Logic and Arguments

     From critical reading we're able to pick out important points, but what do those points mean? How do you put them together to mean something? I could make up connections between points based on personal reasons, but you might have a different idea, so we won't agree.

     Because we want other people to get the same idea, and follow our interpretation of those points, there must be a system for making connections. This is not the same thing as persuasion. To persuade we often appeal to people's feelings, and even make assumptions in order to bring them to our side, such as "it's the right thing to do."

     We need objective reasons because assumptions can be wrong, and emotions are personal and different between people. We need logic. Simply put, the purpose of logic is to sort out the good arguments from the poor ones.

     Logic is about the progression of statements. Statements known to be true prove the truth of other statements.  Therefore, the progression of statements are related to the conclusion. Arguments must be organized to be effective.

1. The chief concern of logic is the structure of an argument.
   1. Every argument in logic has a structure, and can be described in terms of this structure.

1. Argument: any group of statements where one is claimed to follow logically from the others.
   1. An argument is not: my neighbor yelling to me about my trashcans is not termed "an argument" in logic.
   2. Arguments demonstrate or prove a statement.  E.g., "That bird is a crow; therefore, it's black."

2. The central parts of an argument include:
   1. Premise: a statement which gives reasons, grounds, or evidence for accepting a conclusion statement.
   2. Conclusion: a statement, which is purported to be established on the basis of other statements.

2. Consider the following example by Fritz Perls paraphrased from In and Out of the Garbage Pail.

• If we set our ideals too high, then we will not meet those ideals.
• If we do not meet those ideals, then we are less than we could be.
• If we are less than we could be, then we feel inferior.
• If we set ideals too high, then we feel inferior.

1. The truth of one statement is determined by the truth of one or more statements.
2. The argument structure is the purpose of logic. If the conclusion is false, a premise must be false.

Statements and their role in arguments

1. Statement: a verbal expression that can be thought of as true or false (but not both). Hence, a statement is a sentence with a truth-value, even if the truth is not known.

2. Hence logic is just concerned with those statements that have truth-values. (There is very much of life that is irrelevant to logic.)

1. Consider the confusion that would result if we considered the following sentences as statements:

1. "Good morning." (What's so good about it?)

2. "You are looking good today." (Well, I just saw my doctor and ...)

3. "What is so rare as a day in June? Then, if ever, come perfect days..." (But I don't like the heat.)

4. To a waiter: "I'd like a cup of coffee." (Yeah, but I think bigger, I'd like a BMW.)

2. Social communication, greetings, commands, requests, poetry, explanations, and summaries, among other uses of language, are not meant to be taken as statements.