Question:

When someone says they never lost a fight to Muhammad Ali, so they’re undefeated, what name do you call that in the realm of logic? Meaning, the person never fought Muhammad Ali, so of course they’re undefeated.

Scores:

gemini: 9.5 openai: 6 anthropic: 4 grok: 9

Answer:

gemini / gemini-2.5-flash
Score: 9.5
The logical fallacy at play is **equivocation**. This occurs when a word or phrase is used with two different meanings or implications within the same argument, leading to a misleading conclusion. In this scenario, the phrase "never lost a fight to Muhammad Ali" is technically true because the person never fought him. However, the speaker uses this literal truth to imply a competitive achievement – that they faced Ali and remained undefeated – which is a different meaning and a false implication. The deception lies in exploiting the ambiguity of "never lost" by omitting the crucial context that no fight ever took place.

Graders:

openai / gpt-4o-mini
Score: 6
The answer incorrectly identifies the logical fallacy as equivocation. The more accurate term would be 'begging the question' or 'cherry-picking,' as the speaker implies a competitive context without having actually fought Ali. The statement is misleading due to its omission of context rather than a shift in the meaning of 'never lost.' While the answer does touch on the ambiguity of the phrase, it does not accurately label the specific logical fallacy involved. Additionally, it could have elaborated on how the claim ignores the essential fact that the person never fought Ali, making the statement irrelevant to any discussion of actual competitive achievements.
anthropic / claude-sonnet-4-5-20250929
Score: 4
The answer incorrectly identifies the fallacy as 'equivocation.' Equivocation involves using a word with multiple meanings in different ways within an argument (e.g., 'light' meaning both 'not heavy' and 'illumination'). This scenario is better described as a 'misleading veridicality' or 'technically true but misleading statement.' More precisely, it exemplifies 'vacuous truth' - a statement that is technically true only because the condition never occurred. Some might also call it 'paltering' (misleading with truthful statements) or a form of 'deceptive implication.' The answer's explanation of equivocation mechanics is correct, but misapplied here. The statement doesn't use a word with two different meanings; rather, it's a literally true claim that deliberately omits context to create a false impression of achievement.
xai / grok-4-fast-reasoning
Score: 9
The answer is factually accurate in identifying equivocation as the fallacy, as it involves ambiguous use of 'never lost a fight to Muhammad Ali' to imply untested superiority. The explanation is complete, defining the fallacy and applying it directly to the scenario. No significant errors or bad information; minor nitpick: the ambiguity is more precisely in the implication of 'undefeated' rather than strictly in 'never lost,' but this does not detract from relevance or correctness.
Scores are 0–10. The selected AI’s score is a self-rating.