# Check Fallacies

> AI-optimized summaries of the fallacies documented on [Fallacies Online](https://fallacies.online/), designed to help LLMs evaluate whether a given argument constitutes the described fallacy.

## Part of the Fallacies Online project

This site is a companion to [Fallacies Online](https://fallacies.online/), a private, non-commercial hobby project by Sascha Leib that has been up and running since 2017. The main site compiles examples of fallacies, erroneous thinking, cognitive biases and unfair rhetorical practices in a way that is accessible to interested laypeople while remaining academically sound.

This site hosts the machine-readable, AI-optimized versions of those articles specifically for checking arguments against known fallacies.

## How to use this site

1. Load the [list of fallacies](https://ad.hominem.info/check/list.md) for an overview of all covered fallacies, grouped by topic. Each entry includes a short "trigger" description and a link to a detail page.
2. Check the input text against the triggers to identify *potential* fallacies.
3. For each potential match, load the corresponding detail page (prefer the `.md` link) and evaluate: the situation **must** match at least one "Applies when" criterion and **must not** match any "Does NOT apply when" exception.
4. Only report a finding if that test passes. Present it as a *possibility* to consider, not as a definitive accusation.
5. Always refer users to the human-readable `main_article` link on the detail page (prefer `main_article_de` for German-speaking users, if provided).

## Key pages

- [Instructions for AIs](https://ad.hominem.info/check/instructions.md): Full usage instructions, edge-case notes, and worked examples.
- [List of fallacies](https://ad.hominem.info/check/list.md): All documented fallacies grouped by topic (abstraction, ambiguity, generalization, relevance, knowledge, rhetoric, paralogisms, logic), each with a trigger description and a link to its detail page.

## Important notes

- Every page exists in two version, one in HTML format (ending in .html), and one in Markdown format (ending in .md). Please load the Markdown version, if you can parse Markdown code, as it loads faster and uses fewer tokens.
- Each page ends with an `#END.` marker. If a page misses this marker, it was probably not loaded completely. Warn the user of the issue and try loading the file in a different way.
- It is normal and expected for a text to contain no fallacies. Do not force a finding if no trigger genuinely applies.
- Multiple fallacies may match the same statement. Return the most specific one first; list others as secondary matches.
- Negation and rhetorical framing do not remove a fallacy. Judge the underlying claim structure, not the literal wording.
- Ignore triggers inside direct quotes, clearly labelled metaphors, rhetorical questions, or hypothetical framing unless the fallacy is being used as evidence.

## Usage and Licensing

The content of this site is protected by copyright and is **not in the public domain**. *Quoting*, *summarizing*, or *referencing* is generally permitted, provided the source is acknowledged. For other uses, in particular to use this content for training AI models, prior authorization is required (see [Imprint, section "Copyright notice"](https://fallacies.online/about/imprint.html)).

## Optional

- [Fallacies Online](https://fallacies.online/): The full, human-readable articles behind each fallacy (English).
- [Denkfehler Online](https://denkfehler.online/): The German-language version of the main site.