclusion to be false given the premises are true. EX: All banks are financial institutions. Wells Fargo is a financial institution. Therefore, Wells Fargo is a bank. Premises are true, but it is possible for the conclusion to be false.

Sound argument

A deductive argument that is valid and has all true premises

Unsound argument

A deductive argument that is valid, has one or more false premises, or both

Argument

A group of statements, one or more of which are claimed to provide support for one of the others A group of statements

Sufficient condition

A is a SC for B whenever the occurrence of A is needed for the occurrence of B

Expository Passage

A kind of discourse that begins with a topic sentence followed by one or more sentences that develop the topic sentence. If the objective is not to prove the topic sentence, but only to expand it or elaborate it, then there is no argument When trying to determine if an expository passage is an argument, try to determine whether the purpose of the subsequent sentences is to develop the topic or prove that it is true

Syllogistic Logic

A kind of logic in which the fundamental elements are terms, and arguments are evaluated as good or bad depending on how the terms are arranged in the argument

Modal Logic

A kind of logic that involves such concepts as possibility, necessity, belief, and doubt

Statement

A sentence that is either true or false.

Form for valid arguments

All A are B. All C are A. Therefore, All C are B.

Invalid argument form

All A are B. All C are B. All A are C. Can prove this invalid if you find a substitution instance having actually true premises and an actually false conclusion.

Uniformity of Nature

All inductive arguments depend on this. The ultimate basis for our judgements about what we naturally expect to occur. Good inductive arguments are those that accord with this. They have conclusions that we naturally expect to turn out true.

Valid Deductive argument

An argument in which it is impossible for the conclusion to be false given that the premises are true. EX: All automakers are computer manufacturers. United Airlines is an automaker. Therefore, United Airlines is a computer manufacturer Even though the premises are false, the conclusion is true given the premises, so the argument is valid.

Strong inductive argument

An argument in which it is improbable that the conclusion be false given that the premises are true

Weak inductive argument

An argument in which the conclusion does not follow probably from the premises, even though it is claimed to.

Deductive Argument

An argument incorporating the claim that it is impossible for the conclusion to be false given that the premises are true

Inductive Argument

An argument incorporating the claim that it is improbable that the conclusion be false given that the premises are true

Substitution instance

An argument or statement that has the same form as a given argument form or statement form; of an argument form

Arguments from Example

An argument that purports to prove something by giving one or more examples of it

Argument form

An arrangement of letters and words such that the uniform substitution of words and phrases in the place of the letters results in an argument

Illustration

An expression involving one or more examples that is intended to show what something means or how it is done. To determine if its an argument, determine whether the passage merely shows how something is done or what something means, or whether it also purports to prove something.

Explanation

An expression that purports to shed light on some event or phenomenon. The event in question is usually accepted as a matter of fact Components of an explanation are: explanandum and explanans

Conditional Statement

An if, then statement Not arguments, but may serve as a premise or conclusion

Cogent argument

An inductive argument that is strong and has all true premises (in the sense of meeting the total evidence requirement)

Uncogent argument

An inductive argument that is weak, has one or more false premises, fails to meet the total evidence requirement, or any combination of these

Necessary Condition

B is a NC for A whenever A cannot occur without the occurrence of B

Report

Consists of a group of statements that convey information about some topic or event

Counterexample method

Consists of isolating the form of an argument and then constructing a substitution instance having true premises and a false conclusion. This proves the form invalid, which in turn proves the argument invalid.

Total evidence requirement

Dealing with true premises When we say a premise is true, we mean in a complete sense. They cannot exclude or overlook some crucial piece of evidence that undermines the stated premises and requires a different conclusion

Disjunctive Syllogism

Deductive argument form A syllogism having a disjunctive (either...or) statement. EX: Either global warming will be arrested, or hurricanes will become more intense. Global warming will not be arrested. Therefore, hurricanes will become more intense.

Argument based on mathematics

Deductive argument form An argument in which the conclusion depends on some purely arithmetic or geometric computation or measurement EX: A shopper might have two apples and three oranges in a paper bag and conclude that the bag contains five pieces of fruit

Hypothetical Syllogism

Deductive argument form A syllogism having a conditional ("if...then") statement for one or both of its premises EX: If estate taxes are abolished, then wealth will accumulate disproportionately. If wealth accumulates disproportionately, then democracy will be threatened. Therefore, if estate taxes are abolished, then democracy will be threatened.

Categorical Syllogism

Deductive argument form A syllogism in which each statement begins with all, no, or some EX: All ancient forests are sources of wonder. Some ancient forests are targets of the timber industry. Therefore, some sources of wonder are targets of the timber industry

Argument from definition

Deductive argument form An argument in which the conclusion is claimed to depend merely on the definition of some word or phrase used in the premise or conclusion Ex: Because Claudia is mendacious, it follows that she tells lies.

Validity

Determined by the relationship between premises and conclusion. Question is whether the premises support the conclusion Any argument with all true premises and a false conclusion is invalid

Implicit Claim

Exists if there is an inferential relationship between the statements in a passage, but the passage contains no indicator words

Aristotle

Father of logic First devised systematic criteria for analyzing and evaluating arguments

Leibniz

Father of symbolic logic

Antecedent

In a conditional statement, the statement following the "if"

Argument from Authority

Inductive argument form An argument that concludes something is true because a presumed expert or witness has said that it is EX: a lawyer might argue that Mack the Knife committed the murder because an eyewitness testified to that effect under oath.

Argument from analogy

Inductive argument form An argument that depends on the existence of an analogy, or similarity, between two things or states of affairs. Because of the existence of this analogy, a certain condition that affects the better-known thing or situation is concluded to affect the similar, lesser-known thing/situation EX: Because my Porsche is great at handling, my sister's Porsche must also be a great-handling car.

Prediction

Inductive argument form An argument that proceeds from our knowledge of the past to a claim about the future EX: Because certain meteorological phenomena have been observed to develop in Missouri, a storm will occur there in six hours.

Generalization

Inductive argument form An argument that proceeds from the knowledge of a selected sample to some claim about the whole group. Because the members of the sample have a certain characteristic, it is argued that all members of the group have the same characteristic. EX: Because three oranges are especially tasty and juicy, all the oranges are especially tasty and juicy

Causal Inference

Inductive argument form An argument that proceeds from knowledge of a cause to a claim about an effect, or, conversely, from knowledge of an affect to a claim about a cause EX: rom the knowledge that a bottle of wine had been accidentally left in the freezer overnight, someone might conclude that it had frozen (cause to effect) EX2: After tasting a piece of chicken and finding it dry and tough, one might conclude that it had been overcooked (effect to cause)

Argument based on signs

Inductive argument form An argument that proceeds from the knowledge of a sign to a claim about the thing or situation that the sign symbolizes. Sign means any kind of message produced by an intelligent being EX: When driving on an unfamiliar road, one might see a sign indicating that the road makes several sharp turns one mile ahead and can conclude that there are indeed sharp turns

Warning

Intended to put someone on guard against a dangerous or detrimental situation

General statement

Makes a claim about ALL members of a class

Piece of advice

Makes a recommendation about some future decision or course of conduct

Loosely associated statements

May be about the same general subject, but they lack a claim that one of them is proved by the others

Deductive indicator words

Necessarily certainly definitely absolutely

Particular statement

One that makes a claim about one or more particular members of a class

Inductive indicator words

Probably Improbable plausible implausible likley unlikely reasonable to conclude

Premise indicators

Since As indicated by Because For In that May be inferred from As Given that Seeing that For the reason that In as much as Owing to

Explanandum

Statement that describes the event or phenomenon to be explained

Premises

Statements that set forth the reasons or evidence ONLY statements that are actually intended to support the conclusion should be included in the list of premises

Truth values

The attribute by which a statement is either true or false

Proposition

The meaning or information content of a statement

Deductive Argument Example

The meercat is a member of the mongoose family All members of the mongoose family are carnivores. Therefore, it necessarily follows that the meercat is a carnivore.

Inductive Argument Example

The meercat is closely related to the suricat. The suricat thrives on beetle larvae. Therefore, the meercat probably thrives on beetle larvae.

Inference

The reasoning process expressed by an argument

Logic

The science that evaluates arguments Aim is to develop a system of methods and principles that we can use as criteria for evaluating the arguments of others and as guides in constructing arguments of our own Purpose of logic is to allow us to distinguish good arguments from bad

Consequent

The statement following the "then" in a conditional statement

Conclusions

The statement that the evidence is claimed to support or imply

Explanans

The statement/group of statements that purports to do the explaining Shows why something is the case

Conclusion Indicators

Therefore Wherefore Thus Consequently We may infer Accordingly We may conclude It must be that For this reason So Entails that Hence It follows that Implies that As a result

Simple non-inferential passages

Unproblematic passages that lack a claim that anything is being proved Include: warnings, pieces of advice, statements of belief or opinions, loosely associated statements, and reports

Explicit claim

Usually asserted by premise or conclusion indicator words (thus, since, because, hence, therefore, and so on)

Syllogism

an argument consisting of exactly two premises and a conclusion

Statement of belief/opinion

expression about what someone happens to believe or to think about something

Things that are not statements

questions, proposals, suggestions, commands, and exclamations