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Argument

A group of statements of which one (the conclusion) is claimed to follow from the others (the premises).

Statement

A sentence that is either true or false

Premise

The information intended to provide support for a conclusion

Conclusion

The statement that is claimed to follow from the premises of an argument

Logic

the study of reasoning

Truth Value

Every statement is either true or false

Proposition

The information content imparted by a statement, or, simply put, its meaning

Inference

A term used by logicians to refer to the reasoning process that is expressed by an argument

Conclusion indicator

Words and phrases that indicate the presence of a conclusion (the statement claimed to follow from premises).

Premise indicator

words and phrases that help us recognize arguments by indicating the presence of premises (statements being offered in support of a conclusion)

Inferential Claim

If a passage expresses a reasoning process- that the conclusion follows from the premises

Explanation

provides reasons for why or how an event occurred. By themselves, these are not arguments, however, they can form part of an argument.

Deductive Argument

An argument in which it is claimed that the conclusion follows necessarily from the premises. In other words, it is claimed that under the assumption that the premises are true it is impossible for the conclusion to be false.

Inductive argument

An argument in which it is claimed that the premises make the conclusion probable. In other words, it is claimed that under the assumption that the premises are true it is improbable for the conclusion to be false.

Valid deductive argument

An argument in which, assuming the premises are true, it is impossible for the conclusion to be false. In other words, the conclusion follows necessarily from the premises.

Invalid deductive argument

An argument in which, assuming the premises are true, it is possible for the conclusion to be false. In other words, the conclusion does not follow necessarily from the premises.

Sound Argument

When logical analysis shows that a deductive argument is valid, and when truth value analysis of the premises shows that they are all true

Unsound Argument

If a deductive argument is invalid, or if at least one of the premises is false (truth value analysis)

Counterexample

A counterexample to a statement is evidence that shows the statement is false. A counterexample to an argument shows the possibility that premises assumed to be true do not make the conclusion necessarily true. A single counterexample to a deductive argument is enough to show that the argument is invalid.

Strong inductive argument

An argument such that if the premises are assumed to be true, then the conclusion is probably true. In other words, if the premises are assumed to be true, then it is improbable that the conclusion is false.

Weak Inductive argument

An argument such that if the premises are assumed to be true, then the conclusion is not probably true.

Cogent argument

when an inductive argument is strong and the premises are true.

Uncogent argument

If an inductive argument is weak, or the argument has at least one false premise.

Term

A single word or group of words that can be the subject of a statement; it can be a common name, a proper name, or even a descriptive phrase.

Intension

The intension of a term is specified by listing the properties or attributes that the term connotes- in other words, its sense.

Extension

The class or collection of objects to which the term applies. In other words, what the term denotes (its reference).

Class

A group of objects

Empty class

A class that has zero members

Increasing intension

In a sequence of terms where each term after the first cannotes more attributes than the previous term (banana; fruit; food; commodity)

Decreasing extension

In a sequence of terms where each term after the first denotes a set of objects with fewer members than the previous term

Decreasing Intension

In a sequence of terms where each term after the first connotes fewer attributes than the previous term.

Increasing extension

In a sequence of terms where each term after the first denotes a set of objects with more members than the previous term

Definition

A definition assigns a meaning to a word, phrase, or symbol

Definiedndum

Refers to that which is being defined.

Definiens

Refers to that which does the defining

Intensional definition

Assigns a meaning to a term by listing the properties or attributes shared by all the objects that are denoted by the term.

Synonymous definition

Assigns a meaning to a term by providing another term with the same meaning in other words, by providing a synonym.

Operational definition

Defines a term by specifying a measurement procedure

Definition by genus and difference

Assigns a meaning to a term (the species) by establishing a genus an combining it with the attribute that distinguishes the members of that species.

Extensional definition

Assigns meaning to a term by indicating the class members denoted by the term

Ostensive definition

Involves demonstrating the term-for example, by pointing to a member of the class that the term denotes

Enumerative definition

Assigns meaning to a term by naming the individual members of the class denoted by the term

Definition by subclass

Assigns meaning to a term by naming subclasses (species) of the class denoted by the term.

Stipulative definition

Introduces a new meaning to a term or symbol

Lexical definition

A definition based on the common use of a word, term, or symbol.

Functional definition

Specifies the purpose or use of the objects denoted by the term.

Precising definition

Reduces the vagueness and ambiguity of a term by providing a sharp focus, often a technical meaning, for a term.

Theoretical definition

Assigns a meaning to a term by providing an understanding of how the term fits into a general theory.

Persuasive definition

Assigns a meaning to a term with the direct purpose of influencing attitudes or opinions.

Cognitive meaning

language that is used to convey information

Emotive meaning

Language that is used to express emotion or feelings has emotive meaning

Value Claim

A judgment that someone (or something) is good or bad, moral or immoral, or better or worse than another person (or thing).

Factual dispute

Occurs when people disagree on a matter that involves facts.

Verbal dispute

Occurs when a vague or ambiguous term results in a linguistic misunderstanding.

Independent premise

When the falsity of one premise would not nullify any support the others would give to the conclusion

Convergent diagram

A diagram that reveals the occurrence of independent premises.

Dependent premises

When premises act together to support a conclusion

Linked diagram

A diagram that reveals the occurrence of a dependent premise.

Divergent diagram

A diagram that shows a single premise supporting independent conclusions

Serial diagram

A diagram that shows that a conclusion from one argument is a premise in a second argument

Enthymemes

Arguments with missing premises, missing conclusions, or both

Principle of charity

We should choose the reconstructed argument that gives the benefit of the doubt to the person presenting the argument

Rhetorical language

When we speak or write for dramatic or exaggerated effect; that is, the language we employ may be implying things that are not explicitly said.

Rhetorical question

When a statement is disguised in the form of a question.

Rhetorical conditional

A conditional statement that is used to imply an argument

Rhetorical disjunction

A disjunction that is used to disguise a statement or an implied argument

Sufficient condition

Whenever one event ensures that another event will happen

Necessary condition

When one thing is essential, mandatory, or required in order for another thing to be realized.

Formal fallacy

A logical error that occurs in the form or structure of an argument; it is restricted to deductive arguments

Informal fallacy

A mistake in reasoning that occurs in ordinary language and is different from an error in the form or structure or arguments

Fallacies of relevance

Fallacies that occur whenever irrelevant premises are offered in support of a conclusion

Argument against the person

When a claim is rejected or judged to be false based on alleged character flaws of the person making the claim. A second common form occurs whenever someone's statement or reasoning is attacked by way of stereotype, such as a racial, sexual, or religious stereotype. A third form involves the use of circumstances of a person's life to reject his claims.

Tu quoque

A variety of ad hominem fallacy that is distinguished by the specific attempt of one person to avoid the issue at hand by claiming the other person is a hypocrite

Appeal to the people

The avoidance of objective evidence in favor of an emotional response defeats the goal of a rational investigation of truth. The tactic appeals to people's desire to belong to a group

Appeal to pity

A specific kind of emotional plea that relies solely on a sense of pity for support

Appeal to force

A threat of harmful consequences (physical and otherwise) used to force acceptance of a course of action that would otherwise be unacceptable

Appeal to ignorance

An argument built on a position of ignorance claims either that (1) a statement must be true because it has not been proven to be false or (2) a statement must be false because it has not been proven to be true.

Missing the point

When the premises that seem to lead logically to one conclusion are used instead to support an unexpected conclusion

Appeal to an unqualified authority

An argument that relies on the opinions of people who have no expertise, training, or knowledge relevant to the issue at hand.

Fallacies of unwarranted assumption

Arguments that assume the truth of some unproven or questionable claim

Begging the question

An argument that assumes as evidence in the premises the very thing that it attempts to prove in the conclusion

complex question

A single question that actually contains multiple, hidden parts.

Biased sample

An argument that uses a nonrepresentative sample as support for a statistical claim about an entire population

Accident

When a generalization is inappropriately applied to the case at hand.

Hasty generalization

A generalization created on the basis of a few instances

Misleading precision

A claim that appears to be statistically significant but is not

False dichotomy

A fallacy that occurs when it is assumed that only two choices are possible, when in fact others exist.

False dilemma

A fallacy that occurs when two choices are asserted, each leading to an unwanted result, but there is a failure to acknowledge that other possibilities exist.

False cause

A fallacy that occurs when a casual connection is assumed to exist between two events when none actually exists

Coincidence

A fallacy that results from the accidental or chance connection between two events.

Post hoc fallacy

A fallacy involving either a short-term or long-term pattern that is noticed after the fact.

Common cause fallacy

A mistake that occurs when someone thinks that one event causes another, when in fact both events are the result of a common cause

Slippery slope

An argument that attempts to make final event the inevitable outcome of an initial act.

Fallacy of ambiguity or diversion

A fallacy that occurs when the meanings of terms or phrases are changed (intentionally or unintentionally) within the argument, or when our attention is purposely (or accidentally) diverted from the issue at hand.

Equivocation

The intentional or unintentional use of different meanings of words or phrases in an argument. "Judy said she had a hot date last night, therefore her air conditioner in her apartment must be broken."

Amphibloy

Ambiguity that arises when a poorly constructed statement muddles the intended meaning. "He was shot in the train in the back of the sleeping car." - We can conclude either the victim was shot in the back or the shooting occurred in the sleeping car which is in the back of the train.

Composition

The mistaken transfer of an attribute of the individual parts of an object to the object as a whole. "All the cells in the body are tiny, thus, he is tiny."

Division

The mistaken transfer of an attribute of an object as a whole to its individual parts. Opposite of composition. "He is tiny, thus he has tiny cells."

Emphasis

A fallacy that occurs when attention is purposely (or accidentally) diverted from the issue at hand.

Straw man Fallacy

A fallacy that occurs when someone's written or spoken words are taken out of context. It purposely distorts the original argument to create a new, weak argument that can be easily refuted

Red herring

A fallacy that occurs when someone completely ignores an opponent's position and changes the subject, diverting the discussion in a new direction.

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