5 is valid because we know that both P and Q are true. That means if the conclusion is Q then it is valid because we already know it is true. For example, 1. You play the lottery (P) 2. You win the lottery (Q) Conclusion you won the lottery since we already know that is true
11 and 13 are not valid because it's either or, so when you "or" it is always inclusive. You cannot assume that one is wrong or none is right. For example, 1. You win the lottery (P) 2.You've played the lottery (Q). If you do win the lottery (2) then the conclusion is that you did not play the lottery but that is not true. You can play the lottery and not win.
5 is valid because we know that both P and Q are true. That means if the conclusion is Q then it is valid because we already know it is true. For example, 1. You play the lottery (P) 2. You win the lottery (Q) Conclusion you won the lottery since we already know that is true
ReplyDelete11 and 13 are not valid because it's either or, so when you "or" it is always inclusive. You cannot assume that one is wrong or none is right. For example, 1. You win the lottery (P) 2.You've played the lottery (Q). If you do win the lottery (2) then the conclusion is that you did not play the lottery but that is not true. You can play the lottery and not win.