---
title: "What is Witnessability? | Evidence and Claims"
description: "Understand witnessability: how evidence and explicit reasoning make a specific claim assessable, challengeable and bounded by what can be established."
canonical: "https://witnessability.io/what-is-witnessability/"
representation: "Website reading format; consult linked publications for their exact status and terms."
---

[Witnessability](https://witnessability.io/) / Start here

# What is Witnessability?

Witnessability concerns our ability to produce, preserve and make available the evidence and reasoning needed to assess a specific claim. It starts with a question: what can someone establish about something they did not observe themselves?

Witnessability editorial explanation · 30 October 2026\
Prepared with AI assistance. [Authorship and responsibility](https://witnessability.io/about/#authorship).\
Read the linked publications for their exact definitions and status.

## Start with the claim

A record is useful in relation to a question. A signed document, a laboratory measurement and a software log may each provide evidence, but they do not answer every question about the activity behind them. Witnessability asks how a claim connects to the conditions under which that evidence was produced and to the reasoning offered in support of it.

The Conceptual Core describes this as a claim-relative capability of a socio-technical arrangement. In plain language, people, instruments, procedures and systems must make the relevant grounds available for evaluation and challenge. The object of inquiry may be a research result, an organizational decision or an automated action. AI and software execution are important applications within that wider subject.

## A payment record is a starting point

Suppose a service produces a signed record saying that an invoice was paid. A successful signature check establishes a property of the signed bytes under the specified key and verification assumptions. Whether that key belongs to the expected source is another question. Neither conclusion alone establishes that funds moved.

A record from the payment network may support a different claim about a transfer observed there. To use it for this invoice, the relationship between the exact action, invoice and network record must also be established. A final or durable outcome requires the applicable settlement and finality conditions. Even then, the evidence does not automatically establish that every business obligation was satisfied.

## Make the reasoning inspectable

A useful explanation identifies the evidence, the conditions of its production, the assumptions used and the conclusion they support. It also identifies what a reviewer would need to challenge. More records can improve the available basis, but quantity alone does not establish independence or completeness.

- Name the exact claim, including its subject, scope and time.
- Identify what the available evidence observed, constitutes or proves.
- Explain how that evidence is connected to the claim.
- State which assumptions were checked and which remain relied upon.
- Report the supported conclusion and the questions that remain open.

## Move from explanation to source

The Conceptual Core provides the broader conceptual foundation. The Witnessability Model examines AI and software execution evidence. Claim Boundaries for Execution Evidence, or CBEE, develops a protocol-neutral appraisal discipline for execution-related claims. These works have distinct scopes and publication statuses; an explanation on this website does not revise their versioned text.

For a practical next step, read the guide to verification, appraisal and reliance, then apply its questions to one record you already use. Begin with the conclusion you need, rather than assuming that a familiar artifact is sufficient.

## Sources and next steps

- [Witnessability Conceptual Core 1.0](https://witnessability.io/core/1.0/)
- [Conceptual Core repository and release records](https://github.com/Witnessability/witnessability-core)
- [Claim Boundaries for Execution Evidence, revision 02](https://datatracker.ietf.org/doc/draft-sergeev-claim-boundaries/02/)

## What this does not claim

This is a plain-language introduction, not a replacement for the versioned Conceptual Core. Witnessability does not guarantee that sources are honest, that every fact is knowable or that a decision based on evidence is wise, safe or lawful.