Evaluating the Logic of an Argument

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For more on argument, see Chapter 19.

An argument includes a thesis backed by reasons and support. The thesis asserts a position on a controversial issue or a solution to a problem that the writer wants readers to accept. The reasons tell readers why they should accept the thesis, and the support (such as examples, statistics, authorities, and textual evidence) gives readers grounds for accepting it. For an argument to be considered logically acceptable, it must meet the three conditions of what we call the ABC test:

The ABC Test

  1. The reasons and support must be appropriate to the thesis.
  2. The reasons and support must be believable.
  3. The reasons and support must be consistent with one another as well as complete.