Merriam-Webster Logo
SINCE 1828
Menu
dictionary thesaurus

law of contradiction

Definition of law of contradiction

: a principle in logic: a thing cannot at the same time both be and not be of a specified kind (as a table and not a table) or in a specified manner (as red or not red)

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Learn More about law of contradiction

Share law of contradiction

Statistics for law of contradiction

Look-up Popularity

Comments on law of contradiction

What made you want to look up law of contradiction? Please tell us where you read or heard it (including the quote, if possible).

Show Comments  Hide Comments 

WORD OF THE DAY

substantive

important, real, or meaningful

Get Word of the Day daily email!

Test Your Vocabulary

Homophone Quiz

  • three-bears-two-of-them-look-like-theyre-whispering-to-a-third-bear-who-looks-chuffed-to-be-the-center-of-attention
  • In order to judge how people felt, the senator's office hired a firm to take a ______.
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
Word Winder's CrossWinder

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Words at Play

Ask the Editors

Word Games