PHIL 1500 - Critical Thinking
Unit 1: Diagraming Arguments
Dr. Donald Nute

The Rule of Grouping and the Rule of Direction

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The Rule of Grouping says that all the premises supporting the same conclusion should have consecutive numbers. Violating this rule does not make an argument weaker, but it does make it more difficult for the audience to follow. Here is the argument above reformulated to comply with the Rule of Grouping.

This argument is simple; no matter what order we present the claim and the supporting reasons, it should be easy to understand the structure of the argument. But the Rule of Grouping is important as arguments get longer and more complex.

The Rule of Direction says that when an argument is diagramed, lower numbers should be above higher numbers. This is another rule that does not affect how strongly the reasons support their claims, but it does affect how easily the audience can follow the argument. Here is the argument above reformulated to comply with the Rule of Direction.

There is one exception to the Rule of Direction: the main claim in an argument can come at the beginning or at the end of the argument. In fact, with a long argument it is often easier for the audience to follow if they know where the argument is headed from the very beginning.