Accused of a fallacy? Suspect a fallacy? Ask Dr. Bo and the community!

Quickly register to comment, ask and respond to questions, and get FREE access to our passive online course on cognitive biases!

one moment please...

Quantifier-Shift Fallacy

(also known as: illicit quantifier shift)

Description: A fallacy of reversing the order of two quantifiers.

Logical Form:

Every X has a related Y.

Therefore, there is some Y related to every X.

Example #1:

Everybody has a mother.

Therefore, there is some woman out there who is the mother of us all.

Explanation: While it is true that everyone has (or had) a mother, the term “mother” is not a singular term that is shared -- it is implied that it is a category in which many mothers reside.  The conclusion is asserting the opposite of the meaning -- that there is actually just one mother shared by everyone.  This form of reasoning is invalid; therefore, fallacious.

Example #2:

Everybody has a brain.

Therefore, there is a single brain we all share.

Explanation: Everybody has his or her own brain, not one we all share.  Although I have met many people who seem not to have their own brain.  This form of reasoning is invalid; therefore, fallacious.

Exception: None.


Cook, R. T. (2009). A Dictionary of Philosophical Logic. Edinburgh University Press.

Registered User Comments

Become a Logical Fallacy Master. Choose Your Poison.

Logically Fallacious is one of the most comprehensive collections of logical fallacies with all original examples and easy to understand descriptions; perfect for educators, debaters, or anyone who wants to improve his or her reasoning skills.

Get the book, Logically Fallacious by Bo Bennett, PhD by selecting one of the following options:

Not Much of a Reader? No Problem!

Enroll in the Mastering Logical Fallacies Online Course. Over 10 hours of video and interactive learning. Go beyond the book!

Enroll in the Fallacy-A-Day Passive Course. Sit back and learn fallacies the easy way—in just a few minutes per day, via e-mail delivery.

Have a podcast or know someone who does? Putting on a conference? Dr. Bennett is available for interviews and public speaking events. Contact him directly here.

About Archieboy Holdings, LLC. Privacy Policy Other Books Written by Bo
 Website Design and Software Copyright 2018, Archieboy Holdings, LLC.