Apodictic

Absolutely certain, having been shown

In case it’s not obvious, we like to use real quotes that have working examples, but don’t necessarily endorse their contents…

Examples:

We know this apodictic rock beneath our feet. That dogmatic sun above our heads. The world of dreams, the agony of love and the foresight of death. That is all we know. And all we need to know? Challenge that statement.
— Edward Abbey, The Monkey Wrench Gang

But all these ideas, regardless of how convincing they may be for the individual, are submitted to the critical examination of this individual and hence to a fluctuating affirmation or negation until emotional divination or knowledge assumes the binding force of apodictic faith.
— Adolph Hitler, Mein Kampf

Etymology:

Greek, apo = “away”, dieknynai = “to show”