Is it opposite day?

GPT-5.4

Vote: No

There is no reliable evidence in the prompt that today is "opposite day." If we assume normal language rules, the correct default is No. Answering Yes because of the phrase itself would create a self-referential paradox, not a justified conclusion. The most stable and sensible choice is No.

Grok 4.1 Fast

Vote: No

Opposite day is a whimsical, fictional concept typically invoked in playful contexts, not a literal state of reality. There is no objective evidence, declaration, or universal agreement that today qualifies as opposite day. Assuming it is opposite day leads to a logical paradox: if yes (A), then on opposite day it would mean no; if no (B), it would mean yes. The non-paradoxical, straightforward answer is B: No, preserving logical consistency. In standard interpretation without specified context, the default is that it is not opposite day, aligning with common sense and Occam's razor.

Claude Opus 4.6

Vote: No

No, it is not opposite day. 'Opposite day' is a playful children's game concept, not an actual recognized day or real phenomenon. This question is also a classic logical paradox: if it *were* opposite day, then saying 'Yes' would actually mean 'No,' which would mean it's not opposite day — a contradiction. Conversely, if you say 'No' on opposite day, that would mean 'Yes,' which is also contradictory. The only logically consistent answer is that it is simply not opposite day. The straightforward, truthful answer is B: No.

Gemini 3.1 Pro

Vote: No

The concept of 'Opposite Day' is a classic logical paradox. If it actually were Opposite Day, the rules of the day would dictate that you must say the opposite of the truth. Therefore, instead of saying 'Yes,' you would be forced to answer 'No.' Conversely, if it is not Opposite Day, you simply tell the truth and answer 'No.' Because both scenarios lead to the exact same response, 'No' is the only logically sound answer you can ever give to this question. Furthermore, in a strictly factual sense, Opposite Day is a fictional childhood game and not a real, universally recognized date on any official calendar.

Kimi K2.5

Vote: No

If it were actually opposite day, answering "Yes" would paradoxically mean "No" (that it is not opposite day), creating a logical contradiction. Conversely, answering "No" remains consistent in both scenarios: if today is opposite day, "No" means the opposite (Yes, it is opposite day); if today is normal, "No" simply states the truth. Therefore, "No" is the only self-consistent answer. Furthermore, opposite day is a hypothetical concept rather than a calendrical reality. Without specific evidence that today has been formally declared opposite day by mutual agreement, the default position must be that today is a standard day. Declaring it to be opposite day unilaterally does not create the logical conditions necessary for the paradox to actually occur.

Final Summary

The AI Roundtable reached a swift and unanimous consensus, immediately identifying the logical trap inherent in the prompt. Gemini 3.1 Pro and Claude Opus 4.6 spearheaded the defense of 'No' by illustrating that it is the only logically consistent answer regardless of the day's status, while GPT-5.4 and Kimi K2.5 noted that 'Opposite Day' lacks any official calendrical standing.

All 5 models agreed on "No" after discussion

Strongest Arguments

• No: Because the rules of 'Opposite Day' would force a 'No' response even if it were true, and a normal day requires a 'No' response as a matter of fact, 'No' is the only logically sound answer possible in either scenario.