Berk Bayri

A convincing explanation shows how the AI reached the answer

A common misconception about AI models and evaluation, tested against the evidence.

The myth
If an AI gives a coherent step-by-step explanation after an answer, that explanation reveals the process that actually produced the answer.
The reality
An AI-generated explanation can be useful without being a faithful trace. Models can produce plausible reasoning that does not match the mechanism that drove the answer.

Explanation and evidence

The argument

When an AI gives the right answer and then explains it beautifully, the explanation feels like a window into the process.

Sometimes it is. Sometimes it is a reconstruction.

Anthropic's mechanistic interpretability work provides unusually direct examples. In one simple arithmetic case, the model gave the right answer, then described a familiar carry-the-one procedure. Internal attribution analysis suggested that was not the mechanism it had used. The same research identifies cases where a model works backward from a human-provided target and produces a plausible chain of reasoning that arrives there.

That does not make explanations useless. It changes what they are evidence of.

A good explanation can show that an answer is understandable without proving that the model actually arrived there that way.

Why people believe it

For humans, "show your work" is a useful accountability technique. A written derivation can expose a mistake and often corresponds to the reasoning the person performed.

Language models are trained to generate convincing explanations too. The ability to narrate a method and the mechanism that produced an output are not guaranteed to be identical.

What the evidence says

Research on chain-of-thought faithfulness is nuanced. Some reasoning traces can be highly informative, particularly when a task genuinely requires sequential reasoning. Other experiments show omissions, rationalizations and sensitivity to hidden hints.

So the mistake is not reading explanations. It is treating the explanation as a forensic log.

The better question

Use the explanation to generate checkable intermediate claims.

Then verify those claims with calculation, code, sources or external evidence.

If you need an audit trail, prefer actual , retrieved documents, timestamps and recorded actions over a narrative that merely sounds like one.

Sources

On the Biology of a Large Language Model

Anthropic · 2025-03-27

CoT May Be Highly Informative Despite ‘Unfaithfulness’

METR · 2025-08-08

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