Last updated: 30 September 2026
Who we are
Mastering Epistemology (https://epis.duckdns.org/, in English and Persian) is a free, open-source guide to epistemology and critical thinking: sixteen chapters, a concept map, an audio edition, and optional study tools. It is a static website hosted on GitHub Pages. We run no server of our own, and we (the site's author) never receive your personal data. The source code is public on GitHub, so you can check everything this page says.
In short
- You can use the whole site without an account.
- There are no ads, no analytics, no tracking cookies, and no third-party trackers.
- If you sign in with Google, your study data is saved in a private app folder in your own Google Drive, which only this site can open. It is not sent to us or to anyone else.
- We do not sell, rent or share personal data, and we do not use it for advertising.
What stays in your browser
So that you can pick up where you left off, the site stores these in your browser's local storage: your reading progress, highlights and notes, your review deck, your reading and theme settings, your AI study companion settings and chats, and, if you choose to save them, chapters and audio for offline use. This data stays on your device. You can remove it at any time by clearing this site's data in your browser settings.
Google sign-in (optional)
Signing in (on My study) lets your study data follow you to other browsers and devices. Sign-in uses Google's OAuth 2.0 in your browser and asks for these permissions:
- Your name, email address and profile picture (the
openid,emailandprofilescopes), used only to show which account is signed in. They are kept in your browser. - A private app folder in your Google Drive (the
drive.appdatascope), used to create, read and update one file,epis-sync.json, that holds the study data listed above. This folder is hidden and separate from your files: the site cannot see, open or change any other file in your Drive.
Your browser talks to Google directly. The access token Google issues is short-lived, is kept in your browser, and is sent only to Google's servers. Your profile picture is loaded from Google. We never see your Google data, your token or your synced file.
The use and transfer of information received from Google APIs by this site adheres to the Google API Services User Data Policy, including the Limited Use requirements. Google user data is used only to provide the sign-in and sync features described here; it is not used for advertising, not sold, not transferred to anyone, and not read by any person.
Removing your data and access
- Sign out on the My study page: this revokes the site's access token and removes your profile and AI keys from the browser.
- Delete the synced file: in Google Drive, open Settings, then Manage apps, find this site's app, and choose “Delete hidden app data”.
- Remove the site's access to your Google account at any time at myaccount.google.com/permissions.
- Clear the data in your browser by clearing this site's data in your browser settings.
The AI study companion (optional)
The chat panel can answer questions about the page you are reading. If you add your own API key for Anthropic (Claude), OpenAI (ChatGPT), OpenRouter or another OpenAI-compatible service, your browser sends your questions, the chat so far and the text of the page you are reading directly to that provider, and that provider's privacy policy and terms apply to them. Your key is stored in your browser and, if you are signed in, in your own Drive sync file; it is sent only to the provider it belongs to.
Without a key, the panel can prepare your question for you to paste into the ChatGPT or Claude website yourself. If a free on-page assistant is offered, the service answering is named in the chat panel, and your questions and the page text are sent to it. Please do not enter sensitive personal information in the chat.
Hosting
GitHub Pages serves this site's files. Like any web host, GitHub may process technical data such as your IP address when your browser requests a page; see the GitHub General Privacy Statement. Fonts, images and audio are served from this site itself, not from other services.
Children
The site is an educational resource for a general audience and is not directed at children under 13. We do not knowingly collect personal information from children.
Changes to this policy
If this policy changes, the new version will be posted on this page with a new date. The history of every change is public in the site's source repository.
Contact
Questions about privacy, or a request about your data: please open an issue at https://github.com/Rhadadi/epis/issues.