2.11: Detecting Obscure Argumentation

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Page ID: 36042

Bradley H. Dowden
California State University Sacramento

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It takes detective skills to detect the essence of an argument among all the irrelevant remarks that people make while they argue. Speaking of detective skills, I was 14 years old when my mother, a second-string member of the Folies Bergère dance group in Paris, was dancing for the troops of the French Foreign Legion in Morocco. She had left me back in Paris with Mathilde, an indifferent governess and a veteran of the French Resistance. One dark and stormy night, Mathilde came up behind me, reached into my.... But I've gotten off the subject, haven't I?

Exercise \(\PageIndex{1}\)

Photo by Fernando de Sousa, Melbourne, Australia

Two people are sitting in a dark movie theater a row behind you, and you hear this conversation.

Man: Do you have the two snakes we brought in with us?
Woman: No, I thought you had them.
Man: Oh!

You should draw a conclusion from this conversation, even if no speaker is asking you to draw a conclusion. What conclusion?

Answer: Snakes have gotten loose near you in the theater

Another difficulty in spotting arguments is that they can differ greatly in their structure. Instead of backing up a conclusion by only one package of reasons, an arguer might give a variety of lines of argument for the conclusion. That is, the arguer could produce two or more sets of reasons in support of the conclusion, and might even add why the opposition's argument contains errors. Jones did this in our earlier courtroom story. He gave a set of reasons for acquittal by arguing that there is an alternative explanation of all the facts about the robbery. In addition, he argued that the prosecution's strong reliance on the clerk's testimony is no good because the clerk stole from her sorority.

Arguments can have other complexities, too. Often arguers defend one or more of their reasons with reasons for those reasons, and even reasons for those reasons, and so forth. An arguer may simultaneously argue for several conclusions, or draw a second conclusion from a first conclusion. So, the structure of an argument can become quite complex. However, just as molecules are composed of atoms, so complex arguments are composed of "atomic" arguments, each with its own single conclusion and basic reasons to back it up. Breaking down complex arguments into their simpler elements in this way can make the complex arguments more understandable.

Mathematics professors who create a proof rarely state every step in their proof. However, if the argument is correct, that is, sound, then the reasoning from any one step to another can be reconstructed as a deductively valid argument. For math experts, the reconstruction process is easier than for the rest of us.

Here is an interesting dialogue that contains an obscure argument. Evidently this dialogue occurred several centuries ago.

King: I told you to bring me a head of a witch, and you’ve given me the head of a necromancer.
Executioner: The Inquisition has declared that all necromancers are witches.
King: Oh, all right then.

By saying, "Oh, all right then," the king infers that he has in fact been given the head of a witch. In his reasoning, he uses the following deductively valid, but implicit, sub-argument:

All necromancers are witches.
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All heads of necromancers are heads of witches.

Let’s do more exploration of how arguments have sub-arguments. If you were asked whether the statement, "She probably won't be here to chair the meeting," is a premise or a conclusion in the following argument, the right response would be to say "Both" because it is a basic premise, but it is also argued for.

She's got the flu again, so she probably won't be here to chair the meeting. Therefore, I'll have to do it. Damn!

The word so is a conclusion indicator of the sub-conclusion, and the word therefore is a conclusion indicator of the final conclusion, or last conclusion. Here are the two arguments:

She's got the flu again.
So, she probably won't be here to chair the meeting.

She probably won't be here to chair the meeting.
So, I'll have to chair the meeting.

Now it is clearer how the same sentence is both a premise and a conclusion.

Exercise \(\PageIndex{1}\)

The word so is a conclusion indicator in the following passage. Is it an indicator of the final conclusion or only of a sub-conclusion on the way to the final conclusion?

It's safe to conclude that all the patients given the AIDS antidote now have red hair. Remember, Janelle had red hair before the experiment, and there has been no change in her hair color; Rudy has fairly red hair; and Sam's hair has now changed to red, hasn't it? So, all three have red hair. But these three are the only patients that were given the AIDS antidote.

Answer: Sub-conclusion. This sub-conclusion is a basic premise for the final conclusion that all the patients given the AIDS antidote now have red hair.