5.2 Logical Statements

By the end of this section, you will be able to:

• Identify the necessary and sufficient conditions in conditionals and universal affirmative statements.
• Describe counterexamples for statements.
• Assess the truth of conditionals and universal statements using counterexamples.

Specific types of statements have a particular meaning in logic, and such statements are frequently used by philosophers in their arguments. Of particular importance is the conditional, which expresses the logical relations between two propositions. Conditional statements are used to accurately describe the world or construct a theory. Counterexamples are statements used to disprove a conditional. Universal statements are statements that assert something about every member of a set of things and are an alternative way to describe a conditional.