Critical Thinking
Section 2 - Analyzing Arguments

Argument: a set of statements of which it is claimed that one of those statements (the conclusion) is supported by the others (the premises).

To begin to analyze an argument what we need to do is identify its premises and conclusion.

Identifying the Conclusion: An argument's conclusion is what the person making the argument is ultimately trying to convince you of, i.e., the person's point. To try to identify the conclusion of an argument ask yourself 'what does the person making the argument want me to walk away thinking?' (Note if the answer is 'nothing', them you're not dealing with an argument.)

Some Conclusion Indicator Words: therefore, consequently, as a result, thus, it follows that, so
Identifying the Premises: To try to identify the premises of an argument ask yourself 'what reasons is the person giving me to accept his point?'
Some Premise Indicator Words: since, because, given that
Missing Premises and Conclusions: When trying to figure out what the premises and conclusion of an argument are, we need to ask ourselves what the person's point is. But remember that people don't always come out and say what their point is. Similarly people may not always explicitly mention all the premises they are working with. As a result, we must be prepared to identify both missing premises and missing conclusions (i.e., conclusions or premises that are not explicitly stated by the arguer, but that are implicit in what the arguer does say).
How are we supposed to tell what the arguer has in mind if he or she doesn't say it? By assuming person making the argument is rational and reasonable, e.g., that she holds the position she does because she thinks she has good reason to believe it. If an argument seems incomplete, we must ask ourselves what assumptions it is reasonable to think the person must be relying on. That is, what must this person believe in order to think she has made a coherent argument?
Consider the following argument:
I've never had any problems with the last four Fords I've owned, so my new Ford should be reliable.
Obviously that breaks up into
P1: I've never had any problems with the last four Fords I've owned
C: My new Ford should be reliable
Someone might say that the premise is irrelevant to the truth of the conclusion. If we were to respond on behalf of the person who put forward this argument what would we say? We'd say he's assuming something like the following missing premise:
MP2: If a company's products have been reliable in the past, its new products are likely to be reliable.
So, the argument is
P1: I've never had any problems with the last four Fords I've owned
MP2: If a company's products have been reliable in the past, its new products are likely to be reliable.
C: My new Ford should be reliable
With this in mind, let's look at another argument.
 
If Clinton had an affair with a 20-year-old intern, he shouldn't be President. Men who commit wicked acts do not deserve to be President.

That breaks into:

P1: Men who commit wicked acts do not deserve to be President.
C: If Clinton had an affair with a 20-year-old intern, he shouldn't be President.
Notice the argument is incomplete. Someone might say there's nothing wrong with having an affair with a 20-year-old intern. We need to fill in something like the following claim
P1: Men who commit wicked acts do not deserve to be President.
MP2: It would be wicked of Clinton to have an affair with a 20-year-old intern.
C: If Clinton had an affair with a 20-year-old intern, he shouldn't be President.
Notice that MP2 does a lot of work in the argument even though it is not clearly stated. This is often the case, hence, it's important to be sure that you have all the premises on the table when you're assessing an argument.

An Alternate Analysis: It might be suggested that the person making the above argument doesn't mean to make a merely hypothetical argument. That is, the person making the argument may be assuming that Clinton really did have an affair. That's not what the arguer literally says, but we can easily imagine a context in which this is the best interpretation of what the arguer means. If so, the argument should be analyzed as:

P1: Men who commit wicked acts do not deserve to be President.
MP2: It would be wicked of Clinton to have an affair with a 20-year-old intern.
MP3: Clinton had an affair with a 20-year-old intern
C: Clinton shouldn't be President.
Here's a trickier example. What argument, if any, is contained in the following letter to the editor (taken from The Globe and Mail, Oct. 6, 1997)?
"When France lay bleeding under the heel of Nazi Germany in 1940, the majority of Quebeckers felt that ties of blood and race were not sufficient reasons to become involved and come to the aid of France. Now the shoe is on the other foot and Quebec looks to France to provide 'friendship and solidarity' if Quebec decides to declare sovereignty.
Memories are short.
Michael Warrington, Tsawwassen, B.C."
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