In a valid categorical syllogism, what is the status of the middle term with respect to the conclusion?

• A. It must appear in the conclusion
• B. It must not appear in the conclusion
• C. It must be distributed in the conclusion
• D. It must be non-distributed in all premises

Answer: (B)

In a valid categorical syllogism, the middle term serves as the link between the two extremes (the major and minor terms) and does its work inside the premises. The conclusion, however, is about the relationship between those two extreme terms only. Because the middle term is the connector that shows how the extremes relate, it does not enter into what is asserted about the extremes in the conclusion. If the middle term appeared in the conclusion, you’d be making a claim about it itself rather than about how the major and minor terms relate, which breaks the form of a proper syllogism. Therefore, the middle term must not appear in the conclusion.