PXL_20231028_053959939

N Chapter 1: Argument Structure 1.1 What Is an Argument? -An M is a sequence of statements one of which is intended as the conclusion and the others, fiemb&s are intended to support the conclusion. (There are bad arguments as well as good ones; a bad argument is still an argument.) The premises and conclusion of an argument are always m (or propositions or declarative sentences), as opposed to questions, commands, or exclamations. -A Y is an assertion that is either true or false. Notes: e A conditional (if-then) statement itself is not an argument. Compare: o If today is Monday, there is a Monday Night Football. o Because today is Monday, there is a Monday Night Football. Today is Monday, so there is a Monday Night Football. (0] ) argument is an argument whose conclusion follows necessarily from its premises. m:m (deductive, or valid, : An argument is deductively valid iff (= if and only if) the following is impossible: all its premises are true and yet the conclusion is false. An argument that is not valid is invalid. Deduction <=> Induction, abduction e Deduction. The sun arises from the east every day. So, tomorrow, the sun will arise from the-east. Induction. The sun has always arisen from the easy in the past. So, tomorrow, the sun will arise from the L om the east and sets to the west. east. Abduction (or inference to the best explanation). The sun always arises fr Why? Perhaps the earth rotates eastwards. A m argument is (1) a valid argument in which (2) all its premises are in fact true. An argument that is not sound is unsound. luestion: Which of the following is valid, which is invalid? Which is sound, which is unsound. If we have a logic class today, | will have a good time s We have a logic class today. Therefore, | will have a good time. 2. |If today is Friday, we will have a logic class today Today is Friday. Therefore, we will have a logic class today 3. Earth is round. Ravens are black. Therefore, the sky is blue.