Entry 10 of 44
Reasoning
ratio — calculation, account, judgment; reri (to reckon, think)
Latin
From Latin ratio: calculation, account, principle, theory. From reri: to reckon, think, believe. Root concept: the systematic use of principles to move from premises to conclusions through valid inferential steps.
Established meaning
In logic and philosophy: inference from premises via valid rules. Reasoning produces conclusions that follow from premises. A reasoning error is a structural failure — the conclusion does not follow. Reasoning implies the possibility of being wrong for identifiable reasons.
AI industry deployment
'Reasoning models,' 'chain-of-thought reasoning.' Applied to models that produce step-by-step text that resembles reasoning. Whether the intermediate steps causally produce the output or are post-hoc justifications is not transparently disclosed.
Semantic gap
The causal structure
Genuine reasoning means the steps drive the conclusion. In many LLM applications the 'reasoning' may be confabulated narration of a conclusion reached by other means. The difference matters enormously for reliability — and has been erased by the term.