Theodore Gracyk
Philosophy 110: Practical Reasoning


Sample Portfolio Page: Modus Ponens

This page has all four elements of a correct page:

  1. At the top, it labels the category of argument. 
  2. It documents the source. (Provide the same sort of documentation that would be used for a citation in a college research paper.)
  3. It identifies the issue in the form of a question. 
  4. It evaluates its soundness. (For the fallacies, we skip the standard form reconstruction but explain how the fallacy occurs in the example.) It explicitly states whether the argument is sound or unsound.

          

 

Modus Ponens

 

If it's got to be clean, it's got to be Tide.

 

Source:  Good Housekeeping, March 1993, p. 18   

Issue: Should I buy Tide?

1. If my clothes have got to be clean, then I should buy Tide.

2. My clothes have got to be clean.                                 

I should buy Tide

Evaluation: The argument is valid because we can repair it as a modus ponens argument.

However, the first premise is not true. There are other products that will get my clothes just as clean. I can use one of them instead.

Because of the false premise, this argument is unsound.

 

 

 

 

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    Last updated July 27, 2004