Intro to Logic

logic

the science that evaluates arguments

argument

a group of statements, one or more of which (the premises) are claimed to provide support for, or reasons to believe, one of the others (the conclusion)

statement

a sentence that is either true or false

premise

a statement in an argument that sets forth evidence

conclusion

the statement in an argument that the premises are claimed to support or imply

conclusion indicators

a word that provides a clue to identifying a conclusion

premise indicators

a word that provides a clue to identifying a premise

inference

the reasoning process expressed by an argument

proposition

the information content of a statement

syllogistic

a deductive argument consisting of two premises and one conclusion

syllogistic logic

the logic that deals with categorical propositions and categorical syllogistic

modal logic

a kind of logic that deals with concepts such as possibility, necessity, belief, and doubt

factual claim

a claim that something is true; a claim that evidence or reasons are being presented

inferential claim

a claim that alleged evidence or reasons support or imply something

warning

a form of expression intended to put someone on guard against a dangerous or detrimental situation

piece of advice

a form of expression that makes a recommendation about some future decision or course of conduct

statement of opinion

a kind of non-argument composed of statements that express the personal conviction of a speaker or writer without giving any evidence in support of that conviction

Llosely associated statements

statements that are about the same general subject and that lack an inferential relationship

report

a kind of non-argument consisting of one or more statements that convey information about some topic or event

expository passage

a kind of discourse that begins with a topic sentence followed by one or more sentences that develop the topic sentence

illustration

an expression involving one or more examples that is intended to show what something means or how it is done

arguments from example

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

explanation

an expression that purports to shed light on some event or phenomenon

explanandum

the component of an explanation that describes the event or phenomenon to be explained

explanans

the component of an explanation that explains the event or phenomenon indicated by the explanandum

conditional statement

an "if...then" statement

antecedent

the component of a conditional statement immediately following the word "if

consequent

the component of a conditional statement immediately following the word "then"; the component of a conditional statement that is not the antecedent

particular statement

A statement that makes a claim about one or more (but not all) members of a class

general statement

A statement that makes a claim about all the members of a class

prediction

An inductive argument that proceeds from knowledge of some event in the relative past to a claim about some other event in the relative future

argument from analogy

An inductive argument that depends on the existence of a similarity between two things or states of affairs

generalization

An inductive argument that proceeds from the knowledge of a selected sample to some claim about the whole group

argument from authority

An inductive argument in which the conclusion rests on the statement made by some presumed authority or witness

argument based on signs

An inductive argument that proceeds from the knowledge of a sign to a claim about the things or situation that the sign symbolizes

casual inference

An inductive inference that proceeds from knowledge of a cause to a claim about an effect, or from knowledge of an effect to a claim about a cause

argument from definition

A deductive argument in which the conclusion is claimed to depend merely on the definition of some word or phrase used in the premise or conclusion

categorical Syllogism

A syllogism in which all three statements are categorical propositions

hypothetical syllogism

A syllogism having a conditional statement for one or both of its premises

disjunctive syllogism

A syllogism having a disjunctive statement for one or both of its premises. (2) a valid argument form/rule of inference: "p or q/ not p//q

argument based on mathematics

A deductive argument in which the conclusion depends on some purely arithmetic or geometric computation or measurement

deductive argument

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

inductive argument

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

necessary condition

The condition represented by the consequent in a conditional statement

sufficient condition

the condition represented by the antecedent in a conditional statement

valid deductive argument

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

invalid deductive argument

A deductive argument in which it is possible for the conclusion to be false given that the premises are true

strong inductive argument

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

sound argument

a deductive argument that is valid and has all true premises

unsound argument

a deductive argument that is invalid, has one or more false premises, or both

weak inductive argument

An inductive argument in which the conclusion does not follow probably from the premises even though it is claimed to do so

cogent argument

An inductive argument that is strong and has all true premises

uncogent argument

An inductive argument that is weak, has one or more false premises, or both

substitution instance

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

counterexample method

A method for proving invalidity; consists in constructing a substitution instance having true premises and false conclusion