Chapter 3- PHIL

truth-preserving

A characteristic of a valid deductive argument in which the logical structure guarantees the truth of the conclusion if the premises are true.

Syllogism

A deductive argument made up of three statements- two premises and a conclusion. See modus ponens and modus tollens.

Invalid argument

A deductive argument that fails to provide conclusive support for its conclusion.

Sound argument

A deductively valid argument that has true premises.

Dependent Premise

A premise that depends on at least one other premise to provide joint support to a conclusion. If dependent premise is removed, the support that its linked dependent premises supply to the conclusion is undermined or completely canceled out.

Independent Premise

A premise that does not depend on other premises to provide support to a conclusion. If an independent premise is removed, the support that other premises supply to the conclusion is not affected

Cogent Argument

A strong inductive argument with all true premises

Modus Ponens (Affirming the Antecedent)

A valid argument form: If p, then q. p. Therefore, q.

Modus Tollens (Denying the Consequent)

A valid argument form: If p, then q. Not q. Therefore, not p.

Dysjunctive Syllogism

A valid argument form: Either p or q. Not p. Therefore, q. In the syllogism's second premise, either disjunct can be denied

Hypothetical Syllogism

A valid argument made up of three hypothetical, or conditional, statements: If p then q. If q, then r. Therefore, if p, then r.

Conditional Statement

An "if-then" statement; it consists of the antecedent (the part introduced by the word if) and the consequent (the part introduced by the word then).

Deductive argument

An argument intended to provide logically conclusive support for its conclusion.

weak argument

An inductive argument that fails to provide strong support for its conclusion.

Strong argument

An inductive argument that succeeds in providing probable-but not conclusive-support for its conclusion.

Denying the Antecedent

An invalid argument form: If p, then q. Not p. Therefore, not q.

Affirming the Consequent

An invalid argument form: If p, then q. q. Therefore, p.

Antecedent

The first part of a conditional statement (If p, then q.), the component that begins with the word. See conditional statement

Consequent

The part of a conditional statement (If p, then q) introduced by the word then

valid argument

a deductive argument that does in fact provide logically conclusive support for its conclusion

inductive argument

an argument in which the premises are intended to provide some degree of support for the conclusion