What is a "schwarzer Schimmel" (a "black white-horse"), and why is forcefully insisting people think for themselves an example of one?

A schwarzer Schimmel is a self-contradicting phrase — "Schimmel" already means a white horse, so "black white-horse" cancels itself. Decreeing "you WILL think independently" is the same kind of contradiction in action.

The German idiom schwarzer Schimmel is a built-in oxymoron: it names a thing whose two parts contradict each other, like "a square circle." It's the label for an idea that defeats itself by its own terms.

Applied to critical thinking: someone who resolutely enforces self-thinking — mandates it, drills it, grades compliance with it — is acting like a fundamentalist liberal. "Fundamentalist" (rigid, imposed-from-above) and "liberal" (open, self-determining) pull in opposite directions, so the stance contradicts itself just as "black white-horse" does. You cannot coerce someone into autonomy; the coercion negates the autonomy.

Tip: Spot the pattern wherever a method contradicts its own goal — "mandatory volunteering," "required spontaneity," "you must be free." The form is funny; the underlying lesson is serious: some ends can only be invited, never imposed.