101 terms

# Logic

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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
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
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.