A group of statements of which one (the conclusion) is claimed to follow from the others (the premises).
A term used by logicians to refer to the reasoning process that is expressed by an argument
Words and phrases that indicate the presence of a conclusion (the statement claimed to follow from premises).
words and phrases that help us recognize arguments by indicating the presence of premises (statements being offered in support of a conclusion)
If a passage expresses a reasoning process- that the conclusion follows from the premises
provides reasons for why or how an event occurred. By themselves, these are not arguments, however, they can form part of an 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.
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.
When logical analysis shows that a deductive argument is valid, and when truth value analysis of the premises shows that they are all true
If a deductive argument is invalid, or if at least one of the premises is false (truth value analysis)
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.
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.
The intension of a term is specified by listing the properties or attributes that the term connotes- in other words, its sense.
The class or collection of objects to which the term applies. In other words, what the term denotes (its reference).
In a sequence of terms where each term after the first cannotes more attributes than the previous term (banana; fruit; food; commodity)
In a sequence of terms where each term after the first denotes a set of objects with fewer members than the previous term
In a sequence of terms where each term after the first connotes fewer attributes than the previous term.
In a sequence of terms where each term after the first denotes a set of objects with more members than the previous term
Assigns a meaning to a term by listing the properties or attributes shared by all the objects that are denoted by the term.
Assigns a meaning to a term by providing another term with the same meaning in other words, by providing a synonym.
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.
Assigns meaning to a term by indicating the class members denoted by the term
Involves demonstrating the term-for example, by pointing to a member of the class that the term denotes
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.
Reduces the vagueness and ambiguity of a term by providing a sharp focus, often a technical meaning, for a term.
Assigns a meaning to a term by providing an understanding of how the term fits into a general theory.
Assigns a meaning to a term with the direct purpose of influencing attitudes or opinions.
A judgment that someone (or something) is good or bad, moral or immoral, or better or worse than another person (or thing).
When the falsity of one premise would not nullify any support the others would give to the conclusion
A diagram that shows that a conclusion from one argument is a premise in a second argument
Principle of charity
We should choose the reconstructed argument that gives the benefit of the doubt to the person presenting the argument
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.
When one thing is essential, mandatory, or required in order for another thing to be realized.
A logical error that occurs in the form or structure of an argument; it is restricted to deductive arguments
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.
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 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
An argument that uses a nonrepresentative sample as support for a statistical claim about an entire population
A fallacy that occurs when it is assumed that only two choices are possible, when in fact others exist.
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.
A fallacy that occurs when a casual connection is assumed to exist between two events when none actually exists
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
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.
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."
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.
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."
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."
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