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LLMs Will Always Hallucinate, and We Need to Live With This
arxiv.orgAs Large Language Models become more ubiquitous across domains, it becomes important to examine their inherent limitations critically. This work argues that hallucinations in language models are not just occasional errors but an inevitable feature of these systems. We demonstrate that hallucinations stem from the fundamental mathematical and logical structure of LLMs. It is, therefore, impossible to eliminate them through architectural improvements, dataset enhancements, or fact-checking mechanisms. Our analysis draws on computational theory and Godel's First Incompleteness Theorem, which references the undecidability of problems like the Halting, Emptiness, and Acceptance Problems. We demonstrate that every stage of the LLM process-from training data compilation to fact retrieval, intent classification, and text generation-will have a non-zero probability of producing hallucinations. This work introduces the concept of Structural Hallucination as an intrinsic nature of these systems. By establishing the mathematical certainty of hallucinations, we challenge the prevailing notion that they can be fully mitigated.



It’s worth noting that humans aren’t immune to the problem either. The real solution will be to have a system that can do reasoning and have a heuristic for figuring out what’s likely a hallucination or not. The reason we’re able to do that is because we interact with the outside world, and we get feedback when our internal model diverges from it that allows us to bring it in sync.