Expanded Notes on Content Evaluation


One can have arguments that are formally impeccable and have true reasons and still be bad arguments because they are not related in the right way. For instance, consider this argument:

1. If we don't get 6 inches of rain by September, we will still be in a drought.

2. We won't get 6 inches of rain by September.

3. Either this page is here or it isnít here.

Since there is no way the conclusion of this argument can be false, there is no way that it can be false when the reasons are true; thus, this is a deductively valid argument by the standard we introduced in the preceding section. The argument is nevertheless in bad shape, due to the fact that the content of the conclusion is wholly unrelated to the content of the reasons. In a case such as this one it is easy to determine that the reasons and conclusion are not properly related, but it is not easy to make precise exactly what this involves in general. The crucial thing to determine for any argument is whether the conclusion and premises either share predicates and/or names of items, or contain predicates and/or names that stand in semantical relationships that are relevantly similar, given the nature of the argument.

For more detail on argument content, see Chapter Six of the UI Critical Thinking Handbook, and in particular, Section IV.