search

Become an active member of our fallacy-discussing community (or just become a lurker!)

Definist Fallacy

(also known as: persuasive definition fallacy, redefinition)

Description: Defining a term in such a way that makes one’s position much easier to defend.

Logical Form:

A has definition X.

X is harmful to my argument.

Therefore, A has definition Y.

Example #1:

Before we argue about the truth of creationism, let’s define creationism as, “The acceptance of a set of beliefs even more ridiculous than those of flat-earthers.”

Example #2:

Before we argue about the truth of creationism, let’s define evolution as, “Faith in a crackpot theory that is impossible to prove with certainty.”

Explanation: It should be clear by the two examples who is defending what position.  Both arguers are taking the opportunity to define a term as a way to take a cheap shot at the opponent.  In some cases, they might actually hope their definition is accepted, which would make it very easy to defend, compared to the actual definition.

Exception: When a definition used is really an accurate definition from credible sources, regardless of the damage it might do to a position.

Tip: Do not accept definitions put forth by the opponent unless you researched your definition on your own, and agree.

References:

Bunnin, N., & Yu, J. (2008). The Blackwell Dictionary of Western Philosophy. John Wiley & Sons.

Questions about this fallacy? Ask our community!

Grow Intellectually by Taking Dr. Bo's Online Courses

Dr. Bo is creating online courses in the area of critical thinking, reason, science, psychology, philosophy, and well-being. These courses are self-paced and presented in small, easy-to-digest nuggets of information. Use the code FALLACYFRIENDS to get 25% off any or all of Dr. Bo's courses.

View All Dr. Bo's Courses