6B Mood and Figure
- Mood and figure give you two important pieces of information about a categorical syllogism. Mood tells you the quantity and quality of the major premise, the minor premise, and the conclusion of a categorical syllogism; for example, EIO means that the major premise is an E-proposition, the minor premise is an I- proposition, and the conclusion is an O-proposition. Figure tells you the placement of the middle term in the premises:
Thus, EIO-4 represents the following categorical syllogism, in which the middle term is in Figure 4:
- No P are M.
- Some M are S.
- Some S are not P.
6C Diagramming in the Modern Interpretation
- Categorical syllogism:
- All S. are M.
- No P are M.
- No S are P.
Conclusion “No S are P” is represented in diagram. Argument is VALID.
- Both Chapter 1 and section H of this chapter cover incomplete arguments. If you understand how to identify what’s missing in an argument, you can successfully tackle the special type of enthymeme called a sorites.
Unlike a categorical syllogism with only two premises and a conclusion, a sorites has more than two premises and a conclusion. Your job is to organize the argument so that you can create a series of categorical syllogisms out of a sorites.
Follow these steps:
- Be sure the argument is translated into standard-form categorical propositions, paraphrasing as appropriate.
- Reveal the form of the argument by replacing terms with letters.
- Put the argument elements in order by identifying the conclusion’s predicate. Then locate that same term in one of the premises. This becomes the first premise. Repeat until you’ve accounted for all of the premises. The subject term of the conclusion will be found in the last premise of the sorites.
- The first two premises should yield a conclusion that is presently missing. Assert that conclusion.
- You are now ready to diagram the first two premises. If the argument is valid, you can use the conclusion as the first premise in the next leg of the argument.