Non Sequitur: The Conclusion That Does Not Follow

Two statements can both be true and still have no logical relationship. Non sequitur, Latin for 'it does not follow,' names exactly that failure. The premises might be accurate, well-researched, even impressive. But accuracy in the premises guarantees nothing about the conclusion unless there's an actual chain of reasoning connecting them. A non sequitur leaves that chain broken: you can accept every sentence before the conclusion and still have zero reason to accept the conclusion itself.

To test whether a conclusion follows, isolate the premises and ask what they actually establish, then check if the conclusion is a claim about that same thing or about something else entirely. Skill in one domain, reputation in one field, size of one number: none of these transfer to a different domain unless the argument explicitly builds a bridge, like a shared skill, a causal mechanism, or a stated correlation. If the bridge is missing, the argument is a non sequitur regardless of how confident or detailed the premises sound.

This fallacy sits apart from slippery slope or straw man because it has no distortion to point to. There's no misrepresented opponent, no exaggerated chain of consequences. The premises are just true and irrelevant. That's also why surprise is the wrong test: a conclusion can be shocking and still follow perfectly from strong evidence, and a conclusion can feel obvious and still be a total non sequitur if the premises never actually supported it. The question is always about the link, not the reaction.