What it is checking against

Two lists. The first is 163 passages we have taken the trouble to cite, each to a work and a section you can open. The second is 26 quotations that circulate under a Stoic name and belong to someone else: a screenwriter, a songwriter, Voltaire, Kant, a Victorian minister. We found most of them by auditing our own library and throwing out what did not survive.

What "not in our library" means

It means we cannot find it. It does not mean the line is fake. Our library is a few hundred passages, not the whole of ancient philosophy, and a genuine quotation can easily sit outside it.

There is also a limit worth knowing about. This tool matches wording, and translators differ. Epictetus writing that people are disturbed by their judgments rather than by events has been rendered a dozen ways in four centuries, and two of those renderings can share almost no vocabulary. A real passage in an unfamiliar translation may come back unfound.

What it does tell you is that nobody has handed you a book and a chapter. That is the thing worth noticing. A quotation that travels with a citation can be checked by anyone; one that travels with only a name has usually never been checked by anyone.

Why this matters more for Stoicism than for most

Stoic practice is built on precise distinctions, and a rewrite frequently inverts one. The best-known example is a line about everything we hear being an opinion, which is a rewrite of Meditations II.15. The original is a claim about judgment. The rewrite is a claim about the unreliability of the senses, which is not a Stoic position at all. Someone building a discipline on the second is practising something else.

The longer version of that argument, and the whole list, is on the Stoic quotes that are not Stoic. If you would rather browse passages that do check out, they are on sourced quotes.

Marcus is a daily Stoic practice for iOS, and it reads from this same checked library. No quote in the app is there unless it survived the audit.

Explore the app →