PHIL 2010: Logic Terms

Argument

is any group of statements of which one is claimed to follow from the others.

This set of terms are related both to Aristotle and intro. to logic comments.

Premise

is/are the proposition(s) doing the supporting of some other single proposition called a conclusion.

Conclusion

is the single proposition being supported in a group of propositions. An argument has one conclusion.

Premise Indicator Words

are words between propositions which signal the premise follows. Examples include: because, since, may be inferred from and follows from.

Conclusion Indicator Words

are words between propositions which signal that the conclusion follows. Examples include: therefore, hence, consequently, I conclude that, it follows that, and shows that.

Proposition or Statement

is grammatically a declarative sentence which must be true, false or indeterminate.

Logic

is the study of methods for evaluating arguments and describing how reasons that should hold for anyone, anywhere without respect to feelings, sympathies or prejudices lead to particular conclusions.

Rhetoric

is the art of using writing and speech to persuade others and usually involves personal appeals to various emotions like humor, sympathy and fear.

Deductive Argument

occurs when an author claims the conclusion is intended to necessarily follow from the premises. Deductive arguments can be valid or invalid.

Inductive Argument

occurs when an author claims the premises make the conclusion highly probable. Inductive logic focuses on having conclusions follow the premises with a high degree of probability.

Inductive arguments can be strong or weak relative to a scale of probability.

A valid argument

is a deductive argument in which if the premises are true, then the conclusion must be true. It is impossible in a valid argument for the premises to be true and the conclusion false.

A sound argument

is a valid deductive argument which has true premises. A valid deductive argument can be either sound or unsound.

A cogent argument

is an inductive argument with true premises which make the conclusion highly probable. No inductive argument gives certainty or necessity in its conclusion, only varying degrees of probability.