Example 1 - Summary

 

Here’s what we learned in this example:

 

What Arguments Are

 

§         An argument is a unit of reasoning that attempts to prove to its audience that a certain idea is true by citing other ideas as evidence.

§         The idea that the argument tries to prove true is called the “ultimate conclusion.”

All arguments have exactly one ultimate conclusion.

§         Ideas which the argument uses as evidence for the ultimate conclusion, but which the argument just assumes to be true without giving us any reason to believe them, are called “premises.”

All arguments have at least one premise, and they can have any number of them.

§          Intermediate ideas on the way from the premises to the ultimate conclusion are called “subconclusions.” An argument does give us reason to believe a subconclusion but it’s not what the argument is ultimately trying to get us to believe. Instead, the subconclusion is used as a reason to believe still another idea.

Arguments don’t need to have any subconclusions at all, although most of them do have some.

§         An inference is the connection that holds between a set of ideas, call it ‘R’ for “reason,” and another idea, call it ‘C’ for “conclusion,” when the truth of the ideas in R is supposed to establish the truth of C.

 

Identifying the Parts of the Argument

 

In order to identify the parts of an argument, do two things:

1.  Start out by asking, “What is the main idea that this argument is trying to prove?” The answer to that question is the ultimate conclusion of the argument.

2.  Then, for all other important ideas in the argument, ask “Does the argument give us reason to believe that this is true, or does the argument just take this for granted?”

If the argument does give us reason to believe an idea, it’s a subconclusion.

If the argument doesn’t give us reason to believe an idea, but instead just takes the idea for granted, it’s a premise.

 

Conclusion Indicator Expressions

 

Conclusion indicator expressions tell us that the passage is giving us reasons to believe an idea. This means that these expressions introduce conclusions (sometimes the ultimate conclusions and sometimes subconclusions).

 

There are a number of conclusion indicator expressions, including: “X. Therefore Y,” “X. Thus Y,” “X. Consequently Y,” “X. Hence Y,” “X. So Y,” “X. This goes to show that Y,” “X.  It follows that Y,” “X. As a result, Y,” “X. That’s why Y,” “X, which implies that Y,” and “X, which means that Y.” In all of these sentences, Y is a conclusion and X is the reason to believe Y. All these sentences would be diagrammed like this:

 

X

     A

           

Y

 

Diagramming Example 1

 

Our argument is diagrammed as follows:

 

1) “History is the most important subject therefore Ann should major in history.”

 

1. Ann should major in history.

2. History is the most important subject.

 

2

     A

           

1

 

Notice that

·          The conclusion indicator expression “therefore” introduces the ultimate conclusion in the passage.

·          The passage doesn’t give us any reason to believe that history is the most important subject, making that idea a premise in the argument.

·          The inference is represented as an arrow in the diagram.

·          The premise is at the top of the arrow in the diagram, with an arrow going from it but no arrow going to it.

·          The ultimate conclusion is at the bottom of the arrow in the diagram, with an arrow going to it but no arrow going from it.

 

Evaluating Example 1 – False Premises

 

When evaluating an argument, we should always ask ourselves “Do I think that this premise is true?” If we think that a premise is false then we should think that the premise is bad. 

 

In this case, the false premise makes for a bad argument because if the premise is false then the ultimate conclusion has nothing to support it.

 

1) “History is the most important subject therefore Ann should major in history.”

 

1. Ann should major in history.

2. History is the most important subject.

 

2  L

      A                 L

           

1

 

Conclusions of Bad Arguments

 

Bad arguments can have false conclusions. Bad arguments can have true conclusions. In short, deciding that an argument is bad gives us no information about the truth or falsity of the conclusion.

 

Let’s take a look at another example.