Proof

The last chapter described some truth functional rules of inference. The purpose of this Chapter is to show how to use such rules to construct proofs. After studying this material you should be able to:

• 1. Construct valid arguments using rules of inference.

• 2. Explain several different senses of the term ‘proof’.

• 3. Explain the difference between and tradeoffs between formal and informal proof methods.

• 4. Apply the proof methods explained here to proving the truth functional validity of argument forms and proving that statement forms are tautologies

• 5. Describe and use direct, conditional, and indirect proof strategies.

• 6. Be able to construct simple arguments using rules of inference and facts from specific subjects such as mathematics.