(also known as: kettle logic [form of], internal contradiction [form of], logical inconsistency [form of])
Description: In terms of a fallacious argument, one or more propositions are asserted that cannot both possibly be true. In a more general sense, holding one or more views/beliefs that cannot be all be true together. Quotes from Yogi Berra (even if apocryphal) are great examples of fallacies, especially inconsistencies.
"I never said most of the things I said." - Yogi Berra
Explanation: I know this requires no explanation, and I don't mean to insult your intelligence, but for consistency sake, I will explain. If he had said those things, then he said them, which is a contradiction to his claim that he never said them.
"Nobody goes there anymore. It's too crowded." - Yogi Berra
Explanation: Again, I apologize, but here it goes... If "nobody" went there, then it could not possibly be crowded, since "crowded" implies too many people are there.
Exception: One needs to be able to explain how the beliefs are not inconsistent.
Tip: Think about your beliefs. Are there any inconsistent with each other? With how you act and what you do?
Variation: The internal contradiction is a blatant contradiction in the same argument (thus “internal”).
I never had sexual relations with that woman -- but it sure was nice!
Kettle logic is usually multiple, contradicting arguments, supporting a single point. In an example used by Sigmund Freud in The Interpretation of Dreams, a man accused by his neighbor of having returned a kettle in a damaged condition offered three arguments:
That he had returned the kettle undamaged;
That it was already damaged when he borrowed it;
That he had never borrowed it in the first place.
A logical inconsistency usually refers specifically to inconsistencies in formal, or deductive, logic.
Ted is older than Sam. Bill is older than Ted. Sam is older than Bill.