Large language models hallucinate because they are trained to predict plausible next words rather than to verify truth.

Is it true that large language models hallucinate because they are trained to predict plausible next words rather than to verify truth?

Partly. One reference confirms LLMs are pretrained to predict the next word, but does not establish that this is why they hallucinate. Two items from the same paper argue hallucination instead stems from training and evaluation procedures rewarding guessing over acknowledging uncertainty, and another attributes it partly to supervised fine-tuning rewarding always responding.

Verdict: CONTESTED PARTIAL · 1 source for, 3 against · Last checked 3 Oct 2026

The private library was unavailable for some searches in this check. Missing library results are not evidence against the claim.

Large language model. (n.d.). en.wikipedia.org. https://en.wikipedia.org/wiki/Large_language_model

Why Language Models Hallucinate. (2025). doi.org. https://doi.org/10.48550/arxiv.2509.04664

Why Language Models Hallucinate. (n.d.). arxiv.org. https://arxiv.org/html/2509.04664v1

HypoTermInstruct: Instructing Large Language Models not to Hallucinate. (n.d.). openreview.net. https://openreview.net/forum?id=pfmacmILs2