Critical thinking - making sure we have good reasons for our beliefs.

“Monty won’t be at the party.” - Points: 1. I can’t stand him and I want to have a good time Bad reason 2. He’s really shy and rarely goes to parties Ampliative argument 3. He’s in China Deductive argument

A reason is good, when it makes a belief highly probably to be true. Rational people want to have good beliefs. Form beliefs only when you find good reasons for them.

Argument, a set of statements that together comprise a reason for a further statement. Reasons, are premises. Conclusion.

Good arguments support their conclusions. Evaluate arguments to determine whether or not they’re good or bad.

Argument 1 (bad argument) Premise 1: I can’t stand Monty Premise 2: I want to have a good time Conclusion: Monty won’t be at the party (extra hidden premise could stop Monty going, e.g. person making the argument decides who goes to the party)

Argument 2 (deductive argument) Premise 1: Monty is in Beijing Premise 2: It is impossible to get here from Beijing in time Conclusion: Monty won’t be at the party The truth of the premises guarantee the truth of the conclusion.

Argument 3 (ampliative argument) Premise 1: Monty is shy Premise 2: Monty rarely goes to parties Conclusion: Monty won’t be at the party He could still go to the party, but it does make it more likely he won’t. The conclusion is made probable.