search

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.

References: {apa}

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

{/apa}

Questions about this fallacy? Ask our community!

Eat Meat... Or Don't.

Roughly 95% of Americans don’t appear to have an ethical problem with animals being killed for food, yet all of us would have a serious problem with humans being killed for food. What does an animal lack that a human has that justifies killing the animal for food but not the human?

As you start to list properties that the animal lacks to justify eating them, you begin to realize that some humans also lack those properties, yet we don’t eat those humans. Is this logical proof that killing and eating animals for food is immoral? Don’t put away your steak knife just yet.

In Eat Meat… Or Don’t, we examine the moral arguments for and against eating meat with both philosophical and scientific rigor. This book is not about pushing some ideological agenda; it’s ultimately a book about critical thinking.

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