search

Illicit Major

(also known as: illicit process of the major term)

Description: Any form of a categorical syllogism in which the major term is distributed in the conclusion, but not in the major premise.

Logical Form:

All A are B.

No C are A.

Therefore, no C are B.

Example #1:

All hotdogs are fast food.

No hamburgers are hotdogs.

Therefore, no hamburgers are fast food.

Explanation: In our example, the major term is “fast food”, because it is the term that appears in the major premise (first premise) as the predicate and in the conclusion.  As such, in this position, it is “undistributed”.

Example #2:

All Jim Carrey movies are hilarious.

No horror movies are Jim Carrey movies.

Therefore, no horror movies are hilarious.

Explanation: In our example, the major term is “hilarious”, because it is the term that appears in the major premise (first premise) as the predicate and in the conclusion.  As such, in this position, it is “undistributed”.

Exception: None.

Tip: If you are not sure if a syllogism is fallacious or not, keep substituting the items in the syllogism for other items. If a syllogism is consistent with the form but clearly doesn’t make sense, you will know that it is fallacious.

References:

Neil, S. (1853). The Art of Reasoning: A Popular Exposition of the Principles of Logic. Walton & Maberly.

Questions about this fallacy? Ask our community!

Reason: Books I & II

This book is based on the first five years of The Dr. Bo Show, where Bo takes a critical thinking-, reason-, and science-based approach to issues that matter with the goal of educating and entertaining. Every chapter in the book explores a different aspect of reason by using a real-world issue or example.

Part one is about how science works even when the public thinks it doesn't. Part two will certainly ruffle some feathers by offering a reason- and science-based perspective on issues where political correctness has gone awry. Part three provides some data-driven advice for your health and well-being. Part four looks at human behavior and how we can better navigate our social worlds. In part five we put on our skeptical goggles and critically examine a few commonly-held beliefs. In the final section, we look at a few ways how we all can make the world a better place.

Get 20% off this book and all Bo's books*. Use the promotion code: websiteusers

* This is for the author's bookstore only. Applies to autographed hardcover, audiobook, and ebook.

Get the Book