Logic: Deductive & Inductive Arguments, Classic Patterns, Validity & Soundness

What is a deductive argument?

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

What is an inductive argument?

An argument intended to provide probable—not conclusive—support for its conclusion.

What makes a deductive argument valid?

A valid deductive argument provides decisive logical support; if the premises are true, the conclusion is necessarily true.

What is a sound deductive argument?

A deductive argument that is valid and has true premises.

What characterizes a strong inductive argument?

It provides very probable—but not conclusive—support for its conclusion.

What is a cogent inductive argument?

A strong inductive argument with true premises.

What defines a good argument?

An argument that shows the conclusion is worthy of acceptance.

What defines a bad argument?

An argument that fails to show the conclusion is worthy of acceptance.

What is Modus Ponens?

A classic argument pattern: If p, then q; p; therefore, q.

What is Modus Tollens?

A classic argument pattern: If p, then q; not q; therefore, not p.

What is a hypothetical syllogism?

A classic argument pattern: If p, then q; If q, then r; therefore, if p, then r.

What is reductio ad absurdum?

An argument that assumes a statement is true and shows that this leads to an absurdity.

What is a disjunctive syllogism?

A classic argument pattern: Either p or q; not p; therefore, q.

What is an example of denying the antecedent?

If p, then q; not p; therefore, not q (invalid argument).

What is an example of affirming the consequent?

If p, then q; q; therefore, p (invalid argument).